Sunday, May 13, 2018

Happy Mother's Day

Happy Mother's Day to all! Here is some mother-child artwork in honor of this day. Hope you had a wonderful day with your families.

Artist: Mary Cassat
May you treasure your time with your children. Be with them as much as you can.

Artist: Diego Rivera
Embrace the now, for all too soon, your children will be all grown up. It will go by in a heartbeat, I promise you.

Artist: David Foggie
Your parenting season feels long at times when you are in the middle of it, but when you near the end of it, it feels like it was the most brief moment in time. Be sure you take time to enjoy it as you go.

Artist: Albert Anker
Live into each moment, as deeply as you can. You will never get it back.

Haitian birth, artist unknown
Deepest gratitude to those who attend women in their pregnancies and births, and who help them through it with respect and care.

Photo from Amnesty International
You make such a difference to so many, in ways you may not realize for a long time.


Extra hugs to those whose own mothers are no longer living or in their lives. Special loving to those whose have lost children through adoption, miscarriage, stillbirth, or death at any age. We honor your pain. You and your experiences matter too. You are loved.

Monday, April 30, 2018

VBAC after VBAC: Decreased Risk


A large new study on VBAC after prior VBAC has just come out, and it affirms what we've seen before, that risk for subsequent labors goes down and success rates go up after a previous VBAC.

Krispin 2018 Study

This is a large retrospective cohort study from Israel. It looked back at all women who attempted a VBAC at a major hospital over a period of 7 years (2007-2014).

The study group (n=1,211) contained the women with at least one prior VBAC. The control group (n=2,045) was comprised of women pursuing their first VBAC.

As we've seen before, a prior VBAC increases the chances of another VBAC. So it was in this study, too. Those with a prior VBAC had a 96% subsequent VBAC rate. (I think that's the highest VBAC rate of any study I've ever seen!)

However, even the women pursuing their first VBAC had a high rate, nearly 85%. This suggests that the Israelis are doing something right when it comes to attending VBACs, because their VBAC rates are much better than those of many U.S. hospitals.

Induction of labor was associated with reduced VBAC rates, cutting the VBAC odds by half, but induction rates were fairly low compared to some practices. This allowed the success rate to stay high overall.

The study confirmed that a prior VBAC greatly lessens the risk for uterine rupture (UR). The uterine rupture rate in those with a prior VBAC was 0.7%, whereas it was 1.6% in the women with their first Trial of Labor (TOL).

The take-home from this study is that when other variables were controlled for, having a prior VBAC cut the odds for uterine rupture in half in subsequent labors. 

Even so, both groups of UR numbers seem a little high, probably because the hospital used prostaglandins (PGE2) to induce their VBACs. Prostaglandins (and especially prostaglandins plus pitocin) have been shown to increase the risk for uterine rupture. Unfortunately, the study did not share the rupture rate in the induced groups vs. the rupture rate in the spontaneous labor groups. That would have been illuminating.

It's also important to point out that the risk for rupture wasn't zero. Even after a VBAC, uterine rupture is still a potential risk and has been known to occur. Neither is prior VBAC a guarantee of subsequent VBAC outcomes; there's always a chance of another cesarean because unpredictable things happen in labor.

But it's good to confirm again that the risk for uterine rupture is substantially lower once you've had a VBAC, and that your chances of having another VBAC are very good indeed.

Other VBAC after VBAC Studies

This is not the first study on successive multiple VBACs. Prior research also shows improved outcomes with previous VBAC. For example, Shimonivitz (2000) found the risk for uterine rupture "decreased dramatically" once a woman has had a VBAC.

Some women have reported being told that risk for uterine rupture goes back up again after a certain number of VBACs and that therefore only a few VBACs can be allowed before a woman is required to have repeat cesareans again. This claim is not based in research at all and flies in the face of common sense.

The most definitive study on this claim is Mercer (2008), who studied multiple successive VBACs in 19 hospitals in the MFMU network. They found that UR rates dropped after the first VBAC and remained low thereafter:
Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter.
The other consideration is that if a woman is not "allowed" to VBAC, she ends up with multiple repeat cesareans, which carry significant risks of complications such as placenta previa, placenta accreta, bladder and bowel injuries, hemorrhage, and hysterectomy (Silver 2006). The risk is dose-dependent, meaning that the risk increases with every successive cesarean a woman has. If a woman is planning a large family, the evidence clearly shows that repeated VBACs are far safer than repeated cesareans.

As Mercer et al. conclude:
Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy. There is no reason to place a limit on the number of VBACs a woman can have.
Summary

Once you've had a VBAC, you have an even better chance than before at another VBAC. It's not a guarantee, of course, but most studies show the VBAC after VBAC rate to be above 90%.

The uterine rupture rate after prior VBAC seems to fall between 0.4% and 0.7%. However, it will vary depending on how much induction is used, what induction methods are used, how aggressive providers are with augmentation, and any other other risk factors present. Whatever the exact number is, studies show that the uterine rupture rate decreases strongly after a prior VBAC but there should always be an awareness of the possibility.

The bottom line is that the risk for poor outcomes goes down with successive VBACs, while the risk for poor outcomes goes up with multiple repeat cesareans. In most cases, VBAC after VBAC offers far more advantages and should not be restricted. 


References

J Matern Fetal Neonatal Med. 2018 Apr;31(8):1066-1072. doi: 10.1080/14767058.2017.1306513. Epub 2017 Mar 27. Association between prior vaginal birth after cesarean and subsequent labor outcome. Krispin E, Hiersch L, Wilk Goldsher Y, Wiznitzer A, Yogev Y, Ashwal E. PMID: 28285573
OBJECTIVE: To estimate the effect of prior successful vaginal birth after cesarean (VBAC) on the rate of uterine rupture and delivery outcome in women undergoing labor after cesarean. METHODS: A retrospective cohort study of all women attempting labor after cesarean delivery in a university-affiliated tertiary-hospital (2007-2014) was conducted. Study group included women attempting vaginal delivery with a history of cesarean delivery and at least one prior VBAC. Control group included women attempting first vaginal delivery following cesarean delivery. Primary outcome was defined as the rate of uterine rupture. Secondary outcomes were delivery and maternal outcomes. RESULTS: Of 62,463 deliveries during the study period, 3256 met inclusion criteria. One thousand two hundred and eleven women had VBAC prior to the index labor and 2045 underwent their first labor after cesarean. Women in the study group had a significantly lower rate of uterine rupture 9 (0.7%) in respect to control 33 (1.6%), p = .036, and had a higher rate of successful vaginal birth (96 vs. 84.9%, p < .001). In multivariate analysis, previous VBAC was associated with decreased risk of uterine rupture (OR = 0.46, 95% CI 0.21-0.97, p = .04). CONCLUSIONS: In women attempting labor after cesarean, prior VBAC appears to be associated with lower rate of uterine rupture and higher rate of successful vaginal birth.
Similar Studies on VBAC After VBAC

Mercer BM, Gilbert S, Landon MB. et al. Labor Outcomes With Increasing Number of Prior Vaginal Births After Cesarean Delivery. Obstet Gynecol. 2008 Feb;111(2):285-291. PMID: 18238964 You can read the entire study here.
OBJECTIVE: To estimate the success rates and risks of an attempted vaginal birth after cesarean delivery (VBAC) according to the number of prior successful VBACs. METHODS: From a prospective multicenter registry collected at 19 clinical centers from 1999 to 2002, we selected women with one or more prior low transverse cesarean deliveries who attempted a VBAC in the current pregnancy. Outcomes were compared according to the number of prior VBAC attempts subsequent to the last cesarean delivery. RESULTS: Among 13,532 women meeting eligibility criteria, VBAC success increased with increasing number of prior VBACs: 63.3%, 87.6%, 90.9%, 90.6%, and 91.6% for those with 0, 1, 2, 3, and 4 or more prior VBACs, respectively (P<.001). The rate of uterine rupture decreased after the first successful VBAC and did not increase thereafter: 0.87%, 0.45%, 0.38%, 0.54%, 0.52% (P=.03). The risk of uterine dehiscence and other peripartum complications also declined statistically after the first successful VBAC. No increase in neonatal morbidities was seen with increasing VBAC number thereafter. CONCLUSION: Women with prior successful VBAC attempts are at low risk for maternal and neonatal complications during subsequent VBAC attempts. An increasing number of prior VBACs is associated with a greater probability of VBAC success, as well as a lower risk of uterine rupture and perinatal complications in the current pregnancy.
Isr Med Assoc J 2000 Jul;2(7):526-8. Successful first vaginal birth after cesarean section: a predictor of reduced risk for uterine rupture in subsequent deliveries. Shimonovitz S, Botosneano A, Hochner-Celnikier D. PMID: 10979328
...Although a vaginal birth after a cesarean is considered safe in modern obstetrics, it is not known whether repeated VBACs increase the risk of rupture, or whether the first VBAC proves the strength and durability of the scar, predicting further successful and less risky vaginal deliveries. OBJECTIVES: To evaluate the effect of repeated vaginal deliveries on the risk of uterine rupture in women who have previously delivered by cesarean section. METHODS: In this retrospective study, 26 VBAC deliveries complicated by uterine rupture were matched for age, parity, and gravidity with 66 controls who achieved VBAC without rupture... We found that the risk of rupture decreases dramatically in subsequent VBACs. Of the 40 cases of uterine rupture recorded during the 18 year study period, 26 occurred during VBAC deliveries. Of these, 21 were complicated first VBACs. We also found that the use of prostaglandin-estradiol, instrumental deliveries, and oxytocin had been used significantly more often during deliveries complicated with rupture than in VBAC controls. CONCLUSIONS: Once a woman has achieved VBAC the risk of rupture falls dramatically. The use of oxytocin, PGE2 and instrumental deliveries are additional risk factors for rupture, therefore caution should be exerted regarding their application in the presence of a uterine scar, particularly in the first vaginal birth after cesarean.
Risks of Multiple Repeat Cesareans


Obstet Gynecol. 2006 Jun;107(6):1226-32.National Institute of Child Health and Human Development Maternal-Fetal Medicine Units Network. Maternal morbidity associated with multiple repeat cesarean deliveries. Silver RM,  et al.  PMID: 16738145
...METHODS: Prospective observational cohort of 30,132 women who had cesarean delivery without labor in 19 academic centers over 4 years (1999-2002). RESULTS: There were 6,201 first (primary), 15,808 second, 6,324 third, 1,452 fourth, 258 fifth, and 89 sixth or more cesarean deliveries. The risks of placenta accreta, cystotomy, bowel injury, ureteral injury, and ileus, the need for postoperative ventilation, intensive care unit admission, hysterectomy, and blood transfusion requiring 4 or more units, and the duration of operative time and hospital stay significantly increased with increasing number of cesarean deliveries. Placenta accreta was present in 15 (0.24%), 49 (0.31%), 36 (0.57%), 31 (2.13%), 6 (2.33%), and 6 (6.74%) women undergoing their first, second, third, fourth, fifth, and sixth or more cesarean deliveries, respectively. Hysterectomy was required in 40 (0.65%) first, 67 (0.42%) second, 57 (0.90%) third, 35 (2.41%) fourth, 9 (3.49%) fifth, and 8 (8.99%) sixth or more cesarean deliveries. In the 723 women with previa, the risk for placenta accreta was 3%, 11%, 40%, 61%, and 67% for first, second, third, fourth, and fifth or more repeat cesarean deliveries, respectively. CONCLUSION: Because serious maternal morbidity increases progressively with increasing number of cesarean deliveries, the number of intended pregnancies should be considered during counseling regarding elective repeat cesarean operation versus a trial of labor and when debating the merits of elective primary cesarean delivery.

Thursday, April 19, 2018

VBAC after Cesarean for Arrest of Descent or Cephalo-Pelvic Disproportion

Your pelvis is NOT defective
A cesarean for "Arrest of Descent" means a cesarean done after a woman has dilated fully and pushed for a while without the baby descending. The amount of pushing time required for the diagnosis varies from source to source but is usually at least 1-3 hours.

When a woman has a cesarean for Arrest of Descent, she is often told something is wrong with her pelvis. She might be told she has:
  • A "flat" sacrum 
  • A "prominent" sacrum
  • A pubic arch that is "too narrow"
  • Ischial spines that are "too prominent" 
  • A pelvis that is "too small"
  • "Too much soft tissue" (fat) lining the vagina/pelvis
  • A pelvis that is the "wrong shape" 
  • A baby that was "too big" for her pelvis 
  • "Cephalo-Pelvic Disproportion" (baby too big and pelvis too small, causing baby to not fit)
Often women who have been told these things are strongly discouraged from trying for a Vaginal Birth After Cesarean (VBAC). There are documented cases where women have been told their pelvis is too flat or too small to have a VBAC, that they have "soft tissue dystocia" (a.k.a. "fat vagina"), that their pelvis is the wrong shape, or that since they couldn't push out a baby before, chances are they never will be able to because CPD is a recurring condition:
Yesterday, at my appt, while speaking with one of the midwives - she asked if I wanted her honest opinion & that if I was unable to push out a 7 and 1/2 pound baby and 2nd babies are normally larger then she didn't think it would be successful. 
The bottom line is that providers that are not truly VBAC-supportive often make women believe that something is wrong with their bodies and that they have little chance of having a vaginal birth, implying it's better just to schedule a repeat cesarean. Then the care providers conveniently have fewer VBAC labors to attend.

However, many women who have been told they have an abnormal pelvis or soft tissue dystocia or who have had a cesarean for Arrest of Descent or CPD have gone on to have VBACs anyhow.

And a new study just out confirms that many women with a prior cesarean for Arrest of Descent do indeed go on to have a VBAC and should not be discouraged from trying.

New Study on VBAC after Arrest of Descent

A recent American study (Fox 2018) shows that VBAC after prior Arrest of Descent is often successful.

In the study, one hundred women who had one prior cesarean for Arrest of Descent had a "Trial Of Labor After Cesarean" (TOLAC or TOL). A whopping 84% ended up having a VBAC. This is an excellent rate and better on average than many VBAC studies.

The authors concluded (my emphasis):
This suggests that arrest of descent is mostly dependent on factors unique to each pregnancy and not due to an inadequate pelvis or recurring conditions. Women with a prior CD [Cesarean Delivery] for arrest of descent should not be discouraged from attempting TOLAC in a subsequent pregnancy due to concerns about the likelihood of success.
The fact that the authors state this so strongly in an obstetrics journal is a big deal because it goes against what is commonly taught to many OBs, so let's reemphasize those points:
  • Arrest of Descent is NOT usually due to an inadequate pelvis
  • "CPD" is not necessarily a recurring condition
  • Women with this history should not be discouraged from trying for a VBAC
Many women can and DO have VBACs after diagnoses of CPD and Arrest of Descent. Yet strong discouragement away from VBAC is exactly what happens to many of these women, even today. 

Other Similar Studies

Was this study just a fluke? What do other studies on Arrest of Descent say?

There are only a couple of studies that specifically use the term "VBAC after Arrest of Descent" so you have widen the search a bit. Other search terms to consider include "CPD + cesarean," "cesareans after full dilation," or "cesareans done during second stage of labor" (pushing), or "prolonged second stage," or similar terms. Carefully vetted, these are essentially Arrest of Descent cesareans too.

If you just look at studies that examine VBAC after a cesarean for CPD, research reviews show that about two-thirds of women will have a VBAC. This rate is lower than for those whose first cesarean was for breech or fetal distress, but is still a very good rate. If all those women had been discouraged from VBAC or pressured into repeat cesareans, two-thirds of them would have had unnecessary cesareans!

There is very little data on women who have had more than one cesarean for CPD. However, one 1989 study did contain some data on women like this. If you crunch the data in the full text of the study, women with 2 prior cesareans for CPD had a 56% VBAC rate. So although we don't have a lot of data on this, what we do have suggests that even among women with more than one cesarean for CPD, more than half will have a VBAC.

The doctors who like to discourage VBAC cite a discouraging 1997 study that found a low VBAC rate (13%) in women who had reached full dilation and pushed in their previous labor. However, the rest of the research is much more encouraging.

In one Californian study from 2015, 54% of women with no prior vaginal birth and a prior cesarean during pushing stage went on to have a VBAC. In other words, they were just as likely to have a VBAC as not.

Similarly, a Danish study found a 59% VBAC rate in women whose cesareans occurred at 9-10 cm of dilation (9 cm often represents a fully dilated woman with a cervical lip, likely due to fetal malposition). Again, more than half had a VBAC and avoided the risks of additional surgery.

But some studies have results even better than that. In a New York study, 74.5% of women with prior pushing-stage cesareans went on to have a VBAC, some of them with forceps help, which suggests that fetal malpositions were an issue for quite a few.

Echoing those numbers is a Canadian study that found a 75% VBAC rate in those with a prior second stage dystocia cesarean. A very small, older Irish study found a 73% VBAC rate in those with a prior cesarean in the second stage.

Similarly, an older Dutch study found an 80% VBAC rate in those with a prior Arrest of Descent cesarean. This echoes our current Fox 2018 study that found an 84% VBAC rate after prior Arrest of Descent.

In summary, the majority of the research clearly supports the idea that women with a prior cesarean that occurred after full dilation and pushing can be offered a "trial of labor after cesarean" and will have a quite reasonable chance for a VBAC.

In the end, the decision whether to go for a VBAC is the mother's, but she should be reassured that she is just as likely to have a VBAC as not, and in many practices, especially with proactive care regarding fetal position, her chances are even better.

The Importance of Fetal Position

So what causes Arrest of Descent? Why does it happen in some births but not others in the same mother? The answer is usually fetal position.

In Arrest of Descent/CPD cesareans, the problem is usually the BABY'S POSITION, not the mother's pelvis.

If the baby is not well-positioned, labor tends to be slow and extra painful. It often slows or stalls between 4-7 cm of dilation. Often the mother eventually dilates fully but there is little or no progress during pushing. Fetal distress may occur.

Some providers become impatient and intervene with procedures (like breaking the waters) which may do more harm than good. Frequently, they are too quick to move to surgery when more patience might see the position resolve or the baby be born just fine in the "less-optimal" position. Recent research suggests that more than three-fourths of women with prolonged pushing stages (more than 3 hours) will deliver vaginally if just given a little more time.

What kind of fetal positions can cause problems? Read here for illustrations and specifics of the different fetal positions. The Spinning Babies website also has many helpful articles and illustrations on fetal position and how to help create maximum room in the pelvis. In the meantime, below is a brief introduction of the most common fetal malpositions.

Keep in mind that Presentation refers to which part of the baby is presenting first, and Position refers to how the baby is oriented in the mother's body in a head-down position. Also keep in mind that when describing fetal position, obstetric texts reference the back of the baby's head (the occiput) and which way the occiput is oriented in relationship to the mother. Most laypeople find it easier to understand by thinking of which way the baby is looking, so I use both in my descriptions.

Both the Spinning Babies website and The Labor Progress Handbook by Penny Simkin et al. have many ideas for various ways to help malpositioned babies resolve their position, and for creating more space in the pelvis. We will discuss this further in future posts.

Occiput Anterior (Easiest for Birth)


Occiput Anterior or OA
The easiest fetal position for labor and birth is usually Occiput Anterior. This is abbreviated OA and means the baby is head-down with the back of the baby's head against the mother's front; in other words, the baby is looking towards the mother's back. This position is considered the norm and the vast majority of babies will be born in this position.

Direct OA is when the baby is looking directly back at the mother's sacrum. LOA is when the baby is mostly facing the mother's back but his back is a bit towards the left side; ROA is the same but a bit towards the right side.

Ideally, the baby's chin is tipped towards its chest so the smallest possible diameter of its head presents. If the baby's head is not well-flexed, the presenting diameter is a bit larger. If the baby's head is tipped to one side or the other, it can be even larger. More on that below.

Occiput Posterior 


Illustration by Gail Tully, Spinning Babies
One of the most common fetal positions that can cause problems during labor is the Occiput Posterior position. This is abbreviated OP; the back of baby's head is against your back and baby is looking at your tummy. If the baby is directly facing your back, that's direct OP; if it's a little to the right or left, then that's ROP or LOP.

Although many babies enter labor in less-ideal positions like OP, only about 5% stay posterior all through labor and deliver that way. Babies that come out in the OP position are sometimes called "Stargazers" or "Sunny Side Up."

By itself, an OP position does not have to mean a cesarean, since most OP babies turn during labor and become OA before birth. The labor may be a little longer and more painful but it often proceeds just fine with a little patience. However, babies that are persistently posterior all the way through labor and birth have a high rate of problems.

Research clearly shows that persistent posterior babies have higher rates of cesareans for CPD or Arrest of Descent. This is because the presenting head diameter of a baby in OP position is larger than the baby in an OA position. In addition, the back of the baby's head is against the mother's back and that makes for a more painful labor, with lots of back labor and a slower dilation. This in turn often means lots of interventions from care providers that may make the situation worse, like breaking the waters, which takes away the cushion for baby to turn more easily and may lead to fetal distress.

However, OP babies do not always end with cesareans. With time and patience, an OP baby with a flexed head (chin to chest) can often be born vaginally. Alternatively, a vaginal birth may be possible if the care provider is patient and allows extra time for the baby's head to mold enough to descend into the pelvis. When it hits the pelvic floor, it often then rotates from OP to OA on the perineum and may be born quickly. Often an OP baby can be helped to rotate to OA through manual rotation, an instrumental delivery, or maternal postural changes like the all-fours position.

But because of the impatience of many providers, the fetal distress that can occur, and the extra-painful, longer labors associated with OP babies, many persistent OP babies end up being born by cesarean.

Deflexed Heads

If a baby's head is deflexed (not chin to chest), this can cause problems as well. A deflexed head makes the baby's presenting head diameter larger. This means the baby may not fit through very well, or the baby needs extra time for its head to mold enough to get through. OA babies with mildly deflexed heads experience longer labors, but with a little patience, are usually able to be born vaginally.

However, significant problems can occur if deflexion is extreme. Extreme examples of deflexed heads include a brow (forehead first) or face (face-first) presentation. Although vaginal births of brow and face presentations have been documented, most often they end in cesarean these days unless the baby's position can be resolved. Fortunately, brow and face presentations are quite rare.

Deflexed babies in an OP position are fairly common and result in many long, difficult labors. OP babies already start out with a larger presenting head diameter; when they also have deflexed heads (known as a "military" position), this makes the head diameter even larger. Big OP babies often have deflexed heads, making their head diameters even larger. These babies often have extremely long and hard labors, and many end in cesareans. Turn the baby around and/or tip its chin towards its chest so that the head is flexed and the baby would likely fit much better; many cesareans could be avoided.

Occiput Transverse/Transverse Arrest

Occiput Transverse, which can result
in Transverse Arrest
When a baby's head is directly sideways, facing the hip, this is called Occiput Transverse or OTOften OT positions are able to resolve to OA, but sometimes they do not and result in a vacuum extraction, forceps delivery, or cesarean.

OT often occurs when the baby was posterior earlier in labor, tries to rotate to anterior, and gets stuck in the process of turning. Sometimes it is iatrogenic (caused by the provider). If labor is slow, the care provider may break the mother's waters in an effort to speed up labor. This removes the buoyant cushion that can make it easier for the baby to finish its turn and the baby may end up "stuck" in this position. This is called "Transverse Arrest." A fair amount of cesareans are caused by transverse arrest.

Compound Presentation

A nuchal hand presenting alongside the head
Babies who have their hands up by their faces (a "nuchal hand" or sometimes a nuchal elbow/arm) can present another challenge.

The baby is basically OA and in a great position for birth, but the hand or arm beside the head causes larger-than-average presenting parts that must fit through at the same time. If the care provider can get the baby to pull back its arm/hand near birth, the baby is likely to then be born quickly. If the arm/hand remains by the baby's head, pushing is likely to be slow, painful, and difficult. Usually babies with nuchal hands can be born vaginally, but there may be quite a bit of tearing and damage to the mother. If the provider is not patient during a slow pushing stage with a nuchal hand/arm, it may result in a cesarean.

Asynclitic Heads

Asynclitic baby in OA position

Similarly, babies who have their heads tipped to the side instead of straight ("asynclitic") also have difficulty fitting. Instead of the top of the head presenting first, their parietal bone (bony side of head) presents first. The tipped head causes a larger than average head diameter that doesn't fit as easily.

Many asynclitic babies will correct the tilt of their heads if the mother's waters are kept intact and she is able to be mobile in labor. Asymmetric birth positions may help correct the tilt. Once the tilt is corrected, the baby is often born fairly quickly.

If the baby is not able to correct the tilt of its head on its own, then the care provider may be able to help through the use of a vacuum extractor or forceps. Sometimes the tilt of the head goes undiscovered or is not able to be resolved during labor; these babies often are born by cesarean.

Summary

Unfortunately, many women with a prior cesarean for CPD or Arrest of Descent are discouraged from even trying to have a VBAC. They may be told they have little chance at a VBAC and they should just schedule a planned repeat cesarean rather than risk another cesarean during labor. One woman was told:
You've already proven you can't get a baby out of your pelvis.
Obviously, that OB believed that the pelvis itself was the issue, not the baby's position, but the recent Arrest of Descent study suggests it is likely not true.

This kind of misleading "guidance" from care providers is not evidence-based. Most women with a prior CPD or Arrest of Descent cesarean who go through with labor actually have a reasonable chance at a VBAC, as this woman found:
The OB that did my c-section told me that my pelvis was small and also tilted and that because of that, a vaginal birth wouldn't be possible. Well, I...went for a VBAC anyway and it's a good thing I did because I had a wonderful amazing and natural VBAC with my next baby. And she came out in about 4 pushes. It was so easy! I had my second VBAC with my son a year ago and it went perfectly as well!
Here is a link to the story of another case where a woman who had a cesarean was told that her pelvis was too small to birth a baby and to forget about a VBAC. She went on to birth a 9 lb. baby ─ with a nuchal hand ─ as a VBAC. The Birth Without Fear blog has an awesome picture of it in their birth stories section.

That's not to say that CPD is never real. Sometimes it is. Although most cases of "CPD" are actually situational (caused by a malposition), sometimes there are rare cases of true CPD. These are usually a result of significant malnourishment in childhood, severe scoliosis, a history of rickets, or a history of a bad fall or accident where the pelvis was damaged. And sometimes, women don't have any of that in their background, really do try everything, and still end up with a cesarean because the baby just didn't fit. It does happen and it's important to acknowledge that.

But far too often, women who have had a cesarean after not being able to push out a baby are told that their pelvises are too small or defective, and they'll never be able to push out a baby. This is not true. Many women with this history can have a vaginal birth, if given an adequate chance to do so. Anecdotally, many women who have been told this benefit from having a good chiropractor evaluate their back and pelvis to help maximize the space in it and get it well-aligned. See my story below.

Women with a history of cesareans for Arrest of Descent or CPD should be offered the chance at a VBAC if they want it. Chances are good they will have one. There are never any guarantees, but research clearly shows that trying for a VBAC is a very reasonable choice in this group and should not be discouraged.

My Story

Again, many women have had cesareans for arrest of descent and yet gone on to have a VBAC. Conventional wisdom is that you need a smaller baby to get a VBAC, but some women do have VBACs with a baby even bigger than their cesarean baby. Again, fetal position is key.

This includes me. I had my first cesarean after a difficult induced labor. I dilated to 10 cm and pushed for two hours in stirrups, but ended up with a very traumatic cesarean. With my second baby, I had a relatively easy spontaneous labor where I did all the "right" things including position changes but still had FIVE HARD HOURS of pushing with little descent of my deflexed OP baby. I ended up with a second cesarean for CPD.

Both of my babies were big. I was told I had a "marginal" pelvis by my first care provider, and unless I had a smaller baby I would probably not have a vaginal birth. After my second birth, a nurse-midwife told me I probably had a pelvic shape predisposed to posterior babies and my babies would likely always be posterior. After two CPD cesareans at full dilation and after hours of pushing, I was told I was extremely unlikely to have a VBAC. The "VBAC Calculator" gave around a 20% chance of having a VBAC if I tried again.

All these declarations were wrong in the end but it was difficult to have faith. In my third pregnancy, I wavered between choosing to labor again or just going straight to a repeat cesarean. The baby was consistently posterior again all through pregnancy and I had no desire to go through a long hard labor only to end up with another cesarean ─ but neither did I want to go through another surgical recovery. I was also worried about the increase the risk of placental issues from another cesarean if I decided to have another baby in the future.

Near the end of my third pregnancy, I found a chiropractor who did a lot of work on my pelvis, including the Webster Technique and releasing the round ligaments that attach to the uterus. She felt my history of car accidents was highly relevant to the malpositions going on. According to her, the significant back and pubic pain I was having indicated "in utero constraint" that was making it hard for my babies to be in the easiest position for labor. The chiropractic adjustments eased a lot of my discomfort and the baby moved pretty quickly into a more optimal OA position for the first time in three pregnancies!

I went on to have a VBAC after 2 cesareans (VBA2C), something many providers would have told me would be extremely unlikely with my history and risk factors (short, old, "morbidly obese," big babies, two prior CPD cesareans, no prior vaginal births). Instead of pushing for 2 hours or for 5 hours as I did with my first two children, I pushed for 12 minutes with that baby. The doctor didn't even make it to the birth.

And it wasn't just a lucky fluke. Several years later, I had another VBA2C, this time with a baby that was a pound larger than either of my cesarean babies. I only pushed for 24 minutes with that baby.

Afterwards I asked my midwife to evaluate my pelvis and tell me honestly if it was truly marginal or not. She examined me and said it absolutely was not. Either the prior evaluation was wrong or chiropractic care really did create more space in my pelvis ─ or maybe a little of both. I do feel that the chiropractic care was integral to my VBACs, given that I never had an anterior baby until I had chiropractic care.

Remember, each labor and birth is unique and previous problems do not necessarily happen again.

Even a history of more than one Arrest of Descent or CPD cesarean does not mean it will continue to happen, especially if the mother is very proactive about fetal position. I had a history of TWO cesareans for Arrest of Descent and still went on to have two VBACs.

I have known women who have had VBACs after 1, 2, and even 3 prior CPD cesareans, including full dilation and pushing for hours each time with no vaginal birth. Yet they still eventually had a VBAC. The International Cesarean Awareness Network (ICAN) has a number of stories of women who have had a prior cesarean (or more) for CPD or Arrest of Descent and yet went on to have a VBAC. You can see some of them in their "Question CPD" video below.

There are never any guarantees, of course, and there are important risks to consider with both VBAC and an Elective Repeat Cesarean. However, if you choose to labor, your VBAC chances are good, anywhere between 50-80% based on the research. Don't let care providers convince you out of trying for a VBAC based on a past history of CPD or Arrest of Descent. In the end, it's your decision.



April is Cesarean Awareness Month. For more information on cesareans and VBACs, see the International Cesarean Awareness Network. 


References

J Matern Fetal Neonatal Med. 2018 Feb 27:1-5. doi: 10.1080/14767058.2018.1443069. [Epub ahead of print] Vaginal birth after a cesarean delivery for arrest of descent. Fox NS, Namath AG, Ali M, Naqvi M, Gupta S, Rebarber A. PMID: 29455594
...This was a retrospective cohort study of all patients delivered by a single MFM practice from 2005 to 2017 with a singleton pregnancy and one prior CD for arrest of descent. We estimated the rate and associated risk factors for successful VBAC. RESULTS: We included 208 patients with one prior CD for arrest of descent, 100 (48.1%) of whom attempted a trial of labor after cesarean (TOLAC) with a VBAC success rate [of] 84/100 (84%, 95% CI 76-90%). Among the women who attempted TOLAC, women with a prior vaginal delivery >24 weeks' had a significantly higher VBAC success rate (91.8% versus 71.8%, p = .01). Maternal age, body mass index, estimated fetal weight, induction of labor, and cervical dilation were not associated with a higher VBAC success rate. CONCLUSIONS: For women with a prior CD for arrest of descent, VBAC success rates are high. This suggests that arrest of descent is mostly dependent on factors unique to each pregnancy and not due to an inadequate pelvis or recurring conditions. Women with a prior CD for arrest of descent should not be discouraged from attempting TOLAC in a subsequent pregnancy due to concerns about the likelihood of success.
J Matern Fetal Neonatal Med. 2017 Feb;30(4):461-465. Epub 2016 May 5. Prolonged second stage in nulliparous with epidurals: a systematic review. Gimovsky AC, Guarente J, Berghella V. PMID: 27050812
...A systematic review of the literature was performed... for case series evaluating the morbidities of prolonged second stage of labor. Search terms used were "prolonged", "second stage", and "labor". Prolonged second stage was defined as three hours or more. Retrospective case series of prolonged second stage in nulliparous women with epidurals were identified. The primary outcome was the incidence of cesarean delivery. RESULTS: Two retrospective series with 5350 nulliparous women with prolonged second stage were identified. 76.3% (4 081/5 350) had an epidural. Of all nulliparous women with an epidural, 11.5% (4 081/35 469) had prolonged second stage. Cesarean Delivery occurred in 19.8% of these cases (782/4 081), while 80.2% had a vaginal delivery. CONCLUSIONS: Over three quarters of nulliparous women with epidural diagnosed with a prolonged second stage deliver vaginally.
VBAC After CPD Diagnosis

J Obstet Gynaecol Can. 2003 Apr;25(4):275-86. Vaginal birth after Caesarean section: review of antenatal predictors of success. Brill Y, Windrim R. PMID: 12679819
"...Even with a history of CPD, two-thirds of women will have successful VBAC, though rates decrease with increasing numbers of prior CS...There are few absolute contraindications to attempted VBAC. Attempted VBAC will be successful in the majority of attempted cases."
Obstetrics and Gynecology. February 1989. 73(2):161-5. Twice A Cesarean, Always a Cesarean? Phelan, JP et al.  PMID: 2911420
[My summary of highlights from the full text] 501 women with 2 or more previous cesareans had a TOL, and 69% had a VBAC overall. Women who had had at least one previous cesarean for CPD had a 64% VBAC rate. Those who had had 2 successive labors both ending in c/s for CPD still had a 56% VBAC rate. In other words, even those women with a previous 'failed' trial of labor had a better chance of a VBAC than another cesarean in labor.
Other Studies on Arrest of Descent or Similar Definitions
  • Am J Obstet Gynecol. 2015 Dec;213(6):861.e1-5. doi: 10.1016/j.ajog.2015.08.064. Epub 2015 Sep 6. Effect of stage of initial labor dystocia on vaginal birth after cesarean success. Lewkowitz AK, Nakagawa S, Thiet MP, Rosenstein MG. PMID: 26348381
  • Acta Obstet Gynecol Scand. 2013 Feb;92(2):193-7. doi: 10.1111/aogs.12023. Epub 2012 Nov 5. Cervical dilation at the time of cesarean section for dystocia -- effect on subsequent trial of labor. Abildgaard H, Ingerslev MD, Nickelsen C, Secher NJ. PMID: 23025257
  • Obstet Gynecol. 2001 Oct;98(4):652-5. Should we allow a trial of labor after a previous cesarean for dystocia in the second stage of labor? Bujold E, Gauthier RJ. PMID: 11576583
  • Obstet Gynecol. 2000 Apr;95(4): S38. https://doi.org/10.1016/S0029-7844(00)00660-8 Obstetrics Prognostic indicators for successful vaginal birth after cesarean delivery. Marshak J, Cooperman BS, Fried WB, Shi, Quihu. Available here.
  • Br J Obstet Gynaecol. 1998 Oct;105(10):1079-81. Vaginal delivery after previous caesarean section for failure of second stage of labour. Jongen VH, Halfwerk MG, Brouwer WK. PMID: 9800930
  • Obstet Gynecol. 1998 Nov;92(5):799-803. First delivery after cesarean delivery for strictly defined cephalopelvic disproportion. Impey L, O'Herlihy C. PMID: 9794672
  • Obstet Gynecol. 1997 Apr;89(4):591-3. Correlation between maximum cervical dilatation at cesarean delivery and subsequent vaginal birth after cesarean delivery. Hoskins IA, Gomez JL. PMID: 9083318

Saturday, March 24, 2018

Timing of Elective Cesareans in High BMI Women


Doctors do far too many cesareans in high BMI women, especially planned "elective" cesareans without labor. Many of these cesareans are unnecessary and place women of size and their babies at risk. Research shows that about one-third or more of all cesareans done on high BMI women are planned, pre-labor cesareans done on moms who were never even given a chance to labor.

But sometimes cesareans are truly needed, even a planned, non-labor cesarean. And sometimes an elective repeat cesarean is chosen by women. When a planned cesarean happens, it's important not to do it sooner than absolutely necessary.

Labor helps babies prepare for breathing on their own. When a cesarean is done without labor, the baby often has more difficulty establishing breathing on its own. The earlier the cesarean is done, the higher the risk for breathing problems. Therefore, most obstetric guidelines now suggest not doing an elective cesarean before 39 weeks. If a cesarean is medically needed before then, then corticosteroids are usually used to mature the fetal lungs for a while before the cesarean is done.

Recent research on the CDC database now suggests that the 39 week benchmark for planned cesareans is even more important in "obese" women. 

The babies of high BMI women in the study were particularly prone to the need for assisted ventilation (help breathing) and treatment in the Neonatal Intensive Care Unit (NICU). A dose-dependent relationship was seen between BMI and need for assisted ventilation, and this was not modified by use of corticosteroids.

One underappreciated reason for this is that many women of size have longer menstrual cycles than average-sized women. Instead of 28 days, many have menstrual cycles of 35 days or longer. That means that when their babies are delivered at what is thought to be 39 weeks, the babies are really only 38 weeks (or even younger). As a result, their lungs are less mature and less ready to function on their own. No wonder they needed more ventilation and more NICU time!

To improve outcomes in obese women and their babies, care providers should seek to adjust women's due dates to reflect the length of their menstrual cycles, or to have an extremely accurate dating ultrasound early in the pregnancy. And unless there is a critical need to deliver earlier, planned elective cesareans should be held off until between 39 or preferably 40 weeks, especially for those with longer cycles.

It's important to keep pushing doctors to do fewer planned elective non-labor cesareans in obese women; far too many are being done these days. They should be saved for truly necessary situations. But when a planned non-labor cesarean is done, it is critical not to schedule it too soon in order to lessen the risk of breathing complications in the baby.

More attention needs to be paid to ensuring accurate pregnancy dating in women of size. This can be done either by adjusting the due date to reflect the woman's cycle length, or by doing a dating ultrasound early in pregnancy (first trimester), or a combination of both.



References

J Perinat Med. 2018 Mar 15. pii: /j/jpme.ahead-of-print/jpm-2017-0384/jpm-2017-0384.xml. doi: 10.1515/jpm-2017-0384. [Epub ahead of print] Effect of pre-pregnancy body mass index on respiratory-related neonatal outcomes in women undergoing elective cesarean prior to 39 weeks. Vincent S, Czuzoj-Shulman N, Spence AR, Abenhaim HA. PMID: 29543593
OBJECTIVE: To examine the association between pre-pregnancy body mass index (BMI) and neonatal respiratory-related outcomes among women who underwent an elective cesarean section (CS). METHODS: A retrospective cohort study was conducted using the Centers for Disease Control and Prevention (CDC)'s 2009-2013 period linked birth/infant death dataset. Women who had elective CSs at term were categorized by their pre-pregnancy BMI as normal, overweight, obese or morbidly obese...A dose-dependent relationship between maternal pre-pregnancy BMI and assisted ventilation was seen. Furthermore, infants born to morbidly obese women were at significantly increased risk for assisted ventilation over 6 h (OR 1.24, 95% CI 1.15-1.35) and admission to intensive care units (OR 1.17, 95% CI 1.13-1.21). Infant mortality rates were 4.2/1000 births for normal weight women, and 5.5/1000 births among the morbidly obese group (OR 1.43, 95% CI 1.25-1.64). Risk for adverse outcomes was increased with elective SC performed at earlier gestational age, and this effect was not modified by use of corticosteroids. CONCLUSION: Overweight and obese women are at particularly greater risk of adverse newborn outcomes when elective CSs are done before 39 weeks. In these women, elective CSs should be delayed until 39 weeks, as corticosteroid use did not eliminate this association.
Obstet Gynecol. 2017 Nov;130(5):994-1000. doi: 10.1097/AOG.0000000000002257. Trial of Labor Compared With Cesarean Delivery in Superobese Women. Grasch JL, Thompson JL, Newton JM, Zhai AW, Osmundson SS. PMID: 29016512
We conducted a retrospective cohort study of all women with body mass indexes (BMIs) at delivery of 50 or greater delivering a live fetus at 34 weeks of gestation of greater between January 1, 2008, and December 31, 2015...RESULTS: There were 344 women with BMIs of 50 or greater who met eligibility criteria, of whom 201 (58%) labored and 143 (42%) underwent planned cesarean delivery...CONCLUSION: Despite high rates of cesarean delivery in women with superobesity, labor is associated with lower composite maternal and neonatal morbidity. Severe maternal morbidity may be higher in women who require a cesarean delivery after labor.
Epidemiology. 2002 Nov;13(6):668-74. Influence of medical conditions and lifestyle factors on the menstrual cycle. Rowland AS, Baird DD, Long S, Wegienka G, Harlow SD, Alavanja M, Sandler DP. PMID: 12410008
...We analyzed cross-sectional data collected from 3941 premenopausal women from Iowa or North Carolina participating in the Agricultural Health Study between 1994 and 1996. Eligible women were age 21-40, not taking oral contraceptives, and not currently pregnant or breast feeding. We examined four menstrual cycle patterns: short cycles (24 days or less), long cycles (36 days or more), irregular cycles, and intermenstrual bleeding. RESULTS: Long and irregular cycles were less common with advancing age and more common with menarche after age 14, with depression, and with increasing body mass index. The adjusted odds of long cycles increased with increasing body mass index, reaching 5.4 (95% confidence interval [CI] = 2.1-13.7) among women with body mass indexes of 35 or higher compared with the reference category (body mass index of 22-23)....

Sunday, February 11, 2018

Cinderella VBACs and Gestational Age

Image: Disney

"At my last doctors appointment I went in and asked my doctor if I could continue with the pregnancy past 40 weeks if I were still pregnant. He said No because the risk of uterine rupture goes up past 40 weeks."  source
"Gestational age greater than 40 weeks alone should not preclude Trial of Labor After Cesarean." ACOG 
Many women planning a VBAC (Vaginal Birth After Cesarean) are told by their providers that they will be supported for a VBAC, but their doctors often conveniently forget to mention ahead of time that they enforce arbitrary rules that require women to go into labor by 40 weeks or be forced into a cesarean, like the woman quoted above. Some even insist on a repeat cesarean by 39 weeks.

This is what author Henci Goer calls a "Cinderella VBAC." The doctor claims to support VBACs, but puts so many limits on VBAC labors that almost no one gets one. Examples: the mother must go into labor before 40 weeks, the baby has to be below a certain weight, the mother must not gain very much weight in pregnancy, etc.

In that way, caregivers can give lip service to supporting VBACs without having to actually attend very many. As a result, activists separate caregivers into "VBAC Tolerant" versus truly "VBAC-friendly" by their insistence on these type of Cinderella VBAC restrictions.

Gestational Age Cutoffs in VBACs

One of the most common Cinderella VBAC rules is a gestational age cutoff. At 40 weeks, many women are told the risk for uterine rupture goes up so a VBAC labor would be too risky and they must schedule a repeat cesarean. However the research on uterine rupture past 40 or 41 weeks is conflicting and women are not being permitted to make fully informed decisions.

Some studies do show a modest increase in rupture risk by gestational age. However, others do not. One of the largest and most powerful gestational age studies did not show a statistically increased risk of rupture past the due date. This study was done at 17 different hospital centers, over a period of 5 years, and involved 11,587 women who labored for a VBAC.

What muddies the research waters is that many pregnancies after the due date end up induced, and a number of studies show that induction of VBACs is associated with more uterine rupture. So are the ruptures in these studies truly being caused by going beyond the due date, or is it an artifact of the high rate of inductions and augmentations done in pregnancies after 40 weeks? Some studies control for this and others do not.

In their book, Optimal Care in Childbirth (pg. 118), Henci Goer and Certified Nurse-Midwife Amy Romano note that the majority of uterine ruptures in these gestational age studies are found in the induced groups, and especially in those induced with an unfavorable cervix.

Now there is a new study just out on gestational age and rupture. It also found that the risk for uterine rupture did NOT increase with gestational age.

In this seven-year Israeli study of 2,849 women, 0.56% of women had a uterine rupture during a "trial of labor after cesarean" (TOLAC). The rate did not differ significantly by gestational age (GA), and  90% of women in the study had a VBAC. If all the women at 40 weeks had been forced to have a repeat cesarean, that would have been a lot of unnecessary cesareans. This study adds strong support to the position that women should not have to have a repeat cesarean at 40 weeks. The authors conclude:
Among women at term with a single previous cesarean delivery, GA at delivery was not found to be an independent risk factor for TOLAC success or uterine rupture. We suggest that GA by itself will not serve as an argument for or against TOLAC.
The latest guidelines from ACOG (the American College of Obstetricians and Gynecologists) note that gestational age beyond 40 weeks should not preclude laboring for a VBAC. This position is echoed by VBAC guidelines from other countries as well.

What About Inductions?

What about other options? To avoid going past 40-41 weeks yet still give the woman an opportunity at a VBAC, some caregivers will induce labor around the due date. They point out that in some studies the chance of a VBAC decreases after the due date so they hope that inducing at the due date gives the woman the best chance at a VBAC. They also point out that the risk for stillbirth, although quite low, does increase at some point after the due date.

However, induction at term has pros and cons. In most studies (but not all) induction of labor increases the risk for uterine rupture and decreases the chance of a VBAC. For example, the 2015 NICE guidelines from the Royal College of Obstetricians and Gynaecologists states:
Women should be informed of the two- to three-fold increased risk of uterine rupture and around 1.5-fold increased risk of caesarean delivery in induced and/or augmented labour compared with spontaneous VBAC labour.
In Optimal Care in Childbirth (pg. 118), Goer and Romano, noting that the majority of rupture cases that occurred after the due date were associated with induction, state:
These data suggest that women should not be induced for passing their due date. Induction both increases their risk of scar rupture and decreases the likelihood of VBAC. 
But how does induction of labor specifically compare with expectant management past the due date in VBAC women?  Recent research suggests that induction increases the risk for uterine rupture (1.4%) as opposed to expectant management (0.5%). In other words, caregivers' interventive management of women past the due date actually increased the risk for harm, not reduced it.

This is not to say that induction and augmentation should never be used in VBAC labors. Sometimes induction is medically necessary. Used carefully, induction and augmentation can be used safely in some VBAC labors. It doesn't have to be all or nothing.

Some types of VBAC inductions probably carry more risk than others, though. Some research suggests that prostaglandin use, sequential use of prostaglandins and pitocin, the induction of women with an unripe cervix, and the induction of women without a prior vaginal birth may raise the risk for uterine rupture.

For sure, misoprostol (PGE1) is associated with much higher uterine rupture rates and should never be used to induce a woman with a prior cesarean. The risk with other prostaglandins (PGE2) is less clear, though most clinicians avoid them these days.

Currently, the most favored method for inducing a VBAC is by mechanical means, such as amniotomy (breaking the waters) or a transcervical balloon catheter, along with oxytocin augmentation if needed. These methods may be less risky than other methods of induction for VBAC moms, although they still carry more risk for uterine rupture than spontaneous labor.

In other words, all induction scenarios do not carry equal risk. The risks may not be as high for induced labors in women with a very ripe cervix or with a prior vaginal birth, but parents should remember that the risk is never zero.

Although induction tends to lower the probability of having a VBAC, many women are induced and do have VBACs. This seems especially true for women with a high Bishop's Score (indicating a ripe cervix) or a previous vaginal birth. Regardless, the majority of women who have been induced do have VBACs. In several recent studies, about one-half to two-thirds of induced labors ended in VBAC. That's a lot of repeat cesareans averted.

Induction is a decision that should not be taken casually but which can be a legitimate choice for some. However, induction is generally overused in VBAC labors, and is often undertaken without fully apprising women of the risks associated with it. But it does remain a viable choice and there are women who have had induced VBACs.

Summary

When a woman with a prior cesarean passes her due date, there are many courses of action that are possible. Every choice has benefits and risks. Although the vast majority of women with a prior cesarean will have good outcomes whatever they choose, there are unique pros and cons to consider.

The most logical choice is to let nature take its course and wait for spontaneous labor. Many caregivers are very supportive of waiting for spontaneous labor after 40 weeks in women with a prior cesarean, and many will wait until after 41 weeks or even later to start discussing alternatives, as long as mother and baby are doing well. Obviously, each case's unique circumstances must be considered.

On the other hand, a surprising number of caregivers still use gestational age restrictions and force either repeat cesarean or induction at 40 weeks. For some, this is out of fear of any possibility of increased risk of rupture or a fear of stillbirth. For others, it is out of a mistaken belief that after 40 weeks, there is little chance of a VBAC. A cynic would also note that since about half of women do not go into labor before their due date, gestational age restrictions also mean that doctors attend fewer VBAC labors, easing their schedules while still letting them appear to be supportive of VBACs.

Unfortunately, research does not offer 100% clear guidance on uterine rupture risk after 40 weeks. Some research suggests a somewhat increased risk, but a closer look suggests the risk is mostly in induced labors or the difference is quite modest. The strongest research does not show an increased risk after the due date at all.

Gestational age restrictions also bring up the question of ethics. Mandating a repeat cesarean or an induction at a certain gestational age is a high-handed and paternalistic approach. It infantalizes women and strips them of their autonomy to make their own medical decisions. It also ignores the possible harms associated with these interventions.

Instead, women should be counseled about the pros and cons of each choice. Caregivers may advise a certain course of action, but in the end the woman has the right to accept or refuse that course of action. Discussion of these issues should begin early in pregnancy, not at term, so there is plenty of time for decision-making. Remember, every choice has pros and cons.

Repeat Cesarean
without labor
Pros: Convenience of scheduling; lowest risk for rupture; no uncertainty of labor
Cons: All the risks of surgery and surgical recovery (bleeding, pain, infection, blood clots); more breathing problems for the baby; more breastfeeding problems; substantial risk of life-threatening placental issues in future pregnancies
Expectant Management past due date
Pros: Spontaneous labor is usually easier/less painful and VBAC is more likely; baby is more ready for life outside the womb (less problems with breathing, breastfeeding, blood sugar levels, bilirubin levels); mother usually has an easier recovery
Cons: May labor and still end up with a cesarean; continuing the pregnancy entails the very small but real risk of stillbirth or uterine rupture; may still need to have induction of labor at some point, may have decreased chance of a VBAC (although this may be influenced by high induction rates later)
Induction of Labor at 40 or 41 weeks
Pros: Induction can be scheduled and planned for; most of the time induction still ends in a VBAC; induction means predictable staffing requirements for the hospital
Cons: Induction involves a harder labor and more need for pain relief; more risk for fetal distress; a significantly increased risk for uterine rupture; and typically a decreased chance for a VBAC. May still end up with another cesarean after labor
Clearly, there are no easy answers. No one answer is the right answer for all women and situations.

The most important take away here is that after the due date, women with a prior cesarean should not be forced into anything; they should have choices. The pros and cons of the various choices should be reviewed with the mother and the ultimate choice should be left up to her. 

At term, some women will choose repeat cesarean, some will choose induction, and some will choose to wait for spontaneous labor. All are valid choices.

The ACOG guidelines are clear and caregivers need to honor them. Gestational age past 40 weeks should not be used as a cut-off to keep women from laboring for a VBAC.

Women who want a VBAC should ask careful questions early in pregnancy about the guidelines of their providers, including whether there are gestational age cutoffs or other limitations on their options. Be proactive; don't wait until the last minute to find out. In some cases, women may need to switch providers in order to get a truly VBAC-friendly provider. It is possible to do so, even late in pregnancy, but the process is easiest when it's done early.

The time is at hand. All women deserve to go to the ball if they want to. "Cinderella VBACs" need to become a thing of the past.

Checklist originally from Melek Speros


References

Arch Gynecol Obstet. 2018 Jan 22. doi: 10.1007/s00404-018-4677-9. [Epub ahead of print] Trial of labor following one previous cesarean delivery: the effect of gestational age. Ram M, Hiersch L, Ashwal E, Nassie D, Lavie A, Yogev Y, Aviram A. PMID: 29356955
PURPOSE: To stratify maternal and neonatal outcomes of trials of labor after previous cesarean delivery (TOLAC) by gestational age. METHODS: Retrospective cohort study of all singleton pregnancies with one previous cesarean delivery in TOLAC at term between 2007 and 2014. We compared outcomes of delivery at an index gestational week, with outcomes of women who remained undelivered at this index gestational week (ongoing pregnancy). Odds ratios and 95% confidence intervals were adjusted for maternal age, previous vaginal delivery, induction of labor, epidural use, presence of meconium, and birth weight > 4000 g. RESULTS: Overall, 2849 women were eligible for analysis. Of those, 2584 (90.7%) had a successful TOLAC and 16 women (0.56%) had uterine rupture. Those rates did not differ significantly for any gestational age (GA) group. Following adjustment for possible confounders, GA was not found to be independently associated with adverse maternal or neonatal outcomes. CONCLUSION: Among women at term with a single previous cesarean delivery, GA at delivery was not found to be an independent risk factor for TOLAC success or uterine rupture. We suggest that GA by itself will not serve as an argument for or against TOLAC.
Obstet Gynecol. 2005 Oct;106(4):700-6. Safety and efficacy of vaginal birth after cesarean attempts at or beyond 40 weeks of gestation. Coassolo KM, Stamilio DM, ParĂ© E, Peipert JF, Stevens E, Nelson DB, Macones GA. PMID: 16199624 
OBJECTIVE: To compare rates of vaginal birth after cesarean (VBAC) failure and major complications in women attempting VBAC before and after the estimated date of delivery (EDD) METHODS: This was a 5-year retrospective cohort study in 17 university and community hospitals of women with at least 1 prior cesarean delivery. Women who attempted VBAC before the EDD were compared with those at or beyond 40 weeks of gestation. Logistic regression analyses were performed to assess the relationship between delivery beyond the EDD and VBAC failure or complication rate. RESULTS: A total of 11,587 women in the cohort attempted VBAC. Women past 40 weeks of gestation were more likely to have a failed VBAC. After controlling for confounders, the increased risk of a failed VBAC beyond 40 weeks remained significant (31.3% compared with 22.2%, odds ratio 1.36, 95% confidence interval 1.24-1.50). The risk of uterine rupture (1.1% compared with 1.0%) or overall morbidity (2.7% compared with 2.1%) was not significantly increased in the women attempting VBAC beyond the EDD. When the cohort was defined as 41 weeks or more of gestation, the risk of a failed VBAC was again significantly increased (35.4% compared with 24.3%, odds ratio 1.35, 95% confidence interval 1.20-1.53), but the risk of uterine rupture or overall morbidity was not increased. CONCLUSION: Women beyond 40 weeks of gestation can safely attempt VBAC, although the risk of VBAC failure is increased.