Tuesday, May 1, 2012

Supersized Women and Cesareans: A Tale of Two Cities

Although most care providers mean well when caring for high-BMI women, one consistent blind spot has been providers recognizing how the  high level of interventions used with many high-BMI women influence outcome.

In other words, are poor outcomes only due to "obesity" or do some poor outcomes reflect the interventive way that obese women are often managed in pregnancy and birth?

This is a particularly relevant question for the high cesarean rates found in "morbidly obese" women (BMI of 40 or more).  If a high-BMI woman is perceived as ultra high-risk, and is therefore subjected to increased rates of interventions (like inductions, early epidurals, and a lower threshold for surgery), does the resulting high cesarean rate really reflect problems with obesity itself, or with the way obese women are managed?

Here are two studies of cesarean rates in women of size that demonstrate that iatrogenic (provider-caused) influences can have a very strong effect on cesarean rates, and that a high cesarean rate in morbidly obese women is NOT just about the obesity itself.

These two studies examined cesarean rates in "super obese" women (BMI of 50 or more), one from Kentucky and one from the U.K.  The Kentucky study found a super-high c-section rate, and the U.K. study did not.

Yet the two studies basically were looking at very similar study groups, women with a BMI of 50 or more. If cesarean rates really are tightly tied to obesity and obesity alone, shouldn't the cesarean rates in these two studies be similar?

In the Kentucky study, women with a BMI over 50 had a whopping 56% cesarean rate. Compare that with the British study that found a 30% cesarean rate in women with a BMI over 50.

The Kentucky cesarean rate was nearly DOUBLE the rate of the British group, even though the size of the women was similar. 

This strongly suggests that management of labor around the pregnancies of supersized women differed and highly influenced the resulting cesarean rate, and that it's NOT just about a woman's size, but also her care provider's management.

We can't tell for sure from these particular studies why the cesarean rates in women of size in these two places are so different, but it's a good bet that it's NOT because the uteri of British women are that much more efficient than those of Kentucky women. No, the contrast in rates is much more likely to be due to differences in care, attitudes, and interventions.

A couple of strong possibilities spring to mind.

First, midwives are the most prevalent form of care provider for most women in the U.K., whereas most women in the USA get their care from OBs.  Research shows that on the whole, midwives tend to have lower cesarean rates, even when the risk profiles of patients are similar.  So perhaps the cesarean rate is lower because more of the "super obese" women in the U.K. had access to midwifery care.  If so, this is yet another reason to be alarmed about the move towards restricting fat women's access to lower-tech birthing alternatives and midwifery care.

Second, we don't know that much about the types of intervention, induction rates, and threshold for surgical intervention in each study.  My guess is that the Kentucky study had very high induction rates (which tends to lead to higher cesarean rates), a higher rate of interventions, and a lower threshold for doing a cesarean in labor.

I would love to see more research that focuses on why there can be such different outcomes in "morbidly obese" women.  We need to really shine a spotlight on differing management protocols and how they impact cesarean rates ─ and particularly so in women of size.

Interestingly, the Kentucky study notes that pitocin augmentation in labor led to lower cesarean rates in these women, although this difference did not rise to statistical significance.  They speculated, therefore, that "a qualitative or quantitative deficiency in the hormonal regulation of labor exists in the morbidly obese parturient."

This is a theory that is often bandied about in obstetric research (without any supporting proof, but often accepted as gospel anyhow). Yet if this were true, why were 70% of British women able to birth vaginally? It's far too easy and convenient to blame fat women's hormones instead of looking more closely at your own management practices instead.

It's time for doctors to stop scapegoating obesity alone for high cesarean rates in women of size, and long past time for them to start examining more closely how their own biases and high-intervention protocols negatively influence outcomes in this group.

This is not an emotionally comfortable thing to study, because care providers are human and no one wants to acknowledge that their own biases and management can affect outcome so strongly.  I understand that.

But if care providers are truly interested in improving outcomes in "obese" women, then this is the kind of work that MUST be done.  

The contrast between these studies shows that most very fat women CAN give birth vaginally....if caregivers would just stand aside and let them. It's time to take off the blinders and see how management protocols can  influence that.


Am J Perinatol.  2011 Jun 9. [Epub ahead of print] Extreme Morbid Obesity and Labor Outcome in Nulliparous Women at Term.  Garabedian MJ, Williams CM, Pearce CF, Lain KY, Hansen WF.  PMID: 21660900

Source: Department of Obstetrics and Gynecology, University of Kentucky, Lexington, Kentucky.
We examined the prevalence of cesarean delivery (CD) among women with morbid obesity and extreme morbid obesity. Using Kentucky birth certificate data, a cross-sectional analysis of nulliparous singleton gestations at term was performed. We examined the prevalence of CD by body mass index (BMI; in kg/m (2)) using the National Institutes of Health/World Health Organization schema and a modified schema that separates extreme morbid obesity (BMI ≥50) from morbid obesity (BMI ≥40 to less than 50). Bivariate and multivariate analyses were performed. Multivariate modeling controlled for maternal age, estimated gestational age, birth weight, diabetes, and hypertensive disorders. Overall, 83,278 deliveries were analyzed.

CD was most common among women with a prepregnancy BMI ≥50 (56.1%, 95% confidence interval 50.9 to 61.4%). Extreme morbid obesity was most strongly associated with CD (adjusted odds ratio 4.99, 95% confidence interval 4.00 to 6.22).

Labor augmentation decreased the likelihood of CD among women with extreme morbid obesity, but this failed to reach statistical significance. We speculate a qualitative or quantitative deficiency in the hormonal regulation of labor exists in the morbidly obese parturient. More research is needed to better understand the influence of morbid obesity on labor.
BJOG. 2011 Mar;118(4):480-7. Planned vaginal delivery or planned caesarean delivery in women with extreme obesity. Homer CS, Kurinczuk JJ, Spark P, Brocklehurst P, Knight M.  PMID: 21244616

Source: National Perinatal Epidemiology Unit, University of Oxford, UK.
OBJECTIVE: To compare the outcomes of planned vaginal versus planned caesarean delivery in a cohort of extremely obese women (body mass index ≥ 50 kg/m(2)). 
DESIGN: A national cohort study using the UK Obstetric Surveillance System (UKOSS). 
SETTING: All hospitals with consultant-led maternity units in the UK. 
POPULATION: Five hundred and ninety-one extremely obese women delivering in the UK between September 2007 and August 2008. 
METHODS: Prospective cohort identification through UKOSS routine monthly mailings. 
MAIN OUTCOME MEASURES: Anaesthetic, postnatal and neonatal complication rates. 
RESULTS: After adjustment, there were no significant differences in anaesthetic, postnatal or neonatal complications between women with planned vaginal delivery and planned caesarean delivery, with the exception of shoulder dystocia (3% versus 0%, P = 0.019). There were no significant differences in any outcomes in the subgroup of women who had no identified medical or antenatal complications. 
CONCLUSIONS: This study does not provide evidence to support a routine policy of caesarean delivery for extremely obese women on the basis of concern about higher rates of delivery complications, but does support a policy of individualised decision-making on the mode of delivery based on a thorough assessment of potential risk factors for poor delivery outcomes.


Janie said...

hmmmmm so it is true, how our providers think about us affects our care... why don't people understand that?

Tilly Cat & Pip-Squeak said...

Very interesting. To be fair though, although I do believe midwives are preferable to OBs during labour in most cases, midwives in the UK are a very different beast to midwives in the USA (much more part of the system.) It *may* be that a bigger factor in the lower c/section and intervention rate in the UK vs the USA is the fact that more medicalised births (and c-sections) cost the NHS a lot more. But it's all good, since the end result is better anyway ;)

Incidentally, if you (or anyone else that can help) read this, I am a woman with a BMI over 50, going through my 3rd pregnancy. My first 2 births were natural, full term and very good waterbirths, however this time around I'm facing having to be induced early due to some issues with the baby (nothing to do with my BMI.) These issues the baby is having are meaning that I'm looking at an induction with what will possibly be an unripe cervix and limited mobility due to the need for continuous monitoring. I am well aware of the pitfalls ahead of me :( so any advice on what I could do to possibly improve the experience and outcome while working with this situation will be very gratefully received... You can contact me privately if you prefer, I'm abadop, to be found at the old yahoo com place ;)

Well-Rounded Mama said...

Tilly Cat, I'm sorry to hear your new baby is having issues that will require inducing early. That's a whole set of different worries, isn't it? Hugs.

If you've had two prior vaginal births, your chances for a vaginal birth despite this being an induction are good. Still somewhat elevated because of inducing, but prior vaginal births really ups your chances. Your body knows how to do this.

If this will have to be done before your cervix is likely to be ripe and the baby's situation really does necessitate early delivery, acupuncture is one way to start ripening things ahead of time. Not a sure guarantee, but with enough lead time it can help some women. Just be sure you really do need to deliver by xxx date before you start. It can help start turning "on" the oxytocin etc. receptors in the body, so they are more ready to let the induction work when it happens.

Well-Rounded Mama said...

Tilly Cat, a few more hints on maximizing your chances with induction.

An unmedicated induction is possible, but it's not easy. My advice to women is to by all means last as long as possible going natural, but if you find that you need an epidural, don't be afraid to use it. Induced labor is much harder generally than normal labor; this is the sort of situation where an epidural can be a real gift. But lasting as long as you can FIRST while staying mobile as you can manage (even with continuous monitoring, some mobility is possible) is advantageous.

Having a doula is also helpful. One very small study (insert caveats) found that women undergoing induction for medical reasons had much higher CS rates if they didn't have a doula. Just be sure you hire one that won't judge you if you feel you need an epidural at some point, and one who knows tricks to help you maximize your chances even if you need an epidural.

Laboring down (not pushing just because you've reached 10cm but letting your body have time to NEED to push before you start active pushing efforts) has been shown in research to be helpful if you do end up with an epidural.

I do know women who have done an induction without an epidural; I'm not telling you it's impossible. A lot depends on how ready your body is and if the baby is in a good position. But I am saying that inductions are generally much harder than a normal, spontaneous labor, so don't be afraid to use an epidural if you get to the point where you think you'll need it. Be flexible and open to listening to your own needs.

Careful attention to fetal position is very important. Make sure your midwife or consultant has some training in fetal repositioning techniques if possible. See a chiropractor or osteopath regularly to increase the chances of a well-positioned baby when you do need to labor.

Not letting them break your water too early is also helpful. Keeps that cushion of waters in place to protect against infection, and helps the baby turn more easily if the position is less than optimal.

Hope that gives you a few hints to help. Many best wishes to you. I hope all turns out well.

Tilly Cat & Pip-Squeak said...

Thanks WRM, this is very helpful. I do have a doula I was going to use and one of her own births was an induction, so hopefully it will help. Re the not breaking my waters too early, the progression they use here is pessary -if this doesn't send you in full blown labour after a few applications then break waters, -if labour not started in a couple of hours then drip. Are you recommending that I request the drip being used prior to/instead of them breaking my waters? Just a bit unclear... :)
I'm seeing an osteopath today for spd so I'll ask her about positioning and see about an accupuncturist too, thanks for those tips. Would starting EPO early (vaginally maybe?) be a good idea? I'm 34.5 weeks now.

Elizabeth said...

Tilly Cat & Pip-Squeak, I think that you make a really good point about how there's less of a financial incentive for women using the NHS to have a c-section for their medical providers, since they're not going to be getting anything extra from the woman if she has an unmedicated vaginal birth versus a c-section.
My husband is in the US Air Force so our medical insurance is actually a government benefit with little to no out of pocket costs to us. Our daughter was born by c-section in a civilian hospital (his current base isn't big enough to support a hospital) so my OB and the hospital did receive more money than they would have if I'd had the natural vaginal birth I'd wanted. Since her birth I've spent a lot of time researching VBACs, and I've found that in the US (foreign US military base hospitals apparently tend to have bans) women are more likely to succeed at a base hospital. In large part because Tricare (military insurance) doesn't pay military medical facilities, so there's no incentive to perform a more expensive delivery since they aren't going to get extra.

Congratulations on your new little one, and hopefully everything will go wonderfully with their birth!

Well-Rounded Mama said...

Tilly Cat, I should remind you I'm not a medical professional, so I would suggest you discuss this carefully with your provider and consider all the pros and cons.

My own personal opinion is that I would choose to do the drip before having my water broken. Research shows that breaking the water speeds labor only by an hour or so, and opens you up to a potential route of infection. Some research also suggests that breaking the water early in labor increases the chances of a cesarean. And it takes away the cushion for baby to change its position if it's slightly malpositioned.

Sometimes breaking the water can put you in full labor without having to resort to a drip, so that's why they do it. But most often, it doesn't end up putting you in full labor and a drip is needed anyhow, plus you are now on the clock for infection watch. So I personally would choose a drip first and avoid breaking the water.

Also, you can induce longer if your waters are intact. Some providers are open to sequential induction; if you don't make a lot of progress the first day, they will stop the induction and try again the next day or two. Once the water is broken, though, this is no longer an option. You are on a clock and they generally want you delivered within around 24 hours or so because of the potential for infection.

That's not to say that it's never appropriate to break the waters. If external monitoring is just not working well enough for you due to your size or baby's position, an internal monitor (which requires breaking the waters) can be helpful. However, that potential for infection is there, so I always suggest that women decline routine ROM, and only use it when it's clearly needed.

Another reason is that labor is typically much more painful once the water is broken, especially induced labor. It's okay to get an epidural if you need one, but better to do what you can to avoid needing one when possible.

Everything in medicine has pros and cons. Breaking the water offers some advantages (can put you in labor without the drip, can speed up labor somewhat, enables the use of an internal monitor), but my personal opinion is that the disadvantages are greater (increased risk for infection, possible increased risk for CS, baby can't easily change its position if needed, harder to tolerate labor without an epidural, potential for prolapsed cord or fetal distress, etc.).

However, as always, you have to evaluate these decisions for your own situation and be flexible to changes in plans as things develop. Remember that these things are your choice, and you have the right to refuse interventions, even if it goes against typical induction protocol in your hospital. OTOH, if you feel it's right for you, don't feel constrained by someone on the internet cautioning you. It's your baby and your decision. These are dynamic situations and you have to do what seems best to you at the time.

Willow said...

Oh, Kmom, how I love you. I've missed you. Thank you!!

Tilly Cat & Pip-Squeak said...

Thank you, I appreciate this, lots of things to discuss with my providers :)

And thanks for well wishes, I'll make sure I let everyone know how it all turns out in a few weeks. (I've been reading this blog for a couple of years now!)

Anonymous said...

My doctor gave me the choice. Even though I had an emergency one 12 years ago, she said it was totally up to me and I am towards the high 40's in BMI. I was never told I would probably have to have one. I did end up with a hernia from a shitty surgery a year ago and will need to have a csection this time because of that but I'm okay with it.