Timing of Planned Cesareans

As we have discussed before, cesareans are at epidemic level among "obese" women. Although rates vary from study to study, on average up to one-half of all "morbidly obese" women today give birth by cesarean, many of them planned (done before labor). In some areas and hospitals, the rate approaches three-quarters.

[Of course, the c-section rate does NOT need to be that high in women of size, but because of current practice patterns, it is skyrocketing. For more on this topic, read this.]

This is a travesty because surgery is riskier on larger people; more problems with anesthesia, more risk of infection, hemorrhage, blood clots, and wound complications. And cesareans have long-term health implications for women of all sizes, both for future pregnancies and the woman's own health.

But let's leave that for another rant and talk instead about the timing of planned cesareans, and why this is such an important issue, particularly for women of size.

Timing Is Everything

A woman's "due date" is about 40 weeks, and a "full-term" pregnancy is anywhere from 37 to 42 weeks. If, for whatever reason, an "elective" cesarean is planned, what is the most favorable time for scheduling that surgery?

Many doctors in recent years have been scheduling cesareans early. A repeat c-section at 38 weeks is routine in many communities, and 37 is not unheard of. Sometimes, women themselves advocate for a little early because they are uncomfortable and "tired of being pregnant."

Doctors, too, often want to "just get things over with" and get that patient off their books. Scheduling a c-section at 38 weeks means two less appointments cluttering up their busy schedules. They also have talked themselves into believing that scheduling a little early might prevent a few unexpected stillbirths at term (even though that risk is extremely low and outweighed by the risks of being born early).

So, over time, doctors decided that "term is term" and a few more days doesn't make an appreciable difference in the baby's condition.

However, new research shows that planned cesareans should not be performed prior to 39 weeks at the earliest.

The Benefits of Waiting

Before 39 weeks, the risk of breathing difficulties in the baby is quite a bit higher. The older the baby is, the more ready they are to breathe on their own.

In addition, younger babies have more difficulties regulating their blood sugar, have more jaundice, and have more difficulties learning to breastfeed. But it's the breathing difficulties that puts the babies most at risk.

In particular, cesareans without labor put babies at much higher risk for breathing difficulties. Babies born by cesareans after labor has begun have less trouble breathing, and vaginally-born babies have the least difficulty breathing of all. The baby that has the most difficulty breathing on its own is the baby born by planned cesarean before 39 weeks.

Why is this? Labor contractions help squeeze the baby's chest and expel the fluid there. Hormones that are produced during labor help the baby's body be ready to breathe independently. In addition, the umbilical cord gets cut very quickly at a cesarean, cutting off a significant portion of the placental blood meant to perfuse the baby's lungs and help them get ready to start working.

Gestational age also influences a baby's readiness to breathe independently. Preemies have a much harder time initiating breathing and maintaining it without apnea or oxygen saturation issues. Until recently, gestational age was not thought to be that important once babies reached "term" (at least 37 weeks), but now we know differently.

For some time now, research has shown that babies born before 39 weeks have higher rates of Transient Tachypnea of the Newborn (TTN), Respiratory Distress Syndrome (RDS), and Persistent Pulmonary Hypertension (PPH). These babies then need to go to neonatal intensive care (NICU), experience many interventive procedures, and accrue significant costs. Some experience long-term effects.

Because of this, many hospitals have begun strongly encouraging doctors to schedule cesareans no earlier than 39 weeks, and ACOG (American College of Obstetricians and Gynecologists) has recommended that planned cesareans be delayed until at least 39 weeks. Unfortunately, not all doctors follow this recommendation, and many many cesareans are still being done at 38 weeks.

New Evidence for Waiting

A new study, recently published in the New England Journal of Medicine, once again highlights the importance of delaying planned cesareans until at least 39 weeks. Here are some excerpts from the press release:

NEW YORK – Babies do better after a scheduled Caesarean section if they're born no sooner than seven days before their due date, a new large study of U.S. births shows. Those delivered earlier had more complications, including breathing problems, even though they were full term, the researchers reported in [the] New England Journal of Medicine. Even just a few days made a difference, they said....

The study supports recommendations that elective C-sections be scheduled after 39 weeks unless tests show the infant's lungs are fully mature....

In the new study, the researchers, led by Dr. Alan Tita of the University of Alabama at Birmingham, examined a C-section registry from 19 academic medical centers to see how many of the surgeries were being done before the recommended 39 weeks and if the timing made a difference in the risk of complications.

They focused on 13,258 women who had a single child at a planned Caesarean and who had previously given birth the same way. Excluded were cases where medical issues warranted an early or immediate delivery. The infants were followed until they left the hospital or for four months.

More than a third of the C-sections were performed before 39 weeks, the researchers found. Those delivered at 37 weeks were twice as likely to have health problems, including breathing troubles, infections, low blood sugar or the need for intensive care. Fifteen percent of those born at 37 weeks and 11 percent born at 38 weeks had complications, compared to 8 percent of the babies delivered at 39 weeks.

Note that one-third of the planned c-sections in the study were done at 38 weeks, despite years of prior evidence that delaying till 39 weeks improves outcomes.

It is simply unconscionable that despite considerable, long-standing evidence to the contrary, one-third of contemporary elective cesareans were still carried out so early. When will doctors finally align their practice patterns with the evidence?

Some of the press releases also implied that it was mostly maternal request that was driving this trend towards 38-week cesareans, but in fact, the push for early cesareans is usually physician-driven. This is another recent trend in research and press releases: blame the mothers for problems instead of physician mismanagement.

One might also ask, why not delay a planned cesarean until at least 40 weeks? Even at 39 weeks, about 1 in 12 babies still had breathing difficulties. Although the difference did not reach statistical difference, the rate of complications was lower at 40 weeks than at 39.

There is no good reason for an arbitrary dictate to have planned cesarean done at 39 weeks, before a woman's due date. Unless there is a compelling medical reason, delay until the due date or until after spontaneous labor begins and outcomes will improve even more.

Second, I wish the medical journals would also press doctors to stop doing so many planned cesareans. The most optimal timing of cesareans is a red herring issue. Research is VERY clear that vaginally-born babies do better overall in so many ways, a point conveniently left out of the report.

The cesarean rate in the whole country is unconscionably high (over 30%), with cesarean rates in some hospitals exceeding 40 or even 50%. There is NO need for a cesarean rate this high. Most mothers and babies do better if they are given a chance at a vaginal birth.

A cesarean is an excellent thing for true emergencies, and there are also times when a planned cesarean is justified. But the overuse of cesareans today is putting a whole generation of babies, future babies, and mothers at risk unnecessarily.

Debating the timing of cesareans is not the real issue here; the overuse of unnecessary cesareans is.

Cesarean Timing and "Obesity"

Finally, timing of a planned cesarean may be particularly critical for women of size. Research shows that women of size tend to have longer menstrual cycles, which should delay their due dates, yet cycle length is rarely adjusted for by most doctors.

If a woman's cycle is 35 days, that means her "due date" by Last Menstrual Period (LMP) will be too early by a week. This is a critical point, especially when discussing planned cesareans.

Even if doctors follow the latest recommendations and schedule an "obese" woman's elective cesarean at 39 weeks, in reality this may well mean the baby is only 38 weeks, and subject to the higher risk of breathing issues noted above.

If the cesarean is scheduled at 38 weeks instead (as 1/3 of cesareans were in the report above), her baby will actually be born at 37 weeks, raising the risk for problems even more.

Of the women of size I know who have had elective cesareans, many of them had them at 38 weeks. This is putting these babies at risk unnecessarily; putting off the surgery just a little more really improves outcomes and helps babies in so many ways.

But even better in most cases would be to give those babies and mothers the benefits of labor.

*Image from Wikimedia Commons.