PREGNANCY & CHILDBIRTH | Elective C-Sections Before 39 Weeks Associated With Increased Risks to Infants, Study Says
[Jan. 8, 2009]

About one-third of elective caesarean section deliveries are performed before 39 weeks' gestation, which increases risks to infants, according to a study published in the New England Journal of Medicine, the Wall Street Journal reports. The study analyzed 13,258 elective c-sections -- defined as "a delivery performed in the absence of labor or other recognized medical or obstetrical indications for delivery" -- that took place in the U.S. between 1999 and 2002. Thirty-six percent of the deliveries were performed at 37 or 38 weeks' gestation, and the others were performed after 38 weeks (Winstein, Wall Street Journal, 1/8). All of the deliveries in the study were performed at one of 19 U.S. academic medical centers that are part of the Eunice Kennedy Shriver National Institute of Child Health and Human Development's Maternal-Fetal Medicine Units Network (Gordon, HealthDay/U.S. News and World Report, 1/7).

According to the Journal, 37 weeks is considered the time when a fetus is full term, but most medical experts have long recommended waiting until 39 weeks to perform an elective c-section. Elective c-sections currently represent about one in 14 U.S. births, the Journal reports (Wall Street Journal, 1/8). The American College of Obstetricians and Gynecologists recommends that elective c-sections should occur at 39 weeks or later if no medical concerns are present for the woman or infant (HealthDay/U.S. News and World Report, 1/7).

According to the study, infants delivered the earliest had higher rates of complications, with 5.5% of infants delivered at 38 weeks and 8.2% of those delivered at 37 weeks displaying various respiratory problems. Only 3.4% of infants delivered at 39 weeks showed signs of such complications. The study found that other complications for infants delivered by early c-sections included infections, five days or more of hospitalization and a need for cardiac resuscitation. Women who went into labor or experienced medical emergencies that led to c-section deliveries were not included in the study, which examined only repeat pregnancies because a woman's first c-section "usually isn't elective," the Journal reports. The study also found that women electing to have c-sections were more likely to be white, married, have private insurance and have had prenatal care that included ultrasounds (Wall Street Journal, 1/8). Deliveries performed one, two or three days before 39 weeks had a 21% increased risk of complications to the infant, the study showed (Kaplan, Los Angeles Times, 1/8). According to the study, about 50% of repeat c-sections are considered to be elective, the equivalent of about 300,000 such deliveries out of the 4.3 million total births and 1.3 million c-sections -- including first-time procedures -- performed in the U.S. annually. In an editorial that accompanied the study, Michael Greene, the director of obstetrics at Massachusetts General Hospital, recommended that elective c-sections not be performed before 39 weeks in most cases.

The researchers said that the main reason women elect to have an early c-section is to ensure that her regular physician is available. Greene said that patients and obstetricians "know that this is driven by the patient wanting 'her doctor' to do the delivery, and the doctor wants to maintain that patient relationship and wants to do it if possible." He added that the study shows the need for "a frank conversation between doctor and patient about what the risks and tradeoffs are about delivering at 37, 38, 39 (weeks), in terms of both risk to the newborn and risk to the fetus in utero."


Alan Tita, the study's lead researcher and an obstetrician at the University of Alabama, said that women "usually would like to be delivered as soon as they hit" 37 weeks and that physicians "would like to accommodate them." However, "given the available information, we would recommend that women who plan to have an elective caesarian wait until the 39th week, at least," he said (Wall Street Journal, 1/8). Peter Bernstein, a maternal-fetal medicine specialist at Montefiore Medical Center and Albert Einstein College of Medicine in New York City, said, "In the academic world, these [hospitals] are among the top institutions, and that more than one-third apparently aren't following ACOG guidelines is a surprise" (HealthDay/U.S. News and World Report, 1/7).

John Thorp, professor of obstetrics and gynecology at the University of North Carolina-Chapel Hill, said that there are differences between infants delivered at 37 weeks vaginally and those delivered via elective c-section. He said, "We would not worry about a 37-and-a-half week baby born vaginally with the onset of labor" because in that situation, "there is some signal from a baby to his mother that says 'I'm ready'" (Rubin, USA Today, 1/8). Catherine Spong of the National Institute of Child Health and Human Development -- which sponsored the study -- said, "I think that as a patient of a physician, you might be convinced that being close to 39 weeks is probably good enough." She added, "Before this, we didn't have the data to say that there would be more risk." According to the Washington Post, most infants with the complications listed in the study can recover quickly, but in some cases more serious complications can arise that require testing, treatment in intensive care units and hospitalization for several days (Stein, Washington Post, 1/8).

'Controversial' C-Section Rates

The Journal reports that c-sections have "for years been controversial, and health officials have repeatedly sought to reduce their frequency to minimize post-partum complications and reduce costs." Nonetheless, 31% of U.S. deliveries were through c-sections in 2006, compared with 20% of deliveries in 1996 and 5% in 1970, according to Centers for Disease Control and Prevention data. The World Health Organization recommends that nations' c-section rates should be no more than 15% (Wall Street Journal, 1/8). According to the Post, the reasons for the increase in c-sections in the U.S. have been the "subject of intense debate." Factors that contribute to the increase include women having children later in life, when complications are more likely; doctors identifying more problems early in pregnancy and intervening to protect the woman or the infant; and the fact that once a woman has had a c-section, she is much less likely to have a vaginal birth (Washington Post, 1/8).