Women choosing repeat cesarean deliveries and having
them at 37 or 38 weeks gestation, without a medical or obstetric
indication, are up to two times more likely to have a baby with serious
complications, including respiratory distress resulting in mechanical
ventilation and NICU admission.

UAB researchers, led by Alan T.N. Tita, M.D., Ph.D., assistant professor
in the UAB Department of Obstetrics and Gynecology Division of
Maternal-Fetal Medicine, and colleagues published their findings Jan. 8
in the New England Journal of Medicine.

"The cesarean rate in the United States has risen dramatically, from
20.7 percent in 1996 to 31.1 percent in 2006. A major reason is the
decline in attempted vaginal births after cesarean. Because elective
cesareans can be scheduled to accommodate patient and physician
convenience, there is a risk that they may be performed earlier than is
appropriate." Tita said. "We knew from previous small studies that
infants born before 39 weeks gestation are at increased risk for
respiratory distress. Because nearly 40 percent of the cesareans
performed in the United States each year are repeat procedures, we
undertook this large study to describe the timing of elective repeat
cesareans and assess its relationship with the risk of various adverse
neonatal outcomes."

Tita and colleagues looked at women who had elective repeat cesarean
sections at the 19 centers of the Eunice Kennedy Shriver National
Institute of Child Health and Human Development (NICHD) Maternal-Fetal
Medicine Units Network from 1999 through 2002. They were selected from
the network's Cesarean Section Registry. The registry contains detailed,
prospectively-collected information on nearly 50,000 women with a prior
cesarean who underwent either repeat cesarean delivery or a trial of
labor at the 19 centers over the 4-year period. Of the 50,000, 13,258
women underwent an elective cesarean of a viable infant at 37 weeks
gestation or later, in the absence of labor or other obstetric or
medical indications for early cesarean delivery (prior to 39 weeks).

The researchers looked at whether an infant who was delivered at 37
weeks later died or was diagnosed with a number of conditions, including
respiratory distress syndrome and/or transient tachypnea of the newborn,
newborn sepsis, seizures, necrotizing entercolitis, hypoxic ischemic
encephalopathy, required ventilator support within 24 hours of birth,
had umbilical cord arterial pH (a measure of oxygenation) below 7.0, an
Apgar score at five minutes of three or below, was admitted to a
neonatal intensive care unit or required prolonged hospitalization.

Of the 13,258 women who had elective repeat cesarean sections, as many
as 35.8 percent were delivered before 39 weeks. Babies born at 37 weeks
were two times more likely to suffer with conditions common to babies
born too soon, and at 38 weeks, they were one and a half times more
likely.

Tita said these findings, along with other studies, underscore the
importance of not delivering a baby before 39 weeks for the sake of
convenience. "Unfortunately, these early deliveries are associated with
a preventable increase in neonatal morbidity and NICU admissions, which
carry a high personal and economic cost. These findings support
recommendations to delay elective delivery until 39 weeks gestation and
should be helpful in counseling women on the necessity of waiting to
deliver."

UAB is one of the original eight National Institute of Child Health and
Human Development (NICHD) research sites commissioned in 1986 and is the
only facility in the country that is involved in all three of the NIH
research initiatives for maternal, child and family health, the Neonatal
Research Network, Maternal-Fetal Medicine Units Network and the Global
Network for Women and Children Research. The under-construction,
400,000-square-foot UAB Women and Infants Center, scheduled to open in
2010, will provide medical evaluation and private inpatient rooms for
expectant mothers experiencing both normal pregnancies and severe
pregnancy-related complications, for both healthy and critically ill
newborns and for women undergoing gynecological procedures or treatment
for gynecologic cancers.

To view an interview with Dr. Tita visit www.uab.edu/news.