Compared with vaginal deliveries, nonemergency cesarean deliveries are associated with a reduced risk of neonatal complications in cases of breech (buttocks-first) presentation, according to a prospective study conducted in Latin America.¹ The odds of fetal death among cases of breech presentation are reduced by 70–80% with an elective or intrapartum cesarean birth compared with a vaginal birth. However, newborns with a cephalic (headfirst) presentation are more likely to have a prolonged stay in the intensive care unit or to die before hospital discharge if delivered by cesarean rather than vaginally, and women delivering this way are twice as likely to experience severe complications (including death) as women with vaginal deliveries.

Researchers analyzed data from the 2005 World Health Organization global survey on maternal and perinatal health, which was conducted at health care facilities in Argentina, Brazil, Cuba, Ecuador, Mexico, Nicaragua, Paraguay and Peru. Demographic, health and obstetric information was obtained from medical records for all women admitted for singleton deliveries at 123 health facilities during a 2–3 month period in 2004–2005. Cesarean deliveries were classified as elective if the decision to perform surgery was made before the start of labor, and as intrapartum if the decision was made during labor; emergency cesarean deliveries performed before the onset of labor were excluded. A total of 94,307 deliveries were included in the analyses, of which 66% were vaginal deliveries, 14% elective cesarean deliveries and 20% intrapartum cesarean deliveries. Multivariate analyses were used to determine the odds of various maternal and neonatal outcomes (e.g., maternal death, fetal death or neonatal mortality) according to the type of delivery; these analyses adjusted for institutional factors, maternal characteristics and (for neonatal outcomes) gestational age. Because breech deliveries pose greater risk than cephalic deliveries, the two types were analyzed separately.

Only 2% of women with vaginal deliveries experienced severe maternal complications (admission to the intensive care unit, blood transfusion, hysterectomy, a hospital stay longer than seven days or death), compared with 6% of women with elective cesarean deliveries and 4% of those with intrapartum cesarean births. In adjusted analyses, the odds of such complications among women with an elective or intrapartum cesarean delivery were twice those of women with a vaginal delivery (odds ratios, 2.3 and 2.0, respectively). In addition, women who had an elective or intrapartum cesarean delivery had substantially greater odds of receiving antibiotics after delivery, an indicator of infection (4.2 and 5.5). However, women delivering by elective or intrapartum cesarean were much less likely than women with vaginal deliveries to develop severe perineal lacerations, postpartum fistulas or both (0.1 and 0.1).

Fetal death occurred in 0.5% of pregnancies; in addition, about 1% of newborns died before hospital discharge, and 3% had intensive care unit stays lasting at least seven days. In cases of cephalic presentation, newborns delivered by elective or intrapartum cesarean were more likely than those delivered vaginally to have a prolonged intensive care unit stay (odds ratios, 2.1 and 1.9, respectively) and to die before hospital discharge (1.7 and 2.0). The odds of fetal death did not differ by delivery type.

In contrast, among cases of breech or other noncephalic presentation, elective and intrapartum cesarean deliveries were associated with a 70–80% reduction in the odds of fetal death compared with vaginal deliveries (odds ratios, 0.3 and 0.2, respectively). However, the odds of a prolonged intensive care unit stay or death before discharge did not differ among newborns delivered by elective or intrapartum cesarean and those delivered vaginally.

Because the poorer outcomes seen with cesarean deliveries (particularly intrapartum ones) might be due in part to medical problems that prompted the decision not to deliver vaginally, the researchers repeated the analyses for cephalic presentations, this time excluding cesarean deliveries that were performed because of fetal distress or other relevant conditions. In these analyses, newborns delivered by elective or intrapartum cesarean were still more likely than those delivered vaginally to have a prolonged intensive care unit stay (odds ratios, 2.1 and 1.8, respectively). The association between cesarean delivery and death before hospital discharge remained significant for elective procedures (1.8), but not for intrapartum ones.

Finally, to assess whether the lack of labor was contributing to the negative outcomes seen following elective cesarean delivery, the researchers stratified births according to whether labor occurred spontaneously. For cephalic presentations, the odds of a prolonged intensive care stay were higher among newborns delivered by elective cesarean following spontaneous labor than among newborns delivered vaginally following spontaneous labor (odds ratio, 1.4)—and higher still among newborns delivered by elective cesarean without spontaneous labor (2.2). The odds that a newborn would die before discharge were also elevated for elective cesarean births without spontaneous labor (1.8), but among women who did have spontaneous labor, the odds of neonatal mortality did not differ between elective caesarian deliveries and vaginal deliveries.

While acknowledging that the study's findings may not apply to settings with higher rates of perinatal death or lower rates of cesarean delivery, the researchers conclude that "any net benefit from the liberal use of cesarean delivery on maternal and neonatal outcomes, at the institutional or individual level, remains to be demonstrated, with the exception of fewer severe vaginal complications and better fetal outcomes among breech presentations." They recommend cesarean births for all breech presentations, as well as consideration of strategies that might convert breech presentations to cephalic ones. In addition, the researchers call for improved technologies for fetal monitoring during labor, which may help to reduce the use of cesarean delivery in cases of cephalic presentation.—S. London

REFERENCE

1. Villar J et al., Maternal and neonatal individual risks and benefits associated with cesarean delivery: multicentre prospective study, BMJ, 2007, 335(7628):1025.