Studies of Vaginal, Cesarean Deliveries Are a Wash : Trials often reach opposing results and have failed to compare elective C-section vs. planned vaginal birth.


PRAGUE — Neither elective cesarean section nor planned vaginal birth has yet been convincingly shown to provide the lower rate of perinatal and maternal complications in studies.

Most trials have not been randomized, have often reached opposing results, and have not compared elective C-section against planned vaginal birth, stymieing clinicians' ability to conclude which may offer the least amount of risk to the newborn and mother, Dr. Ola Didrik Saugstad said at the 20th European Congress of Perinatal Medicine.

Retrospective comparisons of elective repeat C-sections and trial of labor (prior to a repeat C-section) in term infants have alternately suggested that elective repeat C-section may increase an infant's risk of respiratory problems, hyperbilirubinemia, and a longer length of stay in the hospital (Pediatrics 1997;100:348–53), yet also confer a reduced risk of sepsis and an Apgar score of less than 6 at 1 minute.

Another study found no difference between the two delivery strategies in overall perinatal or maternal morbidity or mortality (N. Engl. J. Med. 1996;335:689–95), said Dr. Saugstad of the department of pediatric research at the Rikshospitalet University Hospital, Oslo.

Dr. Saugstad and his colleagues have conducted a prospective study comparing 17,828 planned vaginal deliveries and 825 elective C-sections that occurred during January through June 1999 in Norway. There was no difference between the two groups in neonatal mortality or the percentage of infants with an Apgar score of less than 7 at 1 minute or less than 4 at 5 minutes. But significantly more infants who were delivered with a planned C-section were transferred to the neonatal ICU (18%) than were babies born with a planned vaginal delivery (9%). Babies delivered by a planned C-section also had significantly higher rates of pulmonary disorders, hypoglycemia, and anemia. Vaginally born infants were delivered at an older mean gestational age than C-section infants (39.4 weeks vs. 38.4 weeks) in the study, which is in press for the American Journal of Obstetrics and Gynecology.

In studies involving small or extremely- low-birth-weight infants, comparisons of elective versus selective C-section, C-section with labor versus C-section without labor, and vaginal delivery versus C-section have generally shown no significant differences in perinatal or maternal outcomes. But these studies have mostly been retrospective and have often compared infants of dissimilar gestational age and birth weight, Dr. Saugstad said.

A Cochrane review of six studies involving 122 women found no significant differences between elective and selective C-section on perinatal and maternal outcomes, citing that there was not enough evidence to evaluate the policy of elective C-section for small babies (Cochrane Database Syst. Rev. 2001;2:CD000078).

In a retrospective cohort study, C-section with labor was associated with significantly higher rates of grade 3 or 4 intraventricular hemorrhage, periventricular leukomalacia, and neurodevelopmental impairment at 18–22 months of age. But newborns who were delivered by C-section without labor had a significantly older gestational age than those who were delivered by C-section with labor. Correction for this and other risk factors made the difference in complications nonsignificant (Am. J. Obstet. Gynecol. 2003;189:501–6).

In a smaller retrospective study of extremely-low-birth-weight infants with a gestational age of less than 26 weeks at birth, significantly more neonates born vaginally survived than (21 of 27) than did those born by C-section (9 of 21).

Vaginally born infants tended to have lower rates of mechanical intervention, surfactant treatment, grade 3 or 4 intraventricular hemorrhage, necrotizing enterocolitis, or sepsis. But infants who were delivered by C-section had significantly lower birth weight, umbilical artery pH, and rectal temperature than vaginally delivered babies (Am. J. Perinatol. 2003;20:181–8).

Results from the multicenter, randomized Term Breech Trial showed that vaginally born infants had significantly greater mortality (5%) at up to 6 weeks of follow-up than those delivered by C-section (1.6%) (Lancet 2000;356:1375–83). But there was no difference in either maternal (Am. J. Obstet. Gynecol. 2004;191:917–27) or neonatal outcomes (Am. J. Obstet. Gynecol. 2004;191:864–71) after 2 years of follow-up, Dr. Saugstad said.

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