After First Cesarean, Risks Increase in Next Pregnancy
Reuters Health Information 2007. © 2007 Reuters Ltd.
By Will Boggs, MD

NEW YORK (Reuters Health) Feb 16 - Adverse outcomes in the next birth are more common among women who deliver their first child by cesarean section than those who deliver their first child vaginally, according to a report in the February issue of Obstetrics & Gynecology.

"Women who request elective caesarean section for no medical indication should be aware of these potential increased risks for themselves and their babies in their next and future births," Robyn Kennare, a midwife with the Department of Health, Adelaide, South Australia, told Reuters Health.

Kennare and colleagues estimated the association between cesarean delivery of a first pregnancy and adverse obstetric or perinatal outcomes in the second birth. For this retrospective study, the investigators used outcome data collected between 1998 and 2003 for the second pregnancies of 8725 women who previously underwent cesarean section and 27,313 women who previously delivered vaginally.

The risks for placenta previa, antepartum hemorrhage, malpresentation, prolonged labor, elective and emergency cesarean delivery, uterine rupture, placenta accreta and emergency or elective cesarean were significantly higher among women who delivered by cesarean section in their first pregnancy than among women who first delivered vaginally, the authors report.

Infants in the cesarean group were also more likely to be preterm (before 37 weeks' gestation) or very preterm (before 32 weeks' gestation), small for gestational age, low birth weight or stillborn, compared with infants in the vaginal group, the researchers note.

However, previous cesarean delivery was not associated with increased risk of neonatal death, the report indicates.

"Although the absolute risks of many of the outcomes are not high, some of the outcomes are very serious ones or may have very serious consequences, e.g., stillbirth, uterine rupture, and placenta accreta," Kennare said.

"Our data system is currently being updated to enable linkage of births to women longitudinally," Kennare said. "Further studies, in which the indication for the first caesarean section and all details of the first birth are known, are required to determine if these increased risks are real."

Obstet Gynecol 2007;109:270-276.