Cesareans Significantly Increase Mothers' Mortality Risk

PARIS, Aug. 31 -- Women who opt for an elective cesarean have a threefold higher risk of mortality than those who choose vaginal delivery, according to investigators here.

Women who died during or within 42 days of giving birth were significantly more likely to have had a cesarean than women who survived childbirth (41.5% versus 14.9%), reported Catherine Deneux-Tharaux, M.D., M.P.H., of Hopital Teno, and colleagues, in the September issue of Obstetrics & Gynecology.

Both cesarean deliveries initiated before onset of labor and those initiated during labor significantly increased risk of maternal death. Intrapartum cesarean was associated with a small, statistically insignificant increase in risk over prepartum cesarean (adjusted odds ratio 1.39, 95% CI 0.62 to 3.15).

"Although cesarean delivery is increasingly perceived as a low-risk procedure, it is still associated with an increased risk of postpartum maternal death compared with vaginal delivery, even when performed before labor," said Dr. Deneux-Tharaux and colleagues.

The rates of postpartum maternal death are relatively low in France as in other developed countries -- one in 10,000 live births for France compared with a one in 3,500 chance of pregnancy-related death in the United States -- but have shown little improvement over the past 20 years.

The increased maternal mortality was caused primarily by venous thrombosis (25.9%), infection (14.8%), and anesthesia complications (14.8%), they found. Postpartum hemorrhage was no higher for cesarean deliveries. None of these complications was among the most frequent causes of death after vaginal births (7.9%, 2.6% and 2.6% respectively).

Postpartum hemorrhage was actually a less common cause of death following cesarean delivery than after vaginal birth (22.2% versus 50.0%).

"This may be considered surprising, because mean blood loss associated with cesarean delivery has been shown to be greater than after vaginal delivery," the investigators wrote, but may be due to increased surveillance and care for women after a cesarean.

Cesareans were associated with a significantly increased risk of postpartum maternal death compared with vaginal delivery even after adjusting for age, nationality, parity, and premature birth (odds ratio of 3.64; 95% confidence interval 2.15 to 6.19). The odds decreased only slightly to 3.3 after excluding preterm births.

The study examined postpartum maternal mortality using a national surveillance program in France called the Confidential Enquiry on Maternal Deaths that included 269 deaths during the five-year study period from 1996 to 2000.

The researchers narrowed their analysis to 65 maternal deaths that did not occur before delivery or after hospitalization or chronic illness during pregnancy or result in multiple births. A control group consisted of 13,478 live, term births in France recorded in the 1998 French National Perinatal Study.

"The method of delivery may constitute one potentially modifiable risk factor of maternal mortality," the investigators wrote, that "needs to be taken into account by clinicians and women when balancing the risks against the benefits of the different methods of delivery."