In-hospital maternal mortality in the United States: time trends and relation to method of delivery.

To study time trends in maternal mortality in the United States and to attempt to compare the risk of cesarean with vaginal delivery, information from the Professional Activities Study of the Commission on Professional and Hospital Activities for 3 years-1970, 1974, and 1978-was reviewed. For all deliveries, mortality per 100,000 deliveries declined from 25.7 in 1970 to 14.3 in 1978. For vaginal deliveries, mortality per 100,000 deliveries declined from 20.4 to 9.8. For cesarean deliveries, mortality per 100,000 births decreased more than for vaginal deliveries, from 113.8 to 40.9. Mortality for deliveries with no mention of complications, lacerations, or uterine rupture declined significantly from 1970 to 1978. Mortality for deliveries complicated by dystocia or malpresentation declined significantly from 1970 to 1974, but failed to decline thereafter. Mortality for deliveries complicated by a previous cesarean or by antepartum hemorrhage did not decline significantly from 1970 to 1978. For all complications with a sufficient number of vaginal and cesarean deliveries, except deliveries complicated by malpresentation or antepartum hemorrhage, mortality was at least twice as high in cesarean as in vaginal deliveries. Based on a comparison of mortality after a previous cesarean with mortality for all vaginal deliveries with no complication, the authors conclude that cesarean delivery is probably neither less than 2 nor more than 4 times more hazardous than vaginal delivery.