Third stage of labor: analysis of duration and clinical practice.

Abstract

Our purpose was to record gestational age-specific data for third-stage duration of labor, frequencies of retained placentas (undelivered at 30 minutes), manual removal of the placenta, and hemorrhage. Included were 45,852 singleton deliveries > or = 20 weeks' gestation from 1984 to 1992. Odds ratios, 95% confidence intervals, and actuarial life analysis with censoring of cases with manual placenta removal were performed. The frequency of retained placentas (2.0% overall) was markedly increased among gestations < or = 26 weeks (odds ratio 20.8, 95% confidence interval 17.1 to 25.4) and < 37 weeks (odds ratio 3.0, 95% confidence interval 2.6 to 3.5) compared with term. The frequency of manual removal (3.0% overall) was increased among gestations < or = 26 weeks (odds ratio 9.2, 95% confidence interval 7.5 to 11.4) and < 37 weeks (odds ratio 2.8, 95% confidence interval 2.4 to 3.1) compared with term. Hemorrhage (3.5% overall) was increased among subjects with manual placenta removal (odds ratio 10.4, 95% confidence interval 9.1 to 11.9); hemorrhage was also increased among gestations < or = 26 weeks (odds ratio 3.0, 95% confidence interval 2.3 to 4.0) and < 37 weeks (odds ratio 1.2, 95% confidence interval 1.01 to 1.3) compared with term. The frequency of hemorrhage peaked by 40 minutes regardless of gestational age. Life-table analysis predicted 90% of placentas would spontaneously deliver by 180 minutes for gestations at 20 weeks, 21 minutes at 30 weeks, and 14 minutes at 40 weeks; the predicted frequency of retained placentas was 42% higher than the recorded incidence. The duration of the third stage decreases and the frequencies of hemorrhage and manual removal decrease with increasing gestational age. Hemorrhage was associated with manual placental removal. Life-table analysis indicated that manual removal of placentas shortened the duration of the third stage of labor, especially among preterm deliveries. A prospective trial is needed to determine whether manual placental removal can reduce hemorrhage among prolonged third stages.