Active management of prolonged pregnancy

We assessed perinatal morbidity and mortality of prolonged pregnancies (> or = 294 days) compared with those of term gestations. We also evaluated the impact of induction of labor compared with spontaneous onset of labor.

This observational study included consecutive cases treated at Chicago Lying-In Hospital from July 1980 to December 1984. Complications, presence of meconium, indications for cesarean section, mode of delivery, perinatal morbidity (and mortality), meconium aspiration, and duration of labor were compared with those in the total hospital population, in infants weighing > or = 2500 gm, and within prolonged gestation groups; spontaneous onset and induced ("active management") labors were also compared. The chi 2 analysis was used.

Of 12,930 deliveries there were 707 prolonged gestations (5.5%) and 10,698 with infants > or = 2500 gm. Among the prolonged gestations 67% were in multiparous women and 33% in primiparous women. Labor started spontaneously in 62%, and 38% underwent induction; the overall cesarean section rate was 17% with similar indications in both spontaneous onset and induction groups. Meconium was present in 34%; it was present in 23% of inductions, which is fewer (p < 0.01) than among those with spontaneous onset of labor (40%). Also there were fewer depressed neonates at 5 minutes (p = 0.03) among inductions. Meconium aspiration was seen in 24, with nine deaths. The perinatal mortality was 14 per 1000 (corrected 12.7/1000), significantly more than in the general population. Among those with spontaneous onset of labor it was 20.5 per 1000; there were no deaths among inductions. Postpartum maternal morbidity was 16% among cesarean sections and 4% among vaginal deliveries.

Prolonged gestation has a high perinatal morbidity and mortality rate. All perinatal deaths were observed among patients whose labor started spontaneously. "Active management" (induction at 42 weeks) did increase the primary cesarean section rate compared with that of the general obstetric population; it did not do so among prolonged gestations and prevented perinatal deaths in this group. From this experience an active approach seems justified.