[Effect of induction delivery on maternal-neonatal outcomes in 41 gestational weeks primiparae]

To estimate the maternal-neonatal morbidity associated with induction deliveries compared with spontaneous deliveries in 41 gestational weeks uncomplicated primiparae.

Three hundred and seventy-four uncomplicated primiparous deliveries at 41 gestational weeks at Peking Union Medical College Hospital from Sept 2002 to Apr 2007 were reviewed, including 225 women undergoing induced labor and 149 women undergoing spontaneous labor. The induction methods included drug induction (173), rupture of membrane induction (5) and combined drug with rupture of membrane induction (47). The maternal morbidity, delivery method, maternal cost on hospital stay and neonatal asphyxia associated with induction deliveries or spontaneous deliveries were retrospectively analyzed.

(1) There was no maternal death. The caesarean section rate in the induction group (44.0%, 99/225) was significantly higher than that of spontaneous group (18.1%, 27/149; P<0.05). (2) No statistically significant difference (P>0.05) was observed between induction group and spontaneous group in the following puerperal complications: postpartum hemorrhage (2.7%, 6/225 and 1.3%, 2/149 respectively), puerperal morbidity (0.9%, 2/225 and 0.7%, 1/149 respectively), severe amniotic fluid contamination (11.6%, 26/225 and 13.4%, 20/149 respectively), wound infection (0.9%, 2/225 and 0.7%, 1/149 respectively) ,urinary retention(4.4%, 10/225 and 3.4%, 5/149 respectively), traumata (0.4%, 1/225 and 0 respectively) and neonatal asphyxia (1.3%, 3/225 and 2.0%, 3/149 respectively). (3) The average duration of first stage of labor in the induction group (413 min) was not significantly different from that of spontaneous group (461 min; P>0.05). In the induction group, more women had precipitate labors (P<0.05) and the average duration of the second stage of labor was shorter than that of spontaneous group (40 min and 48 min, P<0.05). (4) Spontaneous group had shorter maternal hospital stay [(5.7 +/- 1.9) days vs (6.9 +/- 2.7) days, P<0.05] and caesarean section after induction had the highest hospital expense (P<0.05).

Induction delivery at 41 weeks of gestation increases the rates of caesarean section, precipitate labor, clinical workload and hospital costs. Induction delivery as a prevention method of over due labor needs to be further discussed. Uncomplicated pregnancies of 41 weeks should be intentionally monitored if continued surveillance is possible. They should wait for spontanous delivery, and decision of induction should be made based on its benefit to the case.