Prelabor rupture of membranes at term requiring labor induction - a feature of occult fetal cephalopelvic disproportion?

AIM: To examine the maternal and neonatal characteristics related to labor outcome following induction for prelabor rupture of membranes (PROM) after 37 weeks' gestation.

METHOD: All singleton pregnancies delivered following spontaneous or induced labor after 37 weeks in four years were analyzed. Patients with labor induction for PROM comprised the study group. Outcome of labor was analyzed according to gestational age at delivery.

RESULTS

Among the 13,505 patients in the entire cohort, 1710 (12.7%) had labor induction for PROM. These women were older and heavier, were more nulliparas and had more large-for-gestational age (LGA) infants, higher rates of instrumental and cesarean deliveries, and a shorter mean gestation, but no difference in height, mean birth weight, or incidence of male infants. Multiple logistic regression analysis confirmed that labor induction was a weak but significant independent factor for cesarean delivery (aOR 1.18, 95% CI: 1.01-1.38). The rates of cesarean delivery significantly correlated with gestational age at delivery for both LGA (P<0.001) and non-LGA (P<0.001) infants, together with significantly increased birth weight.

CONCLUSION

The results suggest that a likely explanation for the cesarean delivery following labor induction for PROM at term in our population is underlying cephalopelvic disproportion.