Induction of labor in postterm pregnant women

Abstract

We have studied the outcome of labor induction in 145 postterm pregnant women in whom gestational age was properly assessed by ultrasound scanning. The induction techniques were adapted to the cervical states of the patients. Seventy-five patients (32 nulliparous and 43 multiparous) with favorable cervical states were successfully induced with intravenous oxytocin. In this group the frequency of Caesarean section was 2%. Seventy patients (45 mulliparous and 25 multiparous) with unripe cervices received 0.5 mg PGE 2 in viscous gel intracervically to prime the cervix and to induce labor; 38 (52%) were induced into labor after a single PGE 2-gel application whereas 26 (48%) needed labor augmentation with intravenous oxytocin after PGE 2-gel obtained cervical ripening. In 6 of the 20 patients the cervix did not ripen and the PGE 2-gel application had then to be repeated. The frequency of cesarean sections was 11%. In 5 out of the 145 patients (4%) the fetuses had signs of intrauterine growth retardation (IUGR) as assessed by ultrasound scanning, and postmaturity as verified by pediatric examination at delivery. All these fetuses belonged to nulliparous women with unripe cervices and all had to be delivered instrumentally (3 by cesarean section and 2 by ventouse) indicating the fragility of these children. If postterm pregnancy is complicated by an unfavorable cervical state intracervical application of PGE 2-gel seems to be an efficient method to prime the cervix and to induce labor. In most patients an uncomplicated vaginal delivery can be achieved by this procedure. However, nulliparous women with unfavorable cervices and signs of IUGR constitute a high risk group of patients at labor induction.