Effect of vaginal pH on efficacy of the controlled-release dinoprostone vaginal insert for cervical ripening/labor induction.

OBJECTIVE: To evaluate whether vaginal pH alters the efficacy of the controlled-release dinoprostone vaginal insert (Cervidil) for cervical ripening/labor induction. METHODS: Thirty-four women with an unfavorable cervix undergoing labor induction were enrolled in this prospective, double-blind investigation. Vaginal pH and Bishop score assessments were made by an independent examiner. All women received preinduction with the dinoprostone vaginal insert 10 mg intravaginally for 12 h. Twelve hours later, oxytocin induction initiated according to the standardized protocol and outcome data were collected. RESULTS: Mean (+/- SD) initial vaginal pH was 4.9 +/- 0.5 for the study cohort. No significant differences were noted between women with a high vaginal pH (> 4.5, n = 18) and those with a low vaginal pH (< or = 4.5, n = 16) with respect to maternal age, parity, gestational age, or initial Bishop score. Similarly, Bishop score change over the preinduction interval (3.2 vs. 3.3), time to active labor (28.6 vs. 24.6 h) and time to delivery (33.7 vs. 31.4 h) were not significantly different between the low and the high pH groups, respectively. Linear regression analysis revealed no significant association between vaginal pH and Bishop score change during the preinduction interval, time to active labor, time to complete dilatation, or time to delivery. CONCLUSION: Vaginal pH does not appear to influence the efficacy of the controlled-released dinoprostone vaginal insert for cervical ripening/labor induction.

Effect of vaginal pH on efficacy of misoprostol for cervical ripening and labor induction.

OBJECTIVE: We sought to evaluate whether vaginal pH has an effect on the relative efficacy of misoprostol for cervical ripening and labor induction. STUDY DESIGN: Thirty-seven gravid women with an unfavorable cervix and indication for labor induction were enrolled in this prospective, double-blind, observational study. Baseline assessments of cervicovaginal pH and Bishop score were made at the time of enrollment by an independent examiner. All patients received 50 microg misoprostol intravaginally every 6 hours for 12 hours. After the initial 12 hours of preinduction, a repeat Bishop score assessment was made by the same initial examiner. Patients not in active labor at 12 hours were placed on a standardized oxytocin induction regimen. Labor was managed by the on-call obstetric team, who remained blinded to pH assessment. Clinical outcomes were evaluated. Statistical analyses were made by the Student t test, the Fisher exact test, and linear regression analysis. RESULTS: Average initial vaginal pH was 4.8 +/- 0.5 (range, 3.5-7.0) for the study cohort. No significant differences were noted between those patients with low vaginal pH (< or =4.5) compared with those with high pH vaginal (>4.5) with respect to maternal age, parity, gestational age, or initial Bishop score. Similarly, Bishop score change over preinduction interval (5.6 vs 4.9), time to active labor (16.3 vs 17. 1 hours), time to complete dilatation (20.0 vs 19.9 hours), and time to delivery (21.0 vs 21.6 hours) were not significantly different between the low and high pH groups, respectively. Linear regression analysis revealed no significant association between vaginal pH and Bishop score change during preinduction interval, time to active labor, time to complete dilatation, or time to delivery. CONCLUSION: Vaginal pH does not appear to influence the efficacy of intravaginally administered misoprostol for cervical ripening and labor induction.

Misoprostol as a labor induction agent.

The objective of this investigation was to compare the efficacy, safety, and cost of intravaginal misoprostol as a labor induction agent to a standard protocol using prostaglandin E2 (Prepidil) and intravenous oxytocin. Thirty-eight patients requiring induction of labor with an unfavorable cervix (Bishop score < or = 5) were prospectively randomized to receive either 50 mcg misoprostol every 4 hours until delivery, or a single dose of PGE2 gel (0.5 mg) followed by intravenous oxytocin infusion. Changes in Bishop scores were recorded in a blinded fashion. Clinical outcomes were compared in the two groups, including induction-to-delivery times and cesarean section rates. Seventeen women were treated with misoprostol, 19 patients received PGE2/oxytocin, and two patients dropped out of the study. The groups did not differ significantly with respect to age, parity, gestational age, weight, height, reason for induction, or initial Bishop score. There was a significant difference in the median change of the Bishop score among those treated with misoprostol (4) and those of the control group (1) (P < 0.001). Fifteen (88%) receiving misoprostol delivered within 36 hours compared with 9 (47%) of controls (P = 0.01). Significantly more women in the misoprostol arm (8) experienced tachysystole when compared with the control group (0) (P < 0.01). There were no perinatal morbidities in either group. These data support misoprostol as an effective and economical cervical-ripening and labor-inducing agent.