Ripening of the uterine cervix and induction of labour at term with prostaglandin E2 in viscous gel. [Multicenter experiences with the intracervical administration of a new PGE2 gel in labor induction]. A randomized trial comparing vaginal and cervical prostaglandin gel for cervical ripening and labor induction. [Comparison between prostaglandin E2 gel and oxytocin in medically indicated labor induction]. Prostaglandin E2 cervical ripening without subsequent induction of labor. Premature rupture of membranes near term: induction of labor with endocervical prostaglandin E2 gel or intravenous oxytocin. Prostaglandin E2 gel for cervical ripening in patients with an indication for delivery. Sequential outpatient application of intravaginal prostaglandin E2 gel in the management of postdates pregnancies. Vaginal administration of PGE2 for induction of labor stimulates endogenous PGF2 alpha production.
In order to achieve ripening of the uterine cervix or induce labour in patients at term with an unfavourable cervical state, 1 mg of prostaglandin E2 (PGE2), suspended in a viscous gel, was instilled into the cervical canal. In a pilot study, 41 patients received the PGE2-gel. Twenty-three of these, (56%), went into labour, and delivery occurred without further stimulation within 15 hours. In the remaining 18 patients, there was a marked improvement of the cervical state, which changed from an average (modified) Bishop score of 2.5 to 6.1 within 24 hours. In a double-blind study comprising 20 nulliparae, 10 received gel containing PGE2 and 10 gel without prostaglandin. Cervical state did not change significantly (Bishop score 3.6 and 4.0) after 24 hours in patients receiving placebo gel. In those receiving PGE2 gel, 8 went into labour and were delivered without further induction within 13 hours. Two patients showed an increase in Bishop score from 3 to 6 and 7, respectively, after 24 hours. They were then induced by oxytocin and delivery occurred after 8 and 10 hours. The results suggest that administration of PGE2 intracervically can induce ripening of the cervix in patients at term with an unfavourable cervical state, and thus facilitate delivery. With the participation of four Swiss obstetric clinics, medically indicated inductions of birth (with living fetuses) were performed using a new, stable PGE2 gel, and documented according to a uniform protocol. The study was conducted to investigate the efficacy of 0.5 mg of PGE2, in 2.5 ml of a vehicle (Triacetin) not yet commercially available, for local cervical maturation (n = 41). Thirty-nine patients selected by prospective randomization, in whom birth was induced conventionally, served as a control group. The efficiency of the prostaglandin gel alone or respectively with additional administration of oxytocin was evaluated on the basis of the clear changes in the cervical findings observed within 12 or respectively 24 hours, the spontaneous births, or, in the case of cesarean deliveries, according to the pelvic score. Application of PGE2 alone led to impressive changes of the cervix score and, in 34 of the 41 cases, to regular contractions after an average time of 87 minutes. After 12 hours, prior to administration of oxytocin, 43% of the patients were already delivered. The combination of locally applied PGE2 gel with conventional oxytocin induction significantly increases the number of successful inductions. The percentage of unsuccessfully attempted inductions was reduced to 24% in the PGE2 gel group as compared to 44% in the control group. To compare the effectiveness of intravaginal and intracervical prostaglandin E2 (PGE2) gel for cervical ripening, defined as an increase of 3 or greater in the Bishop score, and for induction of labor.
                Women with Bishop score 4 or less were assigned randomly to receive either 2 mg PGE2 intravaginally (n = 125) or 0.5 mg intracervically (n = 122). If the Bishop score was 4 or less, another dose of PGE2 was given after 6 hours, and up to two additional doses were given 6 hours apart on the second day. An oxytocin infusion was begun when the Bishop score was 5 or greater in absence of spontaneous labor, or if labor had not begun on the third day.
                Baseline characteristics of the two groups were similar. Survival analysis showed that time from PGE2 application, to obtain an increase of 3 or greater in the Bishop score, to vaginal delivery was significantly shorter with intravaginal PGE2 (logrank test: P = .003 and < .001 after stratification for parity, respectively). Thirty-one percent of women in the intravaginal gel group required oxytocin for labor induction compared with 63% in the intracervical group (P < .001). There were no significant differences in relation to cesarean delivery rate, Apgar scores at 5 minutes, and arterial umbilical cord pH, although the power of our study was limited to detect differences in proportions of adverse outcomes.
                Vaginal PGE2 gel is more effective than intracervical gel for cervical ripening and labor induction. The use of prostaglandins (PG) increasingly replaces the "classical" method of induction of labour by means of oxytocin and amniotomy, the last-named method being associated, especially in women with an unripe cervix, with side effects like prolonged labour and a higher rate of obstetric surgery. In this study the point of interest was whether prostaglandins offer any advantages over the classical method in respect of efficacy and maternal and foetal tolerance. 99 patients subdivided into primiparae and multiparae were randomly assigned to group A or B. In group A labour was induced with 1 mg resp. 2 mg PGE2 intravaginally at an interval of 6 hours. In group B the method of induction consisted of intravenous oxytocin and amniotomy. The success rate of induction was almost equal in both groups. However, in those patients where PGE2 induction did not succeed and who could not be delivered within 12 hours the cervical score was significantly improved in comparison to the oxytocin group. Based on the experience reported in the literature, one might speculate that an increased dosage could still improve the results of vaginally administered PGE2 gel. To determine whether outpatient administration of intracervical prostaglandin (PG) E2 gel decreases the interval to delivery and duration of labor.
                A randomized, double-blind, placebo-controlled trial compared the intracervical placement of 0.5 mg PGE2 gel with placebo in 61 pregnant women at 38 weeks' or greater gestation with Bishop scores less than 9. Transvaginal cervical length, fetal fibronectin, and Bishop score were assessed before gel placement. Subjects were then allowed to go into spontaneous labor unless an indication for induction developed.
                Thirty women were assigned to PGE2 and 31 to placebo. There were no significant demographic differences between the groups and there were no differences in cervical length, fetal fibronectin status, or Bishop scores. Fifteen women in the PGE2 group and five in the placebo group went into labor and delivered within the first 2 days after gel placement (P = .007). The median interval to delivery was significantly shorter in the PGE2 group, at 2.5 days, compared with placebo, at 7 days (P = .02). Nulliparas in the PGE2 group had a median interval to delivery of 2 days, compared with 7 days for nulliparas receiving placebo (P = .03). Active phases of labor were significantly shorter in the PGE2 group and for women with a negative fetal fibronectin test who received PGE2.
                Outpatient administration of intracervical PGE2 gel shortened intervals to delivery and shortened labor. We have studied the influence of endocervical application of 0.4 mg prostaglandin E2 (PGE2) in gel on the clinical outcome of pregnancies of at least 36 weeks' duration complicated with premature rupture of the membranes (PROM) and unripe cervix, (modified Bishop score of 7 or less). There were 579 women in the study. The PGE2 gel was applied within the first 12 hours after PROM. The first 60 women were randomly divided into controls given oxytocin infusions and experimental subjects given PGE2 gel. All others were given PGE2 gel, and the results were compared with those obtained in patients with similar criteria who were treated with oxytocin infusions during the preceding year. The clinical outcome was significantly better in the PGE2-treated patients than oxytocin-infused patients. PROM to delivery interval and the incidence of operative deliveries were significantly reduced. No adverse effects on the neonates were observed and the incidence of neonatal infection declined. It is concluded that cervical ripening with PGE2 gel in patients with PROM and unripe cervix near term significantly improves the outcome for both mother and child. To determine if labor can be induced safely and efficiently in patients with a medical or obstetric indication for delivery before 41 completed weeks of gestation by pre-induction cervical ripening with prostaglandin (PG) E2 gel.
                One hundred eighteen women with confirmed indication for induction of labor before 41 completed weeks were randomized in a double-blind fashion to either intracervical PGE2 gel or placebo before induction by a standard oxytocin protocol. Data regarding the change in Bishop score, interval to complete dilation, maximal oxytocin dose required to establish labor, and route of delivery were collected. Apgar scores and umbilical artery pH were also recorded.
                The maximum oxytocin dose required to establish progressive labor was significantly lower in the PGE2 group (10.06 +/- 8.50 versus 13.35 +/- 9.27 mU/minute, P = .014). The cesarean rate was also significantly lower in the PGE2 group (13.1 versus 31.6%, P = .016).
                Pre-induction intracervical deposition of 1 mg PGE2 gel decreased the amount of oxytocin required to induce progressive labor and decreased the cesarean rate in patients who had medical or obstetric indications for delivery before 41 completed weeks. This was accomplished without negative effect on Apgar score or umbilical artery pH. A randomized blinded investigation was undertaken to determine the efficacy and safety of sequentially applied intravaginal prostaglandin E2 (PGE2) gel for accelerating cervical ripening in an outpatient setting in low-risk prolonged pregnancies. Fifty women with uncomplicated pregnancies at or beyond 41 weeks' gestation and Bishop scores below 9 received twice-weekly outpatient administration of gel containing 2.0 mg of PGE2 or placebo. Thirty nulliparas and 20 multiparas were enrolled. The PGE2 gel failed to improve cervical ripening over placebo, as judged by Bishop scores. There was no difference between the groups in gestational age on admission to the labor and delivery suite, number of gel applications, requirement for oxytocin, incidence of cesarean delivery, or neonatal outcome. Only two patients (4%) experienced regular uterine contractions after gel insertion; these subsided spontaneously in both. None of the subjects experienced labor, tetanic contractions, evidence of fetal distress, or any other side effects related to gel insertion. We conclude that PGE2 gel in this dosage may be used safely in an outpatient setting, but more frequent application or earlier initiation may be required to produce a clinical effect. Prostaglandin E2 is effective for induction of labor but many preparations exist using a variety of vehicles from which the active ingredient may not be equally available. Plasma concentrations of bicyclic PGE2 metabolite (PGEM) and 13, 14-dihydro, 15-keto PGF2 alpha (PGFM) were measured following administration of a 3mg PGE2 vaginal tablet or 1mg PGE2 vaginal gel to twenty-four parous women with favorable induction features, randomly allocated to receive one or other preparation. PGEM increased rapidly following both administration of the 3mg PGE2 vaginal tablet and the 1mg PGE2 vaginal gel, reaching a peak within 40 minutes of PGE2 administration. The maximal rise in PGEM in the gel group correlated directly with the change in cervical score and inversely with the need for augmentation with oxytocin and the induction-delivery interval. A secondary rise in PGFM was noted in both groups 3-4 hours following PGE2 administration. The magnitude of the increase in PGE2 may be important in the clinical response to PGE2 administration, while PGE2 absorption may switch-on endogenous PGF2 alpha production, similar to what is seen in spontaneous labor.
PGE2 increases successful vaginal delivery rates in 24 hours and cervical favourability with no increase in operative delivery rates. Sustained release vaginal PGE2 is superior to vaginal PGE2 gel with respect to some outcomes studied.
Further research is needed to assess the best vehicle for delivering vaginal prostaglandins and this should, where possible, include some examination of the cost-analysis.
[Note: The 10 citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]