[Artificial induction of labor at term for medical reasons. Comparison of 2 technics for labor induction, oxytocin + early artificial rupture of the membranes versus prostaglandin E2 vaginal gel. Open randomized controlled study]. [Comparison between prostaglandin E2 gel and oxytocin in medically indicated labor induction]. [Multicenter experiences with the intracervical administration of a new PGE2 gel in labor induction]. [Induction of labor. Prostaglandin E2 vaginal tablets compared with intravenous oxytocin for induction of labor in premature rupture of the membranes and immature cervix]. Does prostaglandin confer significant advantage over oxytocin infusion for nulliparas with pre-labor rupture of membranes at term? Labor characteristics of uncomplicated prolonged pregnancies after induction with intracervical prostaglandin E2 gel versus intravenous oxytocin. Prostaglandin E2 for induction of labor in patients with premature rupture of membranes at term. Prostaglandin E2 gel for cervical ripening in patients with an indication for delivery. Prostaglandin E2 gel compared to oxytocin for medically-indicated labour induction at term: a controlled clinical trial.
Labor induction for medical reasons is a situation rather well-controlled by the combination: "oxytocin-amniotomy" when the cervix is favorably open. However, new induction techniques are currently under study, especially vaginal administration of PGE2 which presents the advantage of being simple to administer and better accepted by the patients. This study compared the classical technique, oxytocin perfusion and early artificial rupture of the membranes, with the vaginal administration of PGE2 gel (first dose: 1 mg, second dose 1 or 2 mg, six hours later). The success rate of both techniques is comparable, approximately 70 p. cent. Also, the times between amniotomy and delivery are identical, approximately 5 hours. On the contrary, the lapses of time between the onset of the induction and the delivery, vary significantly, being always longer in the PGE2 group. However, the dose of vaginal PGE2 gel as well as the time of artificial membrane rupture could be modified in order to decrease the delay of the effect. 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. 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. In a material of 88 patients with premature rupture of the membranes and unripe cervix, a comparative investigation was undertaken to compare the effects of prostaglandin E2 (PGE2) vaginal tablets and intravenous oxytocin on induction of labour. The patients were subdivided at random into two groups: 42 patients treatment with PGE2 and 46 treatment with intravenous oxytocin. The results did not reveal any significant differences in the numbers of successful inductions regardless of the Bishop score at the commencement of stimulation but the duration of induction was found to be briefer in the oxytocin group. No significant differences were observed in the numbers of instrumental interventions in the two groups nor in the frequencies of side effects and in the employment of analgesics. Treatment with PGE2 vaginal tablets is considered to be more acceptable by the patients and easier for the staff to use. The tablets were just as safe and reliable in use as intravenous oxytocin for induction of labour in cases of premature rupture of the membranes and Bishop scores less than 6, but the duration of induction was significantly longer. Ninety-four nulliparous women with a poor cervical score (less than 6) who had premature rupture of membranes at term were randomized by sealed envelope into two groups. One group received immediate stimulation of labor with oxytocin infusion. The second group received two prostaglandin E2 (PGE2) 3-mg pessaries 4 hours apart, followed by oxytocin infusion, if necessary. The interval between initiation of therapy to onset of labor was significantly longer in the PG group, but the length of labor was similar in both groups. The maximum dose of oxytocin needed was significantly higher in the oxytocin group. The cesarean delivery rate in the oxytocin group was 14.9%, compared with 19.1% in the PG group (not significantly different). All seven cesareans in the oxytocin group and seven of nine in the PG group were for failed stimulation of labor. Neonatal Apgar scores at 1 and 5 minutes and admission to the neonatal intensive care unit were similar in the two groups. The incidence of maternal and neonatal infection was small and was not different in the two groups. The use of PGE2 3-mg pessaries 4 hours apart, followed by oxytocin infusion if necessary, did not confer any benefit over the use of intravenous oxytocin in obstetric or neonatal outcome when both agents were started a few hours after admission. Labor characteristics after intracervical application of 0.5 mg prostaglandin (PG) E2 gel (n = 83) versus intravenous administration of oxytocin (n = 82) for labor induction were investigated in uncomplicated prolonged pregnancies with unripe cervix. The induction to delivery time as well as the total oxytocin dose were significantly reduced in the PGE2 group (p < 0.001). Cesarean sections, instrumental deliveries and fetal distress had the same frequency, but the failures of trial were significantly higher in the oxytocin group than in the PGE2 group (20.7 vs. 6%, p < 0.01). Twenty-four percent of women needed a second PGE2 dose, and almost half of the women in the PGE2 group experienced 'spontaneous' labor. More neonates in the oxytocin group had 5-min Apgar scores < 7 (p < 0.05). Intracervical PGE2 gel application is superior to intravenous oxytocin in terms of shortening the induction-delivery interval and increasing the frequency of successful vaginal delivery. In addition, it is safe for mother and fetus. A prospective study comparing three management schemes for patients at term with premature rupture of membranes was performed.
                One hundred forty patients were randomized to one of three study groups: prostaglandin E2, placebo, or oxytocin. Patients randomized to prostaglandin E2 and placebo received vaginal suppositories containing 3 mg prostaglandin E2 or glycerin only, respectively; suppositories were administered in a double-blind fashion, on one or two occasions, 6 hours apart. Oxytocin was given only if labor was not established after 12 hours or to augment inadequate labor. In patients randomized to oxytocin labor was induced with intravenous oxytocin. The time interval to delivery, delivery outcome, and complications were analyzed.
                Patients receiving prostaglandin E2 were more likely to be in labor after one suppository and to be delivered without the addition of oxytocin when compared with placebo. The time interval to delivery was shorter with prostaglandin E2 and oxytocin induction versus placebo ("expectant management"). The incidence of maternal infection was lowest in patients with labor induced by prostaglandin E2. Although the overall cesarean section rate was low, there was a trend toward a lower rate with prostaglandin E2 induction. No adverse effects were observed with prostaglandin E2.
                Prostaglandin E2 can be used successfully to induce labor after premature rupture of membranes at term with greater ease of administration when compared with oxytocin. 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 clinical trial was carried out to compare the efficacy and tolerance of two modes of induction of labour: vaginally administered prostaglandin E2 gel vs intravenous perfusion of synthetic oxytocin. Fifty women with pregnancy at or near term in whom prompt vaginal delivery was clinically indicated were divided at random into sub-groups of 25 each. Initial dose of PGE2 gel was 1 mg followed by another application of 1 mg or 2 mg 6 hours later in case active labour stage has not been reached. Progressive oxytocin perfusion began with 1 mU/min., being increased gradually every 20 minutes until efficacious uterine dynamics were attained. Data were recorded on entry of age, parity, gestation age, cervical dilatation, Bishop score, indication for induction. Continuous materno-foetal monitoring was carried out during the induction period. Results were evaluated from induction/delivery time, type of delivery, maternal and foetal condition, and any side-effects which developed. Apart from a higher number of instrumental deliveries in the PGE2 gel series, which was not related to the induction method, there was no significant difference between any of the variables evaluated, both methods producing active labour in approximately 70% of the patients within 12 hours. The authors stress, however, the convenience, both for patients and hospital staff, of the administration of an intravaginal induction agent over a systemic therapeutic method of induction.
Comparison of oxytocin with either intravaginal or intracervical PGE2 reveals that the prostaglandin agents probably increase the chances of achieving vaginal birth within 24 hours. Oxytocin induction may increase the rate of interventions in labour.
A suggestion that for women with prelabour rupture of membranes induction with vaginal prostaglandin may increase risk of infection for mother and baby warrants further study.