Early versus late amniotomy for labor induction: a randomized trial. Induction of labour: a randomised clinical trial of amniotomy versus amniotomy with oxytocin infusion. Intrauterine pressures in labours induced by amniotomy and oxytocin or vaginal prostaglandin gel compared with spontaneous labour. A randomized controlled trial of selective planned delivery. [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]. Assessment of a new prostaglandin E2 gel in labour induction. Induction of labour: a comparison of a single prostaglandin E2 vaginal tablet with amniotomy and intravenous oxytocin. A randomized comparison of vaginal prostaglandin E2 with oxytocin plus amniotomy for induction of labour in women with intermediately ripe cervices. Single shot prostaglandin gel for labor induction. Induction of labour at term in primigravidae with low Bishop's score: a comparison of three methods.
Our purpose was to determine the impact of early and late amniotomy on labor induction with continuous oxytocin infusion at term.
                A total of 209 women admitted for labor induction were randomized to early or late amniotomy. The early amniotomy group (n = 106) had membranes ruptured as soon as it was deemed safe and feasible. The late amniotomy group (n = 103) had membrane rupture performed at > or = 5 cm dilatation. The first 103 women received a continuous oxytocin infusion with incremental adjustments at 60-minute intervals as required. The next 106 women had adjustments every 30 minutes as required. Statistical analysis was confined to concurrent groups.
                Early amniotomy was associated with shorter labor (13.3 vs 17.8 hours, p = 0.001), chorioamnionitis (22.6% vs 6.8%, p = 0.002), and significant fetal umbilical cord compression (12.3% vs 2.9%, p = 0.017). The benefit regarding shortening of labor was limited to women having oxytocin increments every 30 minutes as required (13.3 vs 17.8 hours, p = 0.001). Alternatively, the increase in chorioamnionitis was confined to the 60-minute group (39% vs 11%, p < 0.001), which also demonstrated a trend toward increased moderate and severe variable decelerations (19.6% vs 6.4%, p = 0.08).
                When a protocol of 60-minute increments in oxytocin infusion rate is desired, amniotomy should be performed late in labor to reduce chorioamnionitis and significant umbilical cord compression. Alternatively, if early amniotomy is necessary, oxytocin should be adjusted every 30 minutes as tolerated. To compare two methods of induction of labour-amniotomy with oxytocin infusion versus amniotomy alone.
                Prospective randomised clinical trial.
                The department of obstetrics in a Swedish central hospital.
                One hundred and ninety-six pregnant women with indication for induction of labour at term and a favourable cervix (modified Bishop score > or = 6).
                The women were randomised to amniotomy followed by oxytocin infusion after 1 h (group A, n = 98) or amniotomy alone (group B, n = 98). If labour had not ensued on the following morning, after approximately 24 h, the women in group B were given an oxytocin infusion.
                Induction-delivery interval, duration of labour, time spent in delivery ward, oxytocin use, maternal and neonatal clinical outcome.
                Amniotomy combined with early oxytocin infusion resulted in shorter induction-delivery interval (median 6.0 h; 95% confidence interval (CI) 5.0 to 6.5 h) than amniotomy alone (median 9.0 h; 95% CI 7.5 to 10.0 h). This was due to a shorter latent period in the former group (median 2.3 h; 95% CI 2.0 to 3.0 h) compared to the latter (median 4.3 h; 95% CI 3.0 to 5.5 h). The duration of labour stages 1 and 2 were similar in both groups. The time spent in the delivery ward was slightly reduced for women managed by amniotomy alone (median 5.0 h; 95% CI 4.5 to 6.0 h) compared with those managed by the combination of amniotomy and oxytocin infusion (median 6.0 h; 95% CI 5.0 to 6.5 h). Eighty-seven percent in group A and 32% in group B were given oxytocin, and the total oxytocin infusion time was nearly five times longer in group A. No other important effect on maternal or fetal outcomes was demonstrated.
                With regard to safety the results do not warrant recommending either type of labour induction. The minor differences observed between the induction groups justify an individual management policy, with attention paid to both the indication for induction of labour and the woman's choice. Uterine activity during the first stage of labour was measured by an intrauterine transducer in 22 women induced with intravaginal PGE2 gel, in 37 induced by amniotomy and intravenous oxytocin, and in nine women in spontaneous labour. The nulliparous women in the PGE2 gel group had a significantly longer pre-established phase of labour and a significantly shorter established phase than nulliparae induced by amniotomy and oxytocin. The mean levels of total uterine activity (kPas) during labour and the uterine activity integrals (kPas/15 min) were significantly lower in nulliparae induced with PGE2 gel than in those induced by amniotomy and oxytocin. These findings suggest that PGE2 gel has a positive, beneficial effect on cervical compliance during the pre-established phase, resulting in less myometrial effort during established labour. These effects were less evident in parous women, probably because of an innate lower cervical resistance due to their previous labours. Uterine activity patterns during the 4 h leading to full cervical dilatation in nulliparae were similar in labours induced with PGE2 gel and spontaneous labours, whereas labours induced by amniotomy and oxytocin exhibited a significantly different pattern. Expulsion of the fetus during normal labour is a function of both uterine contractions and a decrease in the cervical resistance and the data suggest that induction by PGE2 gel more closely mimics spontaneous labour, whereas the predominant effect of oxytocin is to stimulate myometrial activity. A prospective randomized controlled trial designed to investigate selective planned delivery is reported: 264 obstetrically normal women in the 38th week of pregnancy were admitted to this trial and 184 completed it. The infants of mothers in the planned delivery group had higher serum bilirubin levels on the fifth day post partum than control infants but no baby required treatment for hyperbilirubinaemia. Mothers in the planned delivery group required significantly greater amounts of pethidine while control mothers had a significantly higher incidence of meconium staining of the amniotic fluid. However, the infants in the two groups had similar Apgar scores at birth. There was one stillbirth in the control group; this was due to unrecognized fetal hypoxia during labour induced at 42 weeks for postmaturity. 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. Prostaglandin E2 in a new gel form (Prepidil; Upjohn) was found to be as efficient in inducing labour as artificial rupture of membranes combined with intravenous oxytocin administration. There were no side-effects in the 25 patients in the study group. Prepidil gel has the advantage of simplicity and patient acceptance. In a randomized controlled study of 100 women of low parity and favourable induction features, induction of labour by means of a single vaginal tablet containing 3 mg of prostaglandin E2 (PGE2) was compared with the conventional method of amniotomy and intravenous oxytocin. Four of the patients (8%) who received the prostaglandin tablet required additional intravenous oxytocin to achieve delivery. The prostaglandin group had a longer mean overall induction-delivery interval but a shorter amniotomy-delivery interval than the oxytocin group. One patient in the PGE2 group and two in the oxytocin group required caesarean section. The PGE2 treated patients expressed a higher level of satisfaction with their method of induction, they required less analgesia, had less blood loss at delivery and their babies had a lower incidence of neonatal jaundice. To compare the effects of oxytocin and amniotomy or vaginal prostaglandin E2 (PGE2) for induction of labour.
                We conducted a randomized clinical trial. Eligible for the trial were women with normal pregnancy, parity 0-3, with intact membranes, >40 weeks of gestation documented by ultrasound examination before 20 weeks gestation, observed in a network of 13 general and teaching hospitals in Italy. Inclusion criteria were cervical Bishop's score 5-7, less than six uterine contractions per hour, single pregnancy, cephalic presentation, no history of cesarean section and uterine surgery. Eligible women were randomly assigned by phone to oxytocin plus amniotomy (163 women) or vaginal PGE2 2 mg, two doses at 6-h intervals (157 women).
                Overall, 50 women (15.6%) delivered by cesarean section, 22 (13.5%) randomized to oxytocin, and 28 (17.8%) randomized to PGE2 (not significant). Twelve hours after randomization, induction had failed in 26 women of the 163 randomized to oxytocin plus amniotomy (21.6%) and 34 out of the 157 randomized to PGE2 (15.9%): the difference was not significant. Neonatal outcome was similar in the two groups.
                This study did not find marked differences in labour and neonatal outcome between women randomized to oxytocin plus amniotomy or vaginal PGE2. A shorter induction delivery interval in the group receiving amniotomy and oxytocin after PGE2 priming was observed. A viscous suspension of prostaglandin E2 was introduced endocervically to induce labor in patients with favourable induction features. The method was found to be effective and compared favourably with the conventional practices of amniotomy and intravenous oxytocin infusion or oral prostaglandin therapy. Several advantages were found including a high degree of patient acceptability. To determine which of three methods of induction of labour at term in primigravidae with a low Bishop's score is effective and safe.
                Random allocation to Prostin E2 and amniotomy later (Group A); low amniotomy and oxytocin titration (Group B); and intra-cervical Foley balloon overnight followed next morning by low amniotomy and oxytocin titration (Group C).
                Primigravidae (n = 90) in the University Hospitals, Benin City, Nigeria.
                (i) Time taken to achieve 3 uterine contractions in 10 min; (ii) induction-delivery interval.
                The mean time interval between intervention and regular uterine contractions was shortest in Group C (A vs. C, P < 0.02; A vs. B, P < 0.02). The mean induction-delivery interval was shortest in Group C (11.1 h) followed by Group B (13.9 h) and Group C (17.9 h) P < 0.05-0.001.
                The induction-delivery interval was shortest when using a Foley catheter for cervical ripening followed by amniotomy and oxytocin titration.
Data on the effectiveness and safety of amniotomy and intravenous oxytocin are lacking. No recommendations for clinical practice can be made on the basis of this review. Amniotomy and intravenous oxytocin is a combination of two methods of induction of labour and both methods are utilised in clinical practice. If their use is to be continued it is important to compare the effectiveness and safety of these methods, and to define under which clinical circumstances one may be preferable to another.
[Note: The three citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]