Induction of labour: a randomised clinical trial of amniotomy versus amniotomy with oxytocin infusion. Induction of labour: a comparison of a single prostaglandin E2 vaginal tablet with amniotomy and intravenous oxytocin. Early versus late amniotomy for labor induction: a randomized trial. A trial of amniotomy in a Palestinian hospital. A randomised controlled trial of early versus delayed use of amniotomy and oxytocin infusion in nulliparous labour. Induction of labor with and without primary amniotomy. A randomized study of prostaglandin E2 tablets and intravenous oxytocin. Induction of labor with three different techniques at 41 weeks of gestation or spontaneous follow-up until 42 weeks in women with definitely unfavorable cervical scores. Randomised trial comparing a policy of early with selective amniotomy in uncomplicated labour at term. A randomized controlled trial of early amniotomy.
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. 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. 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. This randomised controlled trial of routine amniotomy was carried out in a developing country setting to investigate the effect of this common procedure on the duration of labour, intra-partum interventions and selected newborn and maternal outcomes. In a Jerusalem teaching hospital, 533 multiparous and 157 nulliparous low-risk women were randomised to either amniotomy or intent to conserve membranes. For multiparae, the median duration from randomisation to full dilatation was 95 and 160 min, respectively in the intervention and control arms (p < 0.001); for nulliparae it was 210 and 270 min, respectively (p < 0.001). In both groups, oxytocin was used less in the intervention arms (p < 0.001), and no difference in mode of delivery and immediate outcomes was detected. However, given the risks of this intervention and these study findings indicating an overall short duration of childbirth, amniotomy should be limited to cases of abnormal progress of labour. To compare routine amniotomy and early intravenous oxytocin (active management of labour) with a more selective use of amniotomy and oxytocin in women in true labour who received comparable continuous supportive midwifery care.
                Randomised controlled trial of nulliparous clinic patients in spontaneous labour at term.
                Labour and delivery ward of a university teaching hospital.
                Three hundred and six parturients: 152 received active management of labour; 154 were more selectively managed.
                1. Active management: early amniotomy, early use of oxytocin. 2. Selective intervention management: no routine amniotomy and more selective use of oxytocin.
                Use of oxytocin and amniotomy. Labour duration, mode of delivery.
                Maternal characteristics were comparable in both groups. Amniotomy was more often performed (91% versus 57%, P <0.01) and oxytocin more often used (53% versus 27%, P < 0.01) in the active management group. The first stage of labour, however, was only shortened by half an hour in the active management group (254 min versus 283 min, P = 0.087). Caesarean section rate (3.9% versus 2.6%), spontaneous vaginal delivery rate (78% versus 79%) and neonatal outcome were not significantly different between groups.
                Within a set-up of strict labour diagnosis and supportive midwifery care, routine amniotomy and early use of oxytocin offered no advantage over a more selective use of amniotomy and oxytocin in terms of mode of delivery and labour duration. A comparative study of labor induction has been performed on 471 consecutive patients. Primary amniotomy was performed in 227 cases, and 103 of these patients were stimulated, 57 patients with PGE2 tablets and 46 with oxytocin. In the remaining 124 cases labor was induced within 4 hours without medical stimulation. Primary amniotomy was omitted in 244 cases, as the head was not engaged and the cervix was unripe. After random allocation to the treatment groups 125 patients received PGE2 tablets (ProstinR), and 119 patients received oxytocin intravenously. After 2 days of stimulation without primary amniotomy, delivery was induced in 83 per cent of the patients receiving PGE2 and in 84 per cent of the patients receiving oxytocin. All patients on whom primary amniotomy had been performed were delivered on the first day. There was no difference in the success rate between PGE2 and oxytocin treatments in patients with the same Bishop score. The performance of amniotomy at the beginning of induction led to a significantly lower total dose as well as a lower maximal dose of PGE2 and oxytocin. There was no difference in the duration of active labor in patients receiving PGE2 or oxytocin. There were no differences in the incidence of fetal distress and low Apgar scores between the different groups. No serious side effects occurred. Vomiting and diarrhea in 14 patients (8 per cent) receiving PGE2 was in contrast to 3 patients with these symptoms (2 per cent) in the oxytocin group. Oral administration of PGE2 is a convenient, effective and safe alternative to oxytocin for the induction of labor; however, PGE2 was not found superior to oxytocin in cases with a low Bishop score. To compare the obstetric outcome of induction of labor at 41 weeks and of follow-up until 42 weeks and induction if the patient has still not given birth at 42 weeks.
                Six hundred women at 287+/-1 days of gestation with definitely unfavorable cervical scores were randomized to labor induction (N=300) or spontaneous follow-up (N=300) with twice-weekly nonstress testing and amniotic fluid measurement and once-weekly biophysical scoring. The treatments used in the induction group were (1) vaginal administration of 50 microg misoprostol (n=100), (2) oxytocin induction (n=100), and (3) transcervical insertion of a Foley balloon (n=100). The primary outcome measures were the cesarean delivery rate, whether or not the normal hospital stay had to be extended, and the neonatal outcomes. Secondary outcome measure included number of emergency cesarean deliveries performed for abnormalities of the fetal heart rate (FHR).
                The abdominal delivery rate was 19.3% in the induction group and 22% in the follow-up group (p=0.4). The mean length of hospital stay in the two main groups was 1.4+/-0.8 days and 1.3+/-1 days, respectively (p=0.1). Significantly higher rates of macrosomia and shoulder dystocia were seen in the follow-up group (24.6 and 2.3%) than in the induction group (7.6%, p<0.001; 0.3%, p=0.03). Meconium-stained amniotic fluid and meconium aspiration syndrome were observed significantly less frequently in the induction group (9.3 and 1.3%) than in the follow-up group (20.3%, p<0.001; 4%, p=0.03). Rates of emergency abdominal delivery in response to worrying FHR traces, neonatal intensive care unit admission, and low umblical artery pH were similar in the two groups. There was one intrauterine fetal death in the follow-up group.
                Induction of labor at 41 weeks of gestation does not increase the cesarean delivery rate or cause a longer stay in hospital than follow-up until 42 weeks, and neonatal morbidity is also lower after induction. To compare two management policies: rupture of the fetal membranes when women are in normal labour or leave them intact as long as feasible.
                The labour ward of a city university hospital.
                Automated randomised clinical trial.
                1540 women in uncomplicated term labour. Data on labour duration, blood loss, oxytocin use and fetal condition were collected from 1132 women. Some data from nulliparous women has been presented earlier by the UK Amniotomy Group.
                Duration of labour, Apgar score, fetal morbidity and maternal morbidity including perineal injury, mode of delivery, epidural rates and the total number of vaginal examinations in the first stage of labour after amniotomy.
                Amniotomy at the next vaginal examination or amniotomy only if indicated. The median cervical dilatation at membrane rupture was 2 cm greater in the first group.
                A policy of routine amniotomy in labour had no measurable advantage over selective amniotomy for parous women (difference = 4 min) but shortened labour in nulliparous women by 1 h (Mann-Whitney U test: P < 0.05). There was a suggestion of a higher caesarean section rate (OR 1.9; 95% CI 0.9-3.5), and there were more vaginal examinations after membrane rupture in the group allocated routine amniotomy. There were no measurable differences in oxytocin use, fetal condition at birth, retained placenta rates, blood loss, pain or analgesia requirements.
                Routine amniotomy may shorten the first labour but not subsequent ones. There is a suggestion that routine surgical interference may be harmful by increasing the risk of caesarean section, and this agrees with data from other trials (common odds ratio 1.2; 95% CI 0.92-1.6). OBJECTIVE-To determine if a policy of early amniotomy resulted in a reduction in mean labour duration when compared to a policy of conservation of the membranes. DESIGN-A single-centre randomized controlled trial. SETTING-A tertiary care teaching hospital in Alberta, Canada. SUBJECTS-Ninety-seven term nulliparae in spontaneous labour, baby in cephalic presentation. INTERVENTION-Early amniotomy versus intent to keep membranes intact. MAIN OUTCOME MEASURES-Interval from randomization to delivery, rate of abnormalities of fetal heart rate tracings, cord artery blood pH, Apgar scores. RESULTS-The mean interval from randomization to delivery was 390.9 (SE 29.1) min in the amniotomy group and 442.9 (SE 34.1) min in the control group (P = 0.251). There were no differences between groups in the occurrence of fetal heart rate tracing abnormalities, nor was there a difference in the proportion of babies with abnormal Apgar scores, or abnormal cord pH (less than 7.20). CONCLUSION-The results of the study fail to support the long held belief that early amniotomy is an effective method for reducing labour duration.
Data are lacking about the value of amniotomy alone for induction of labour. While there are now other modern methods available for induction of labour (pharmacological agents), there remain clinical scenarios where amniotomy alone may be desirable and appropriate, and this method is worthy of further research. This research should include evaluation of the appropriate time interval from amniotomy to secondary intervention, women and caregivers' satisfaction and economic analysis.
[Note: the two citations in the awaiting classification section of the review may alter the conclusions of the review once assessed.]