A comparison of 100 microg oral misoprostol every 3 hours and 6 hours for labor induction: a randomized controlled trial

What is the optimal duration of oral misoprostol treatment for cervical ripening?

OBJECTIVES

To evaluate the number of misoprostol tablets needed to obtain a Bishop score (BS) ≥ 6 or a significant cervical change (≥2 points in BS) during cervical ripening.

METHODS

Retrospective study of women with term singleton pregnancies and a BS < 6 taking oral misoprostol (20 μg first 2 doses followed by 40 μg every 2 h) for cervical ripening.

RESULTS

We included 400 women, 72% nulliparous, mean age of 31.3 ± 5.9 years and 70% with a baseline BS ≤ 2. During cervical ripening, 61 (15.3%) achieved a BS ≥ 6 and 205 (51.3%) a significant change in BS. The incremental risk to achieve a BS ≥ 6 after 4 tablets was low (+3.25%) with an incremental probability of +12.75% for painful uterine contractions and +0.5% for abnormal fetal tracing (AFT). The incremental probability to achieve a significant change in BS after 7 tablets was low (+2.0%). 24.3% women delivered by cesarean section which likelihood significantly increased with maternal age <35 years, BMI ≥ 30, nulliparity, AFT, and baseline BS ≤ 2.

CONCLUSIONS

The marginal benefit of giving more than 7 misoprostol tablets (14 h) during cervical ripening is very low.

Oral misoprostol for induction of labour

BACKGROUND

Misoprostol is an orally active prostaglandin. In most countries misoprostol is not licensed for labour induction, but its use is common because it is cheap and heat stable.

OBJECTIVES

To assess the use of oral misoprostol for labour induction in women with a viable fetus.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (17 January 2014).

SELECTION CRITERIA

Randomised trials comparing oral misoprostol versus placebo or other methods, given to women with a viable fetus for labour induction.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial data, using centrally-designed data sheets.

MAIN RESULTS

Overall there were 76 trials (14,412) women) which were of mixed quality.In nine trials comparing oral misoprostol with placebo (1109 women), women using oral misoprostol were more likely to give birth vaginally within 24 hours (risk ratio (RR) 0.16, 95% confidence interval (CI) 0.05 to 0.49; one trial; 96 women), need less oxytocin (RR 0.42, 95% CI 0.37 to 0.49; seven trials; 933 women) and have a lower caesarean section rate (RR 0.72, 95% CI 0.54 to 0.95; eight trials; 1029 women).In 12 trials comparing oral misoprostol with vaginal dinoprostone (3859 women), women given oral misoprostol were less likely to need a caesarean section (RR 0.88, 95% CI 0.78 to 0.99; 11 trials; 3592 women). There was some evidence that they had slower inductions, but there were no other statistically significant differences.Nine trials (1282 women) compared oral misoprostol with intravenous oxytocin. The caesarean section rate was significantly lower in women who received oral misoprostol (RR 0.77, 95% CI 0.60 to 0.98; nine trials; 1282 women), but they had increased rates of meconium-stained liquor (RR 1.65, 95% CI 1.04 to 2.60; seven trials; 1172 women).Thirty-seven trials (6417 women) compared oral and vaginal misoprostol and found no statistically significant difference in the primary outcomes of serious neonatal morbidity/death or serious maternal morbidity or death. The results for vaginal birth not achieved in 24 hours, uterine hyperstimulation with fetal heart rate (FHR) changes, and caesarean section were highly heterogenous - for uterine hyperstimulation with FHR changes this was related to dosage with lower rates in those with lower doses of oral misoprostol. However, there were fewer babies born with a low Apgar score in the oral group (RR 0.60, 95% CI 0.44 to 0.82; 19 trials; 4009 babies) and a decrease in postpartum haemorrhage (RR 0.57, 95% CI 0.34 to 0.95; 10 trials; 1478 women). However, the oral misoprostol group had an increase in meconium-stained liquor (RR 1.22, 95% CI 1.03 to 1.44; 24 trials; 3634 women).

AUTHORS' CONCLUSIONS

Oral misoprostol as an induction agent is effective at achieving vaginal birth. It is more effective than placebo, as effective as vaginal misoprostol and results in fewer caesarean sections than vaginal dinoprostone or oxytocin.Where misoprostol remains unlicensed for the induction of labour, many practitioners will prefer to use a licensed product like dinoprostone. If using oral misoprostol, the evidence suggests that the dose should be 20 to 25 mcg in solution. Given that safety is the primary concern, the evidence supports the use of oral regimens over vaginal regimens. This is especially important in situations where the risk of ascending infection is high and the lack of staff means that women cannot be intensely monitored.

Misoprostol to induce labour: a review of its use in a NSW hospital

BACKGROUND

Induction of labour (IOL) is a common procedure in maternity care. Misoprostol is a prostaglandin E(1) analogue that is effective, cheap and easily stored but not licensed for this use in Australia. Despite evidence supporting the use of misoprostol for IOL, few Australian maternity units use it.

AIMS

To review the outcomes of women who received vaginal misoprostol for IOL.

METHODS

A retrospective review of all births induced with vaginal misoprostol from July 1998 to October 2005 at one hospital in New South Wales. Women who had an IOL for multiple pregnancy, known fetal death or congenital abnormality were excluded.

RESULTS

In total, 1998 women with a normal, viable, single fetus received vaginal misoprostol for IOL. More than half (57%) of women did not require augmentation during labour. More than one third (37%) had epidural analgesia, 25% had an emergency Caesarean section, 7% had a post-partum haemorrhage and 16% of babies were admitted to the special care nursery. Uterine rupture occurred in two women, one of whom had a history of uterine surgery. There were two neonatal deaths, both because of Group B Streptococcus infection.

CONCLUSIONS

In this cohort of women, misoprostol was an effective and safe agent to induce labour. Recent legal concerns at this hospital make its future use in normal clinical practice unlikely.

Oral misoprostol for induction of labour

BACKGROUND

Misoprostol is a synthetic prostaglandin that can be given orally or vaginally. In most countries misoprostol has not been licensed for use in pregnancy, but its unlicensed use is common because misoprostol is cheap, stable at room temperature and effective in causing uterine contractions. Oral use of misoprostol may be convenient, but high doses could cause uterine hyperstimulation and uterine rupture which may be life-threatening for both mother and fetus.

OBJECTIVES

To assess the effectiveness and safety of oral misoprostol used for labour induction in women with a viable fetus in the third trimester of pregnancy.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (January 2005).

SELECTION CRITERIA

Randomised trials comparing oral misoprostol versus other methods, placebo or no treatment, given to women with a viable fetus for labour induction.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed trial quality and extracted data, using centrally-designed data sheets.

MAIN RESULTS

Forty-one trials (8606 participants) were included. In four trials comparing oral misoprostol with placebo (474 participants), women using oral misoprostol were less likely to have long labours (relative risk (RR) 0.16, 95% confidence interval (CI) 0.05 to 0.49), needed less oxytocin (RR 0.32, 95% CI 0.24 to 0.43) and had a lower caesarean section rate (RR 0.62, 95% CI 0.40 to 0.96). In nine trials comparing oral misoprostol with vaginal dinoprostone (2627 participants), women given oral misoprostol were less likely to need a caesarean section, but this reduction reached statistical significance only in the subgroup with intact membranes (RR 0.78, 95% CI 0.66 to 0.94). Uterine hyperstimulation was more common after oral misoprostol (RR 1.63, 95% CI 1.09 to 2.44) although this was not associated with any adverse fetal events. Seven trials (1017 participants) compared oral misoprostol with intravenous oxytocin. The only difference between the groups was an increase in meconium-stained liquor in women with ruptured membranes following administration of oral misoprostol (RR 1.72, 95% 1.08 to 2.74). Sixteen trials (3645 participants) compared oral and vaginal misoprostol and found no difference in the primary outcomes. There was less uterine hyperstimulation without fetal heart rate changes in those given oral misoprostol (RR 0.37, 95% 0.23 to 0.59). Oral misoprsotol was associated with increased need for oxytocin augmentation (RR 1.28, 95% 1.11 to 1.48) and more meconium-stained liquor (RR 1.27, 1.01 to 1.60).

AUTHORS' CONCLUSIONS

Oral misoprostol appears to be more effective than placebo and at least as effective as vaginal dinoprostone. However, there remain questions about its safety because of a relatively high rate of uterine hyperstimulation and the lack of appropriate dose ranging studies. In countries where misoprostol remains unlicenced for the induction of labour, many practitioners will prefer the legal protection of using a licenced product like dinoprostone. There is no evidence that misoprostol given orally is inferior to the vaginal route and has lower rates of hyperstimulation. If misoprostol is used orally, the dose should not exceed 50 mcg.

Induction of labor with 50 and 100μg of misoprostol: comparison of maternal and fetal outcomes

OBJECTIVE

The aim of this randomized controlled study was to compare the efficacy and the safety of different regimens of misoprostol for labor induction. MATERIALS AND METHODS Eligible women received intravaginal 100 microg, every 6 h or 50 microg every 4 h. Treatment continued until: (1) dilatation >3 cm; (2) rupture of membranes (artificial); (3) signs of uterine hyperstimulation; (4) adequate contraction pattern (three contraction/10 min). Managing clinician might use oxytocin during labor. Cesarean section rate was the main outcome that was considered variably. Other outcome measures were neonatal outcome (Apgar scores, meconium staining, and umbilical artery pH) and induction to delivery interval.

RESULTS

A total number of 72 women received either misoprostol 100 microg (n=37), or 50 microg (n=35) randomly. The two groups had similar mean Bishops scores at induction (4.10+/-2.4 versus 4.2+/-2.1; P=0.85), rates of nulliparity, use of epidural anesthesia, and oxytocin augmentation. In two groups the number of doses of misoprostol used was similar (1.6+/-0.5 versus 1.7+/-0.3)

CONCLUSION

There was not any difference between the two groups in the mean+/-S.D. time to delivery (h) and cesarean rate. Likewise, there was not a significance between two groups in the rates of 5 min Apgar score, and of meconium passage.