Induction of labour with a viable infant: a randomised clinical trial comparing intravaginal misoprostol and intravaginal dinoprostone

Efficacy and safety of six hourly vaginal misoprostol versus intracervical dinoprostone: a randomized controlled trial

OBJECTIVE

To compare the efficacy and safety of intravaginal misoprostol versus dinoprostone cervical gel for cervical ripening and labour induction.

METHODS

We carried out an experimental clinical trial in which we enrolled 130 cervical consecutive patients with cervical ripening, randomly assigned to one of the following two treatment groups: (1) intravaginal misoprostol and (2) intracervical dinoprostone gel. A total of 50 microm of misoprostol was placed in the posterior vaginal fornix every 6 h for a maximum period of 24 h and 0.5 mg of dinoprostone was administrated in the uterine cervix every 6 h, for a maximum period of 24 h. The primary outcome measure was the number (rate) of women who went to vaginally deliver within 24 h of the protocol initiation.

RESULTS

Among 130 patients evaluated, 65 were allocated to the misoprostol group and 65 to the dinoprostone group. The proportion of vaginal delivery within 24 h was significantly higher in the misoprostol group (75%) than in the dinoprostone group (53.8%) (RR = 1.40, 95% CI [1.07-1.45], P = 0.02). There was no significant difference between the mean time interval of delivery in the misoprostol group and the dinoprostone group (14.9 vs.15.8 h) (P = 0.51). The Bishop score was significantly higher in the misoprostol group, 6 h after the onset of the study (1.38; relative risk, 95% CI [1.02-1.85], P = 0.03). The Caesarean delivery rate for fetal distress was higher in the dinoprostone group (21 vs. 10.8%, P = 0.15). The tachysystole (Misoprostol 6.1% vs. dinoprostone 4.6%, relative risk 1.15, 95% CI [0.6-2.24]) and hyperstimulation syndrome rates (Misoprostol 7.6% vs. dinoprostone 4.6%, relative risk 1.26, 95% CI [0.72-2.24]) were slightly increased in the misoprostol group than in the dinoprostone group without reaching the level of statistical signification.

CONCLUSION

Misoprostol as used in this protocol is more effective than cervical dinoprostone gel application in the cervical ripening and labour induction. There is a tendency for an increase in the rate of tachysystole and hyperstimulation syndrome.

A prospective, randomized comparison of vaginal misoprostol versus intra-amniotic prostaglandins for midtrimester termination of pregnancy

OBJECTIVE

The purpose of this study was to compare the efficacy and adverse effects of vaginal misoprostol and intra-amniotic PGF2alpha for midtrimester abortion.

STUDY DESIGN

One hundred thirty-two women between 12 and 24 weeks' gestation, seeking abortion in a tertiary hospital, were randomized to receive vaginal misoprostol (400 microg every 3 hours) or intra-amniotic PGF2alpha (carboprost 1.5 mg). Main outcome measures were induction-to-abortion interval, success rates at 24 and 48 hours, and adverse effects.

RESULTS

Successful abortion rates at 24 and 48 hours between intra-amniotic PGF2alpha and vaginal misoprostol were not statistically different. However, vaginal misoprostol results in a significantly shorter mean induction-to-abortion interval, compared with intra-amniotic PGF2alpha (misoprostol: 16.2 hours; intra-amniotic PGF2alpha: 20.8 hours; P = .006), particularly among multiparous women (misoprostol: 13.1 hours; intra-amniotic PGF2alpha 18.3 hours; P = .011) and for gestation below 130 days (misoprostol: 14.6 hours; intra-amniotic PGF2alpha: 20.2 hours; P = .015). Fever and shivering were commoner with vaginal misoprostol.

CONCLUSION

Vaginal misoprostol should be the regimen of choice for midtrimester abortion, particularly for multiparous women and women in the early second trimester.

Comparaison du score de Bishop et de la mesure échographique de la longueur du col dans la prédiction du risque de césarienne avant maturation du col par prostaglandines

OBJECTIVE

To compare pre-induction ultrasonographic cervical length and Bishop score in predicting risk of caesarean section after labor induction with prostaglandins.

PATIENTS AND METHODS

Assessment of the Bishop score and measurement of the cervical length by transvaginal sonography were performed by two operators, blinded to each other's results among women with singleton pregnancies at between 34(+0) - 41(+3) weeks of gestation requiring induction of labor with prostaglandins for medical indications. Fisher's exact test and regression logistic models were used for statistics analysis. In order to measure the strength of the association between ultrasonographic cervical length or Bishop score on one hand, and the caesarean sections rate (global or for failed induction or failure to progress) on the other hand, we computed odds ratios with 95% confidence interval.

RESULTS

Among the 266 patients included in the study, multivariate analysis has shown that only Bishop score was predictive for the global caesarean section risk (OR [95% CI] 0.63 [0.45-0.87] ; P =0.005). However, neither Bishop score (OR [95% CI] 0.68 [0.42-1.09] ; P =0.11), nor ultrasonographic cervical length (OR [95% CI] 1.01 [0.95-1.08] ; P =0.59) was predictive for failed induction or failure to progress caesarean section risk.

DISCUSSION AND CONCLUSION

The Bishop score appears to be a better predictor of the global caesarean section risk than ultrasonographic cervical length after induction of labor for medical reasons.

Sample size formula for proportional hazards modelling of competing risks

To test the effect of a therapeutic or prognostic factor on the occurrence of a particular cause of failure in the presence of other causes, the interest has shifted in some studies from the modelling of the cause-specific hazard to that of the subdistribution hazard. We present approximate sample size formulas for the proportional hazards modelling of competing risk subdistribution, considering either independent or correlated covariates. The validity of these approximate formulas is investigated through numerical simulations. Two illustrations are provided, a randomized clinical trial, and a prospective prognostic study.