Discussion
PROM, hyperstimulation, infection, rupture, foetal distress, IOL, intraamniotic infection
INFECTION IN THE NEONATE, IOL, CONTRACTIONS, INFECTION, SECONDARY, FOETAL DISTRESS, HEAT, COMPLICATIONS
This randomized trial aimed to compare the efficacy and safety of oral misoprostol versus oxytocin infusion for IOL in pregnant women with term PROM. The study revealed that both misoprostol and oxytocin are effective and safe for IOL. However, we found that patients induced by misoprostol took significantly-less time to reach active phase with a shorter induction to delivery interval as compared to patients induced with oxytocin. This difference was clear in multiparous women, but not observed in primiparous women when subgroup analysis was done.IOL has been managed using a variety of techniques, both medicinal and mechanical, each having advantages and disadvantages. Prelabor ROMs is a unique indication for IOL, and we need a technique that works quickly to prevent prolonged ROMs and potential foetal distress or intraamniotic infection.Misoprostol, a synthetic prostaglandin E1 analogue, is employed to promote uterine contractions and cervical ripening. It has the benefits of being affordable, readily available, and heat stable [Throughout labour and the postpartum period, oxytocin naturally promotes uterine contractions. Its synthetic analogues are commonly used for both induction and augmentation of labour [In our study, there was no significant difference between the two agents in obtaining high rates of vaginal delivery (82.4% and 87.1% for the misoprostol group and the oxytocin group, respectively). This was similarly observed in the review by Lin et al as they concluded that misoprostol is an effective and safe agent for IOL in women with term PROM, and when compared with oxytocin, the risk of hyperstimulation and the rate of maternal and neonatal complications were similar [As regards the time taken to deliver, we found that misoprostol group had shorter total induction to delivery interval, an effect that was noted only in multiparous and not primiparous women when subgroup analysis was employed. When Unthanan et al. compared sublingual misoprostol to oxytocin for IOL in 170 pregnant women with term PROM, they came to similar conclusions. They found that induction time and cesarean section rates of sublingual misoprostol group were significantly lower than the intravenous oxytocin group [Although IOL in cases with PROM is a bit different from IOL in cases without PROM (as the local prostaglandins released might affect the degree of the cervical ripening and might have a role in augmenting the uterine contractions); it is worth mentioning some results of other studies comparing misoprostol to oxytocin in IOL in cases without PROM. De Aquino and Cecatti compared misoprostol to oxytocin for IOL in term pregnant women with intact membranes. They randomized 210 patients to either intravaginal 25μg misoprostol every 4 h (maximum 8 doses) or intravenous oxytocin continuous infusion. They concluded that misoprostol was more efficient for cervical ripening and labor induction than oxytocin [Our study’s key strength is that it exclusively included patients with PROM; thus, it would help to cover the gap of knowledge as regards the best method of IOL in this subset of patients with special situation being more susceptible to infection, and to possible hyperstimulation due to release of endogenous prostaglandins along with rupture of the membranes.Our study does, however, have certain drawbacks. Although there was a statistically significant difference in the induction-delivery interval, its clinical significance is yet to be determined. We did not measure markers of possible infection in the neonates; only an overall assessment of the neonate by the Apgar score and NICU admission.Another issue is that blinding was not applicable (both the physician and the patient knew which intervention was being used). However, this might not be a concern, as the outcomes we measured were not subjective, but objective outcomes not affected by bias, neither from the observer or the patient.One other thing: in the group who were induced by oxytocin, the oxytocin infusion was maintained as such till delivery. As for the group induced by misoprostol, oxytocin was not used for augmentation of labour, and if used, the patient was excluded from the study analysis. We acknowledge that this might have implications on the time from active phase till delivery; however, the time from starting induction till reaching the active phase was also measured as one of the secondary outcomes, so it can be used to correctly compare the two interventions as head-to-head comparison. Starting IOL with misoprostol and continuing it with oxytocin is a widespread practice. Hence, more investigations are required to determine whether or not this will be superior. Another point which might have implications on the measures of time to delivery is the type and dose of the analgesic used during labour. Some patients received opiates, others did not. Unfortunately, this data was not collected (which patients took which drug in which dose). Whether this would change the results significantly or not, is not clear.