Comparison of methods
The outcomes for the various methods of induction are similar, and this has led to diverse practice worldwide. The choice of one over the other is usually based on side effects, location of induction (inpatient versus outpatient), local experience with the technique, availability of monitoring facilities, patient and provider preference, and cost.
It is important therefore to look at the data which compares each method so as to enable a rational choice of induction method for each occasion.A network meta-analysis (a systematic review method for multiple simultaneous comparisons) attempted to compare the use of the Foley catheter, misoprostol (vaginal and oral), and dinoprostone (vaginal and cervical) in a single review for women with intact membranes (46). In 96 randomized trials, they found that vaginal misoprostol was the most effective cervical ripening method to achieve vaginal delivery within 24 hours, but had the highest incidence of uterine hyperstimulation with fetal heart rate changes. The use of a Foley catheter to induce labour was associated with the lowest rate of uterine hyperstimulation accompanied by fetal heart rate changes. The caesarean section rate was lowest using oral misoprostol for the induction of labour. Sensitivity analysis showed that the results were unaltered with the exclusion of high-dosage regimens. The authors concluded that no method of labour induction demonstrated overall superiority and that decisions regarding the choice of induction method should depend upon the relative importance of the outcomes.
Alfirevic et al. also conducted a much more extensive network meta-analysis of 280 randomized trials, but examined only prostaglandin induction methods (47). They found that low-dose (a discussion of cost, misoprostol is the cheapest medication. Foley catheters follow behind closely but can become more expensive if the bespoke double-balloon version is desired. Dinoprostone is most expensive but has different prices based on the different formulations. The immediate-acting gel is less expensive than the extended-release preparation (slow-eluting tampon). A new vaginal insert version of misoprostol which is 200 mcg and meant to be a corollary to the slow- eluting dinoprostone tampon was shown to significantly reduce time to delivery in comparison to the dinoprostone version but with increased rates of hyperstimulation and fetal heart rate abnormalities (48). It is only available in some countries and is near in price to the dinoprostone slow-eluting tampon.