Misoprostol administered sublingually at a dose of 12.5 μg versus vaginally at a dose of 25 μg for the induction of full-term labor: a randomized controlled trial

Abstract

Background: Labor induction is defined as any procedure that stimulates uterine contractions before labor begins spontaneously. The vaginal and oral routes of administration of misoprostol are those most used for the induction of labor in routine practice, with the recommended dose being 25 μg. Nevertheless, the sublingual route may reduce the number of vaginal examinations required, increasing patient comfort and lowering the risk of maternal and fetal infection. Based on a previous systematic review, the objective of this study was to compare the frequency of tachysystole as the main outcome measure when misoprostol is administered sublingually at the dose of 12.5 μg versus vaginally at a dose of 25 μg to induce labor in a full-term pregnancy with a live fetus. Methods: A randomized, placebo-controlled, triple-blind clinical trial was conducted at two maternity hospitals in northeastern Brazil. Two hundred patients with a full-term pregnancy, a live fetus, Bishop score ≤ 6 and an indication for induction of labor were included. Following randomization, one group received 12.5 μg misoprostol sublingually and a vaginal placebo, while the other group received a sublingual placebo and 25 μg misoprostol vaginally. The primary outcome was the frequency of tachysystole. Student's t-test, the chi-square test of association and Fisher's exact test were used, as appropriate. Risk ratios and their 95% confidence intervals were calculated. Results: The frequency of tachysystole was lower in the group using 12.5 μg misoprostol sublingually compared to the group using 25 μg misoprostol vaginally (RR = 0.15; 95%CI: 0.02-0.97; p = 0.002). Failure to achieve vaginal delivery within 12 and 24 h was similar in both groups. Sublingual administration was preferred to vaginal administration by women in both groups; however, the difference was not statistically significant. Conclusion: The effectiveness of labor induction with low-dose sublingual misoprostol was similar to that achieved with vaginal administration of the recommended dose; however, the rate of tachysystole was lower in the sublingual group, and this route of administration may prove a safe alternative.

Cervical Versus Vaginal, and Sublingual Misoprostol for Labor Induction at Term Parturient: a Randomized Double-blind Clinical Trial

“…It is also possible to display intracervical and sublingual administration as a more effective route than vaginal agents. Gattás's study_ A randomized, placebo-controlled trial of 12.5 µg sublingual and 25 µg vaginal dose administration found that in the sublingual community, the duration between the rst dose of misoprostol and the onset of labor was shorter (26). Sublingual misoprostol was also found in the Ayati's study to be as successful as vaginal misoprostol for term labor induction.…”

Results of Induction of Labor with Prostaglandins E1 and E2 (The RIPE Study): A Real-World Data Analysis of Obstetrical Effectiveness and Clinical Outcomes of Pharmacological Induction of Labor with Vaginal Inserts

“…These data are consistent with previous studies. According to these studies, patients receiving a vaginal insert with Misoprostol more often required intrapartum analgesia with opioids [ 25 , 26 , 27 ]. However, due to the study design, these figures may be overestimated.…”

Labor induction with randomized comparison of cervical, oral and intravaginal misoprostol

“…It is also possible to display intracervical and sublingual administration as a more effective route than vaginal agents. Gattás’s study_ A randomized, placebo-controlled trial of 12.5μgm sublingual and 25μgm vaginal dose administration found that in the sublingual community, the duration between the first dose of misoprostol and the onset of labor was shorter [ 24 ]. Sublingual misoprostol was also found in Ayati’s study to be as successful as vaginal misoprostol for term labor induction.…”