Dinoprostone vaginal insert better than oral Misoprostol in reducing induction to delivery interval

An ideal inducing agent is one which achieves labour in the shortest possible time, with a low incidence of operative delivery, cost effective, good shelf life, easily stored, does not affect the feto-placental unit, with no increase in maternal or perinatal morbidity.

Dinoprostone- PGE2 is currently available as a 10-mg sustained-release vaginal insert that releases dinoprostone at a rate of 0.3 mg/hour for 24 hours. The advantages of dinoprostone insert is that it is easy vaginal application and removed in the event of uterine hyperstimulation. But, PGE2 insert is more expensive and needs cold storage. Dinoprostone is administered intravaginally and its half-life is approximately 2.5-5 minutes.

Misoprostol is a synthetic prostaglandins (PGE1) analogue; it is rapidly absorbed by gastrointestinal tract. Misoprostol is extensively used because it is effective, inexpensive, available in tablet form, and no need cold storage. It has minimal effect on cardiovascular system and bronchial smooth muscles and so can be safely used in hypertensive and asthmatic patient.

Misoprostol can be administered intravaginally, orally, or sublingually and is used for both cervical ripening and induction of labor. Total systemic bioactivity of vaginal misoprostol is three times greater than that of orally administered misoprostol. The use of sublingual misoprostol also offers high efficacy as it bypasses gastrointestinal and hepatic metabolism and also lowers hyperstimulation of uterus.

Very limited knowledge is available on the efficacy of sublingual PGE1 and intravaginal controlled slow release PGE2 insert. A study was designed by Sahu and Janjewal to bridge this lacunae comparing effectiveness of sublingual PGE1 with intravaginal PGE2 insert for mean induction to delivery time, maternal and fetal outcome.

The aims of study were:

1. To compare the efficacy and induction to delivery interval (IDI) of PGE2 vaginal insert and Sublingual PGE1 in induction of labor in term pregnant women;

2. To study the maternal and fetal outcome in both groups. Materials and Methods: This a randomized, prospective, comparative study of 100 term pregnant women for induction of labour.

Group 1-(50 women) included PGE2-10 mg vaginal insert and group 2-(50 women) PE1 Sublingual tablets – maximum 200 mcg in 24 hrs, at Dr LH Hiranandani Hospital, Mumbai, India.

In this study the mean induction to delivery interval in Dinoprostone group was 17.47 hours and 23.44 hours in Misoprostol group. So the mean IDI was shorter in Dinoprostone insert group than Misoprostol group by about 6 hours. There was no significant difference noted in terms of overall incidence of caesarean deliveries among the groups.

The Bishop's score improved better in Dinoprostone group 1 than in Misoprostol group 2. In this study, in Dinoprostone insert group, 18 out of 50 (36%)cases needed oxytocin for augmentation. And in Misoprostol group, 28 out of 50 (56%) cases needed oxytocin for augmentation. So the Dinoprostone group required less oxytocin augmentation than the Misoprostol group.

The mean (S.D.) duration of active phase for Misoprostol group was 6.16hours(2.62) while for Dinoprostone group was 4.57hours (1.90). There was statistically significant difference in duration of active phase between the two Groups. P value less than 0.01. So in this study active phase of labour was shorter in Dinoprostone group.

There was no statistical significant difference in the Mean Birth weight of the babies, Apgar score and NICU across the two groups

In the study of 100 antenatal women, 50 participants were induced with Dinoprostone vaginal insert 10mg (PGE2) and 50 participants were induced with sublingual Misoprostol tablets (PGE1) maximum dose-200mcg in 24hours. There was no significant difference noted in terms of overall incidence of caesarean deliveries among the groups. The incidence of meconium stained amniotic fluid was less in Dinoprostone group thus reducing the maternal and fetal morbidity. Dinoprostone is comparatively expensive, requires refrigeration (-10 to -25C), and is not stable at room temperature. Thus authors came to a conclusion that Dinoprostone vaginal insert was more efficient than sublingual Misoprostol in terms of short induction to delivery interval without maternal and fetal complications.

Source: Sahu and Janjewal / Indian Journal of Obstetrics and Gynecology Research 2021;8(4):457–462

https://doi.org/10.18231/j.ijogr.2021.096