Oral misoprostol shows shorter induction delivery interval compared to vaginal misoprostol: study
Induction of labour is the artificial initiation of labour before the spontaneous onset, and it is the common obstetric intervention. The ultimate aim of labour induction is uterine contraction stimulation before spontaneous onset resulting in vaginal delivery.
Misoprostol is unique prostaglandin E1 analog. Misoprostol can be administered by various oral, buccal, sublingual, rectal, and vaginal routes. Misoprostol is available at low cost, stable at room temperature, and easy availability of the drug.
The oral route of misoprostol solution is better tolerated by women as it involves less vaginal examination. Vaginal administration of 25 micrograms of misoprostol is considered safe with fewer uterine tachysystole rates, uterine hyperstimulation, and cesarean section due to meconium.
A study was conducted at Government general hospital, Kakinada, from July 2020 to September 2020 by Lavanyakumari Sarella and Vijayalakshmi Uthrakumar and was published in Indian Journal of Obstetrics and Gynecology Research comparing induction of labour with oral misoprostol solution 20 microgram versus vaginal misoprostol 25 microgram 6th hourly.
80 women requiring induction were recruited in the study. The women were randomized to receive 20 micrograms of oral misoprostol solution every 2nd hourly or vaginally 25 micrograms of misoprostol every 6t h hourly until the labour sets in the active phase of labour. Delivery within 24 hours was the outcome in the study.
In the oral misoprostol solution group,
- 87.5% delivered vaginally within 24 hours and 12.5% delivered by cesarean section;
- 75% of patients do not require oxytocin to augment labour; 25% required oxytocin augmentation
- 22.5% had a bishop score of 0- 2, 37.5% had a bishop score of 3-4, 40% had a bishop score of 5
- 12.5% had meconium stained liquor, 2.5% had meconium aspiration syndrome, Apgar <=7 at 1min of 10%, 5% had NICU admission of duration < 5 days.
In the per-vaginal group,
- 90% delivered vaginally within 24 hours and 10% delivered by cesarean section
- 57.5% required oxytocin augmentation, 42.5% does not require oxytocin to augment labor
- 22.5% had bishop score of 0-2, 27.5% had bishop score of 3-4, 50% had bishop score of 5. (P-value <0.001).
- 20% had meconium stained liquor, 7.5% had meconium aspiration syndrome, Apgar <=7 at 1min of 10%, Apgar <=7 at 5min of 2.5%, 12.5% had NICU admission of duration < 5 days.
The mean birth weight in each group is 3 kg.
In both groups, there was no severe side effect. In the oral misoprostol group, 7.5% had nausea, and in per vaginal group, 12.5% had fever. In the oral misoprostol group, the number of per vaginal examination is reduced, making the patient comfortable.
Low dose misoprostol solution for the induction of labour was found equally effective in achieving vaginal delivery within 24 hours as compared to per vaginal group with less cesarean rate and less need of oxytocin augmentation, less fetal distress with good safety to the mother in this study.
Low dose misoprostol induces low-frequency contraction and decreases the myometrial acidaemia. The oral solution gives dose accuracy and patient satisfaction positively as reported. Compared to per vaginal group, 42.5% required oxytocin, only 25% required oxytocin augmentation in the oral misoprostol group. Safety is associated with the rapid clearance of the drug in oral misoprostol.
The study concluded , "Misoprostol is used as a promising agent in labour induction after being approved by the FDA. Misoprostol is costeffective, readily available, and cheap, and stable at room temperature can be safely used in developing countries. It has an excellent uterotonic and cervical ripening effect in both groups. Low bishop score requires oxytocin augmentation and increased cesarean rate in misoprostol in both groups. Compared with vaginal misoprostol, oral misoprostol solution results in a shorter induction delivery interval and less oxytocin augmentation required."
Source: Sarella and Uthrakumar / Indian Journal of Obstetrics and Gynecology Research 2021;8(1):95–99