Parity, initial dilatation predict misoprostol success: older gestational age is also a predictor. (Labor Induction).

ASHLAND, ORE.--Labor was successfully induced and a vaginal delivery completed within 24 hours in about half of 1,373 patients who received intravaginal misoprostol, primarily within six large, randomized, controlled clinical trials.

Records drawn from 7 years of study found that higher parity, greater initial cervical dilatation, and a slightly older estimated gestational age were all independent factors that predicted success using misoprostol for cervical ripening and labor induction, Dr. Deborah A. Wing said at the annual meeting of the Pacific Coast Obstetrical and Gynecological Society.

The analysis could help to predict which patients would be good candidates for induction with misoprostol, said Dr. Wing of the University of Southern California, Los Angeles.

Most of the patients included in Dr. Wing's analysis received 25 [micro]g of misoprostol at dosing intervals of 3-6 hours, with no more than 24 hours of administration of the drug permitted. A few patients included in an early trial received 50 [micro]g of intravaginal misoprostol at 3-hour intervals for a maximum of 24 hours.

All of the patients had a medical or obstetrical indication for induction. Most had an initial Bishop score of 4 or less, although 24 subjects had Bishop scores as high as 7. All had intact membranes and reassuring fetal status. No re-dosing was permitted if frequent uterine activity was detected, defined as more than three contractions in 10 minutes, or if the patient had adequate cervical ripening, defined as 80% effacement and dilatation of 3 cm.

"Once the woman progressed to 3 cm or so, we aggressively performed the amniotomy, and internal monitors were placed at the discretion of the managing physician. Oxytocin was given per a standardized infusion protocol, primarily for labor augmentation rather than induction," she said.

Successful induction ...