A comparison of the efficacy and safety of repetitive hourly dose of oral misoprostol and two hourly dose oral regimens for cervical ripening and labor induction: A R.C.T

Abstract

Induction of labor (IOL) is defined as artificial stimulation of uterine contractions before the spontaneous onset of labor, with or without ruptured membranes, Labor induction most frequently conducted through interventional procedures, and their use has been increasing in the past several decades. In a survey by the National Center for Health Statistics the rate of labor induction was noted to have increased from 9.5% in 1991 to 22.5% in 2006. Methods for induction of labor can be mechanical or pharmacological. Mechanical means of labor induction include the use of various types of catheters and hygroscopic dilators introduced into the cervical canal or into the extra amniotic space. Pharmacological methods include prostaglandins, mifepristone and oxytocin. Two types of prostaglandin preparations, natural prostaglandin E2 (dinoprostone) and synthetic prostaglandin E1 (misoprostol), are currently approved by the US Food and Drug Administration for pre-induction cervical ripening. Dinoprostone although widely used, has two disadvantages: it is expensive and requires continuous refrigeration. Misoprostol, therefore, which is less expensive and more stable at room temperature, has been proposed as an alternative agent for labor induction. However, misoprostol may lead to adverse effects such as gastrointestinal disturbance, uterine tachysystole, and the most severe, uterine rupture. These adverse effects are likely to be dose and route related. The more frequent dosing may address the short half-life of misoprostol, which is reported to reach the highest serum peak concentration (300- 800 pg./mL) in approximately 14-30 minutes, with a terminal half-life of 20- 40 minutes.