A randomized controlled trial to compare concurrent use of vaginal misoprostol and transcervical foley catheter inflated with 60 mL vs 80 mL in nulliparous pregnant women at term for induction of labor

Induction of labor (IOL) implies stimulation of uterine contractions before the spontaneous onset of labor, with or without ruptured membranes.1 It is an intervention designed for iatrogenic ripening of cervix and to initiate uterine contractions leading to progressive dilatation and effacement of cervix resulting in birth of the newborn. The goal of IOL is to achieve a successful vaginal delivery with minimal maternal and fetal complications. Cervical ripening is an important factor for a successful IOL. Unripe cervix with a lower Bishop score is associated with an increased risk of failure of IOL, while a favorable cervix signiï¬cantly predicts a timely delivery. There are two main methods of cervical ripening. One is mechanical, including (1) the introduction of a catheter through the cervix into the extra-amniotic space with balloon insufflation; (2) introduction of laminaria tents, or their synthetic equivalent, into the cervical canal; (3) use of a catheter to inject fluid into the extra-amniotic space. Transcervical foley’s catheter (TCFC) is cheap, easy to use, readily available, relatively painless and reversible method for IOL. The other method is pharmacological. Pharmacological methods include many agents, such as prostaglandins (PG) such as misoprostol i.e. PGE1 and dinoprostone i.e. PGE2 , progesterone receptor antagonists (mifepristone), oxytocin, and nitric oxide (NO) donors, but the most commonly used are prostaglandins and oxytocin. although the best agent and method for IOL remains uncertain, it is biologically plausible that a combination of a mechanical device (TCFC) and mechanical agent (misoprostol) may have a synergistic effect, resulting in a greater degree of cervical ripening and shorter induction to delivery time with concomitant reduction of side effects of each.In an attempt to raise the bishop score at a faster rate and decrease the time to delivery, TCFC are often overinflated or TCFC that accept larger volumes are used.13 The likelihood of vaginal delivery is correlated with a higher Bishop score at the time of induction, hence it is postulated that a higher volume TCFC used for cervical ripening will be associated with a higher bishop score which will further lead to higher rate of vaginal delivery.14

Hence, we plan to compare variable volumes of inflation of TCFC as an adjunct for IOL in pregnant nulliparous women at term.