Objective: To compare the effectiveness and safety of two cervical ripening methods in term primiparous women with unfavorable cervices and oligohydramnios.
Methods: Women (126 cases) with oligohydramnios [amniotic fluid index (AFI) ≤5 cm] and a low Bishop Score (≤6) were assigned randomly to use double balloon catheter (mechanical method group, 67 cases) or dinoprostone 10 mg controlled-release vaginal insert (pharmacological method group, 59 cases) for induction of labor. The study's primary outcome was caesarean section rate (CSR). The secondary outcome measures included maternal and neonatal morbidity, an incremental changes in Bishop Score, and intrapartum interventions.
Results: There was no significant difference between the mechanical method group and the pharmacological method group in CSR and change in Bishop Score. Tacysystole, non-reassuring fetal heart patterns, and cases of newborn umbilical-cord arterial blood pH<7.1 were significantly lower with the mechanical method compared with the pharmacological method (p < 0.05). More patients needed additional intervention in the mechanical method group.
Conclusions: Both methods resulted in a similar CSR. Double balloon catheter resulted in fewer labor complications, but more frequent use of oxytocin and amniotomy. Compared with dinoprostone vaginal insert, double balloon catheter use may be less problematic in women with oligohydramnios.
Keywords: Cervical ripening; dinoprostone vaginal insert; double balloon catheter; induction of labor; oligohydramnios.