Comparison of digital and speculum-guided methods of transcervical Foley catheter insertion in primigravida undergoing cervical ripening at term gestation: a noninferiority randomized clinical trial

Abstract

BackgroundFoley catheter insertion is frequently utilized for cervical ripening during the induction of labour. However, the insertion failure, safety, maternal side effects, complications and satisfaction of digital compared to speculum-guided Foley catheter placement have not been evaluated in a large trial involving primigravida. ObjectivesThe study aimed to compare the insertion failure rate of digital and speculum-based transcervical Foley catheter placement in primigravida. The co-primary outcome was insertion-associated pain. The secondary outcomes were time required for successful insertion, maternal satisfaction, and maternal complications within 24 hours of Foley insertion. MethodsThis randomized, open-label, parallel-arm, non-inferiority clinical trial was performed in a large tertiary care university hospital. Primigravida >18 years of age with term gestation (≥37 weeks) were included in this study. Additional inclusion criteria for enrolment in this study were singleton pregnancy with a cephalic presentation, intact membrane, Bishop score ≤5 and reassuring pre-induction foetal heart rate tracing. All women planned for cervical ripening were assessed for eligibility and were randomized into digital or speculum arms. Foley catheter insertion was performed in a supine lithotomy position. Vaginal and cervical cleaning were performed before insertion. A 22-French Foley balloon catheter was guided digitally or via speculum to position the bulb at the level of the internal os using water-soluble lubricant. Insertion-associated pain was measured using visual numeric rating scale (VNRS) and maternal satisfaction was assessed using a set of questions. Results469 pregnant women were assessed for eligibility, and 446 patients were enrolled and randomized. The median age of the parturients was 24 (19-40) and 24 (18-38) years, respectively. The body mass index, gestational age at randomization, incidence of post-dated pregnancy and pre-randomization Bishop scores were comparable. Insertion failure was observed in 24 (10.8%) and 17 (7.6%) of women in digital and speculum arm, respectively (RR= 1.41; 95% CI, 0.78-2.55; P=0.25). Requirements of more than one attempt (5.4% vs 3.6%) followed by change in hands (3.6% vs 2.7%) were the most common reasons for insertion failure. The median (interquartile range) VNRS was comparable (6.00 (2-9) vs 5.00 (2-10); p=0.15). The time taken for successful insertion was similar (58 (12-241) vs 54 (10-281); p=0.30). 9.4% and 10.8% of women required additional methods of cervical ripening. More women in the speculum group (41.7% vs 33.2%; P=0.06) felt a medium level of discomfort than digital group. ConclusionInsertion failure and insertion-related pain in the digital approach were comparable to the speculum-guided approach for transcervical Foley catheter insertion in primigravida for cervical ripening. Nevertheless, maternal satisfaction was higher in the digital group due to a lesser level of discomfort.