Improved intravaginal controlled-release prostaglandin E₂ insert for cervical ripening at term

The purpose of this study was to determine if prostaglandin E₂ (PGE₂) in a controlled-release vaginal insert with retrieval system can produce cervical ripening at term. This was a multicenter, double blind, randomized, placebo-controlled study involving 206 patients with 102 receiving active agent. A successful outcome was defined as a change in Bishop score of ≥3, or a Bishop score of ≥6 at 12 h or delivery within 12 h of the insert placement. Analysis was by Fisher's exact test, Wilcoxon's two-sample rank-sum test, and Student's t-test where appropriate. One hundred ninety-three women completed the protocol. Initial Bishop scores were 2.6 ± 1.2 and 2.5 ± 1.4 in the PGE₂ and placebo groups, respectively. The incidence of cesarean delivery was identical in the two groups. Uterine hyperstimulation lasted 2-13 min in 5 PGE₂ patients (4.9%) with 1 patient requiring tocolysis. More patients in the PGE₂ group had a change in Bishop score of ≥3 (62% vs. 40%; P = 0.002), a Bishop score ≥6 after 12 h (46% vs. 34%; P = 0.11), and vaginal delivery within 12 h (6.5% vs. 1%; P = 0.055). Sixty-five percent of PGE₂ group patients had a successful outcome vs. 44% of control patients (P = 0.001). In conclusion, when administered in a controlled-release vaginal insert with a retrieval system, PGE₂ is effective in promoting cervical ripening at term.