Abstract

Labor induction is used in approximately 20% of pregnancies in Europe and North America. Prostaglandins and prostaglandin analogs are favored when women undergoing labor induction have an unripe cervix. Controlled-release dinoprostone, delivered over 24 h from a vaginal insert, results in cervical ripening within 12 h in most women. It is marginally more effective than immediate release formulations and has similar efficacy to misoprostol, a prostaglandin E₁ analog used off-label for this indication. The controlled-release preparation offers many advantages compared with an immediate-release formulation: a single application is sufficient; it is less invasive; it is easily administered and removed, allowing greater dose control. The most significant adverse effect, uterine hyperstimulation, with and without an effect on fetal heart rate, occurs in 5–15% of patients, which is comparable with other formulations or misoprostol. The insert can be removed easily on the first sign of uterine hyperstimulation, or as soon as labor starts. The efficacy and safety of controlled-release dinoprostone are comparable whether it is used in the outpatient or the inpatient setting. For low-risk women, outpatient use may be a highly attractive option, potentially reducing hospital costs, and improving patient convenience. The ease of use of controlled-release dinoprostone and women's satisfaction emphasize its benefits over many other agents used to ripen the cervix.