Local application of its gel form-Prepidil-is available in a 2.5-mL syringe for an intracervical application of 0.5 mg of dinoprostone. With the woman supine, the tip of a prefilled syringe is placed intracervically, and the gel is deposited just below the internal cervical os. After application, the woman remains reclined for at least 30 minutes. Doses may be repeated every 6 hours, with a maximum of three doses recommended in 24 hours.
A 10-mg dinoprostone vaginal insert-Cervidil-is also approved for cervical ripening. This is a thin, flat, rectangular polymeric wafer held within a small, white, mesh polyester sac (Fig. 26-
The sac has a long attached tail to allow easy removal from the vagina. The insert provides slower release of medication-0.3 mg/hr-than the gel form. Cervidil is used as a single dose placed transversely in the posterior vaginal fornix. Lubricant is used sparingly, if at all, because it can coat the device and hinder dinoprostone release. Following insertion, the woman remains recumbent for at least 2 hours. he insert is removed after 12 hours or with labor onset and at least 30 minutes before the administration of oxytocin.
FIGURE 26-1 Cervidil vaginal insert contains 10 mg of dinoprostone designed to release approximately OJ mg/hr during a1 O-hour period.
Most metaanalyses of dinoprostone eicacy report a reduced time-to-delivery within 24 hours, however, they do not consistently show a reduction in the cesarean delivery rate. Thomas and colleagues (2014) provided a Cochrane review of 70 trials and 11i,487 women given vaginal prostaglandins or either placebo or no treatment. They noted a higher vaginal delivery rate within 24 hours when prostaglandins were used. hey also reported a threefold greater risk of tachysystole accompanied by fetal heart rate changes, but cesarean delivery rates were not signiicantly decreased. Similar results were noted in another Cochrane review of intracervical dinoprostone gel (Boulvain, 2008). Compared with placebo or no treatment, a reduced risk of cesarean delivery was found only in a subgroup of women with an unfavorable cervix and intact membranes. Finally, the Foley catheter versus vaginal PGE2 gel for induction of labor at term-PROBAAT-P and -M trials-were un blinded, randomized trials comparing these two options Qozwiak, 2011, 2013, 2014). he cesarean delivery rate did not difer, a inding consistent with accompanying metaanalyses.
Side Efects. Uterine tachysystole follows vaginally administered PGE2 in 1 to 5 percent of women (Hawkins, 2012). Although deinitions of abnormal uterine activity vary among studies, most use the definition recommended by the American College of Obstetricians and Gynecologists (2017a): 1.
Uterine tachysystole is deined as > 5 contractions in a 10-minute period. It should always be qualiied by the presence or absence of fetal heart rate abnormalities.
2.
Uterine hypertonus, hyperstimulation, and hypercontractiliy are terms no longer deined, and their use is not recommended.
Because uterine tachysystole associated with fetal compromise may develop when prostaglandins are used with preexisting spontaneous labor, such use is not recommended. If tachysystole follows the 10-mg insert, its removal by pulling on the tail of the surrounding net sac will usually reverse this efect. Irrigation to remove the gel preparation has not been shown to be helpful.