Background: Cervical preparation before second-trimester dilation and evacuation reduces surgical risk. Same-day cervical preparation in early second trimester is safe and effective with osmotic cervical dilators and prostaglandin analogues but few studies have examined cervical preparation methods for same-day dilation and evacuation in the second trimester. Administration of misoprostol as an adjunct to osmotic dilators prior to same-day second trimester dilation and evacuation dilation and evacuation has the potential to improve cervical dilation.
Objective: To investigate the efficacy of buccal misoprostol compared to placebo as an adjunct to Dilapan-S for cervical preparation prior to same-day second trimester dilation and evacuation.
Methods: In this randomized, double-blinded, placebo-controlled trial, participants 16 to 20+6 weeks gestation received synthetic osmotic dilators (Dilapan-S) and were randomized to 400 micrograms of buccal misoprostol or placebo at least 3 hours before same-day dilation and evacuation. Randomization was stratified by gestational age and enrollment site. The primary outcome was operative time with a sample size of 36 needed to detect a 4 minute difference (two-sided [alpha]=0.05, 80% power). Secondary outcomes, including patient perception of pain with cervical preparation, side effects and acceptability, baseline cervical dilation, ease of further mechanical dilation, complications and provider assessment of difficulty were also assessed.
Results: Twenty-nine of thirty-six women have been randomized. Average gestational age was 19+0 weeks. Thirty-eight percent of patients were primigravid. Mean operative time was 12.34 minutes (SD+4.76 min) and mean baseline dilation was 54.79 mm (SD+13.27 mm). All participants had their dilation and evacuation completed on the same day without additional cervical preparation. Additional mechanical dilation was performed in 79% of procedures. Clinicians reported satisfaction with cervical preparation in two-thirds of the cases and easy mechanical dilation in 70% of cases. The overall complication rate was 17% (2 major, 3 minor) and enrollment in the upper gestational age stratum was closed for safety. The majority of participants (86%) were satisfied with their cervical preparation method and 97% reported preferring a same-day regimen.
Conclusion: The addition of buccal misoprostol to synthetic osmotic dilators for cervical preparation may reduce operative time and increase ease of mechanical cervical dilation for same-day dilation and evacuation later in the second trimester. The complication rate in this study was higher than anticipated, particularly in upper gestational ages included, which may be due to inadequate cervical preparation. Since patients prefer same-day cervical preparation, further studies are needed to identify safe and effective cervical preparation methods for same-day dilation and evacuation.