Adjuvant misoprostol or mifepristone for cervical preparation with osmotic dilators before dilation and evacuation.

OBJECTIVE: To compare effectiveness and safety of cervical preparation with osmotic dilators plus same-day misoprostol or overnight mifepristone prior to dilation and evacuation (D&E).

STUDY DESIGN: We conducted a retrospective cohort analysis of 664 patients initiating abortion between 18 and 22 weeks at an ambulatory health center. We abstracted medical record data from two consecutive 12-month periods in 2017 to 2019. All patients received overnight dilators plus: 600 mcg buccal misoprostol 90 minutes before D&E (period 1); 200 mg oral mifepristone at time of dilators (period 2). Our primary outcome was procedure time. We needed 104 patients for 80% power to detect a 2.5-minute difference. We included all available patient data during both time periods in this convenience sample to compare secondary safety outcomes. We report frequency of patients experiencing any acute complication, defined as an unplanned procedure (i.e. reaspiration, cervical laceration repair, uterine balloon tamponade) or hospital transfer, and bleeding complications.

RESULTS: We observed higher mean procedure time in the mifepristone group (9.7±5.3 minutes versus 7.9±4.4, p=0.004). After adjusting for race, ethnicity, insurance, BMI, parity, prior cesarean, prior uterine surgery, gestational age, provider, trainee participation, and LARC initiation, the difference remained statistically significant (relative change 1.09, 95% CI (1.01, 1.17)), but failed to reach our threshold for clinical significance. Use of additional misoprostol was more common in the mifepristone group, but use of an additional set of dilators was not different between groups. Acute complications occurred at a frequency of 4.1% in misoprostol group and 4.3% in mifepristone group (p=0.90).

CONCLUSIONS: We found procedure time to be longer with adjunctive mifepristone compared to misoprostol; however, this difference is unlikely to be clinically meaningful. Further, the frequency of acute complications was similar between groups.

IMPLICATIONS: Overnight mifepristone at the time of cervical dilator placement is a safe and effective alternative to adjuvant same-day misoprostol for cervical preparation prior to D&E and may offer benefits for clinic flow and patient experience.