Cervical Preparation Before Dilation and Evacuation Using Adjunctive Misoprostol or Mifepristone Compared With Overnight Osmotic Dilators Alone: A Randomized Controlled Trial

Obstet Gynecol; 2015 Sep; 126(3):599-609; doi:10.1097/AOG.0000000000000977

Objective: To evaluate operative time after adjunctive misoprostol or mifepristone compared with overnight osmotic dilators alone for cervical preparation before dilation and evacuation at 16-23 6/7 weeks of gestation.

Methods: This double-blind, three-arm, multicenter, randomized trial compared overnight osmotic dilators alone, dilators plus 400 micrograms buccal misoprostol 3 hours preoperatively, and dilators plus 200 mg oral mifepristone during dilator placement for dilation and evacuation. Our primary outcome was dilation and evacuation operative time within two cohorts: 16-18 6/7 weeks of gestation (N=150) and 19-23 6/7 weeks of gestation (N=150). Three hundred women were required for 80% power to detect a 2-minute difference in operative time. Secondary outcomes included initial cervical dilation, side effects, physician satisfaction by Likert scale, and complications.

Results: Between February 2013 and February 2014 we randomized 300 women evenly across treatment arms. Group demographics were similar. We found no difference in operative time in either gestational cohort (early cohort [minutes]: 5.11±3.0 dilators alone, 4.99±3.3 misoprostol, 4.33±2.0 mifepristone, P=.34; late cohort [minutes]: 7.50±3.7 dilators alone, 7.62±5.4 misoprostol, 6.74±3.2 mifepristone, P=.53). In the early cohort, initial dilation was greater with misoprostol than dilators alone (2.4 compared with 2.0 cm, P=.007). Patients given misoprostol had significantly more pain, fever, and chills. In the late cohort, dilation and evacuation procedures were less difficult after mifepristone (4.1%, 95% confidence interval [CI] 0.0-9.6) than misoprostol (18.8%, 95% CI 7.7-29.8) or dilators alone (18.8%, 95% CI 7.7-29.8; P=.04). We had inadequate power to infer differences in complications: dilators alone (10%, 95% CI 4.2-16.0) compared with misoprostol (2%, 95% CI 0-4.7) compared with mifepristone (2%, 95% CI 0-4.8).

Conclusion: Despite no difference in operative time, adjunctive mifepristone facilitates later dilation and evacuation compared with osmotic dilators alone and is better tolerated than misoprostol.