Flexible mifepristone and misoprostol administration interval for first-trimester medical termination

The administration interval between mifepristone and misoprostol is usually about 36-48 h, which might affect a woman's choice of method of termination. Unwanted outcomes such as uterine bleeding, painful cramps and psychosocial issues which may occur during this long interval can be altered by a shorter administration interval. A shorter interval will be cost-effective as it saves both women's and clinician's time and other resources. If the waiting time interval between therapeutic interventions could be reduced without compromising efficacy, it will potentially improve compliance, patient acceptability and quality of care.

A systematic review of randomized controlled trials published from 1999 to 2008 was conducted to assess the evidence for a shorter mifepristone and misoprostol administration interval at first trimester medical termination. Searching strategy included MEDLINE, EMBASE, CLINAHL and Cochrane Library. The primary outcome measure was complete abortion without the need for a surgical procedure.

Five randomized controlled trials (RCT) compared the efficacy of mifepristone and misoprostol administration intervals between 0 and 72 h in 5139 participants. The complete abortion rates varied between 90% and 98%. Although the meta-analysis of pooled data of all RCTs shows no statistically significant difference in efficacy between the shorter and longer dosing intervals, there is a trend toward slightly lower success rates with administration intervals earlier than 8 h.

Overall efficacy of complete abortion is not statistically different between the longer and shorter administration intervals. This might encourage the clinician to adopt a 'flexible policy' with fully informed consent and consideration of all circumstances.