Background Mifepristone, followed 48 hours later by administration of misoprostol, is a well-established regimen for medical termination of pregnancy (TOP). Although this regimen is effective, its inflexibility may limit its provision in an outpatient service.

Objective To confirm that misoprostol administration is effective whether administered 24, 48 or 72 hours after oral mifepristone.

Design Observational study of 234 consecutive women with pregnancies up to 83 days' gestational age in whom medical TOP was performed during the period December 2000-July 2001.

Setting Women's Health Care Department, Royal Bolton Hospital, Bolton, UK.

Results There was a high success rate for complete abortion in all groups whether mifepristone was administered 24, 48 or 72 hours prior to misoprostol.

Conclusion This study suggests that a more flexible regimen of mifepristone/misoprostol administration for medical TOP is effective in routine clinical practice.