Predictors of analgesia use during supervised medical abortion. The Mifepristone Clinical Trials Group.

The object of this analysis was to identify predictors of narcotic analgesic use during medical abortion. A total of 2121 women with pregnancies of </=63 days gestational age received 600 mg mifepristone followed 48 h later by 400 microg oral misoprostol in a single arm clinical trial perfomed at 17 centers in the US. We tested the effects of subject characteristics at baseline and study centers on the use of any narcotic analgesics on the day of misoprostol use. Overall, 27% of subjects received narcotic analgesics. The main determinant of narcotic analgesic use was the study center. The relative risk of using narcotic analgesics increased with gestational age; the relative risk decreased in women with previous births, and also decreased with increasing age of the woman receiving treatment. It is concluded use of narcotic analgesia during medical abortion is least likely among older, parous women at low gestational ages; however, the clinic providing care for the patient was the most important determinant of who received narcotic analgesia.