A randomized controlled trial of fentanyl for abortion pain

Our aim was to find out whether intravenous fentanyl was effective in reducing the pain of first-trimester abortion.

This randomized controlled trial included 825 women attending a nonhospital abortion facility. Some women chose standard care. Women who did not choose standard care were randomly assigned to receive either 50 to 100 microg of fentanyl, a placebo, or no intervention. With SAS software and a mixed effects analysis of variance model with covariates, we compared mean pain scores of the fentanyl and placebo groups to detect a difference of at least 1 point on an 11-point pain scale.

The mean pain score of the fentanyl group was 1.0 point less than that of the placebo group (95% confidence interval, 3.7-4.3) and 0.9 point less than that of the observational group (95% confidence interval, 4.7-5.1). This pain reduction was statistically significant, but the women who were studied wanted a 2-point reduction from fentanyl.

Fentanyl, when compared with the placebo, reduced abortion pain by 1.0 point on an 11-point scale. This reduction was of questionable clinical significance and was less than desired by the women included in the study.