Objectives: To test an algorithm for determining IV sedation dosing that takes individual factors into account during first trimester surgical abortion. Methods: We conducted a randomized, single-blinded, controlled trial, comparing pain scores in patients undergoing first trimester surgical abortion, who receive IV sedation according to standard practice or an algorithm that determines dose based on individual patient factors. The primary outcome was pain scores for uterine aspiration on a 21-point pain scale from 0-100, measured immediately after the procedure, as well as recalled in the recovery room. Secondary outcomes included pain scores with cervical dilation and post-procedure, subjective pain ratings, need for additional medication, side effects and adverse events, and patient and physician satisfaction. Results: One hundred and ninety-six subjects were enrolled. There were no significant baseline differences between groups. Preliminary analysis shows no significant differences in pain scores between groups for the primary outcomes. The median pain score for uterine aspiration as recorded immediately after the procedure was 47.5 [20, 75] for the Standard arm and 50 [25, 80] for the Algorithm arm (p=0.81). The median pain score for uterine aspiration as recalled by the patients in the recovery room also did not differ by group (30 [10, 50] vs. 30 [15, 45] p=0.068). Additional analyses are ongoing. Conclusions: IV sedation for surgical abortion administered by a personalized algorithm does not appear to result in lower pain scores than standard dosing. Additional analysis is ongoing to determine any other risks, benefits or advantages of using this dosing strategy.