On demand contraception: Investigating efficacy of ulipristal acetate plus a COX-2 inhibitor at peak fertility
Awarded 2018
Complex Family Planning Fellowship Research
Erica Cahill, MD
Stanford University

Background:  Most unintended pregnancies occur in women who are not using regular contraception. Despite improvement in access to contraception, the percentage of sexually active women who are not using contraception has remained unchanged over the past ten years. One of the most common reasons cited for non-use is irregular intercourse. There is a significant interest in an oral on-demand – or only at the time of intercourse – pill, but no leading candidate.  Other studies have looked at emergency contraception pills for this purpose and have found that COX-2 inhibitors, a type of anti-inflammatory medication, may increase the efficacy.
Purpose: We wanted to evaluate a new combination of the most effective emergency contraception pill (ulipristal acetate) with the addition of a COX-2 inhibitor (meloxicam) to see if this would be the best option for an oral, on-demand contraceptive pill.
Methodology: We designed a trial based on prior studies looking at other medications. We enrolled 12 people ages 18-35 with regular ovulation who were not using hormonal contraception. We followed each participant for two menstrual cycles.  For the first “Control” cycle, we monitored her normal ovulation with ultrasound and lab tests.  For the second “Treatment” cycle, we gave her the study medications (ulipristal acetate and meloxicam) just before ovulation at peak fertility potential –  a timepoint previously defined by ultrasound criteria.  For each participant, we evaluated if we were able to disrupt their ovulation with the study medication in the second cycle and if so, in what ways.   We also collected information about changes in menstrual cycle length and side effects. 
Important Findings:  With this combination of study medications, we were able to disrupt ovulation in 90% of participants (8 of 9), suggesting that this medication combination may be the best candidate for people interested in an oral on-demand – or only at the time of intercourse – contraceptive pill. There were minimal side effects, but the menstrual cycle was on average 3 days longer in the treatment cycle.  We have not evaluated repeat doses of this medication combination yet.

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