Emergency Contraception and BMI

The Women's Health Research Unit is conducting a study to e compare how well emergency contraceptive pill containing ulipristal acetate works in women of varying BMIs. 

Why is this study being done?

Currently, women have two different types of emergency contraceptive pills available to use, one containing levonorgestrel (LNG, otherwise known as Plan B©) and another containing ulipristal acetate (UPA, otherwise known as Ella©). Women of higher weight and BMI are more likely than women of lower weight and BMI to experience a failure of the emergency contraceptive containing LNG. It is unclear if this is also an issue for the emergency contraceptive containing UPA.

We are performing a study to confirm how well the emergency contraceptive containing UPA works for women of higher BMI and weights as well as testing a different dose amount. The overall goal of this research is to improve the effectiveness of emergency contraception for women, no matter their weight or BMI.  

The purpose of this study is:

  • To compare drug levels and ovarian activity between women of higher and lower BMIs with UPA-containing emergency contraception and to test a different dose of UPA-containing emergency contraception in women of higher BMI.


Women who are between the ages of 18-35 who:

  • Have normal menstrual cycles
  • Have both a BMI of 30 mg/kor higher and a weight of 176 lbs or more. 
  • Are willing to use non-hormonal contraception during the study such as a condom or other barrier method
  • Are not currently using a hormonal form of birth control

Even if you have a Copper-IUD or have had a Tubal Ligation, you may still qualify for this study. 


Study visits are timed with the start of a woman's menstrual cycle and are concentrated during a 2 week time period in the beginning to middle of each menstrual cycle with gaps of time in between where no study visits would occur. Study visits may occur on weekends or holidays depending on participant's menstrual cycle. Participation would last approximately 3 months and the number of visits would be approximately 25 visits. Participants may be compensated up to $1,520 for time and travel. 

Who do I contact for additional information?

To find out more information and to learn if you are qualified to participate, please call the Women's Health Research Unit's confidential recruitment line at 503-494-3666or email us at whru@ohsu.edu.