Currently, no oral birth control method is approved for using only when needed, i.e., at the time of sex. However, many women may want to use such a method. Our review looked at studies of different drugs taken around the sex act to find out how well the drugs worked to prevent pregnancy. We also assessed the safety of the drugs and whether women liked them.
In October 2011, we did computer searches to find relevant studies in all languages. For the initial review, we also wrote to researchers to find other trials. We assessed the quality of the research methods used in the studies. We entered the data into RevMan. The data were entered into RevMan and the Pearl Index was used to estimate effect.
We found 21 studies conducted over the past 40 years. These studies found that using some hormones right before or after sex did prevent pregnancy. In particular, levonorgestrel seemed to work well and was safe and accepted by thousands of women in several large trials. However, most of the studies were old and incomplete. More high quality research is needed before we can know for sure whether using levonorgestrel repeatedly around the time of sex is a good and safe method of birth control.