A European review of available studies on the relationship between increasing body weight or BMI and efficacy of emergency contraceptives considered the data to be inconclusive. The overall conclusion was that emergency contraceptives are suitable for all women regardless of body weight or BMI. They should be used as soon as possible after unprotected sex or contraceptive failure to prevent unintended pregnancy. Further information and advice is available in a Drug Safety Update article from the MHRA (see link below).