There is a theoretical concern that women with a short menstrual cycle may ovulate very early in their cycle, putting them at risk of pregnancy if starting contraception as late as Day 5 or Day 7 (LNG-IUS). There is no strong evidence to support or refute the risk but some sources of patient information (. FPA) advise additional contraception for women in this situation if they have a cycle shorter than 23 days. Faculty guidance on postnatal sexual and reproductive health includes recommendations on starting contraceptive methods after Advice on starting methods after miscarriage or abortion and on switching from one contraceptive method to another can.
