Fertility awareness based methods for pregnancy prevention

### What you need to know Fertility awareness based methods of contraception are increasingly being used for pregnancy prevention.1 In the US, the proportion of contraceptive users who choose such methods has grown from 1% in 2008 to approximately 3% in 2014.12 Relative to other methods of pregnancy prevention, however, substantial misinformation exists around fertility awareness based methods of contraception, particularly about the effectiveness of specific methods and how to use them. Providers who offer family planning counselling can promote correct and consistent use of the chosen method by helping people find a method that best fits their individual lifestyle, preferences, and goals.3 This article aims to help clinicians counsel people about fertility awareness based methods for pregnancy prevention by explaining the different methods, the evidence base for their effectiveness, and practical considerations for use. Fertility awareness based methods are devised on the premise that sexual intercourse can only lead to pregnancy during approximately 6-9 days of the menstrual cycle, commonly referred to as the “fertile window” (or fecund window, box 1).5 …