Fertility awareness is a method that requires you to observe fertility signs and work out exactly what stage of your menstrual cycle you are in. You need to identify the stages at which you are not fertile, and having sex at those times. If fertility awareness interests you, you are advised to use a barrier method or abstain from sex altogether on the days you are fertile. If you wish to get pregnant, fertility awareness can help you to identify which days you should be having sex to achieve pregnancy.
Each technique is complex and relies on a deep and intimate knowledge of your own menstrual cycle. The techniques base themselves on the fact that there are specific days during each menstrual cycle, the days before and shortly after ovulation, where you can get pregnant and others where you cannot, which is where the intimate knowledge and the calculations come in. There are a number of different methods such as tracking the days of your cycle, paying attention to body temperature fluctuations and keeping a very close eye on changes to your cervical mucus. There are several more techniques but they can all be thrown by slight changes to your cycle, a miscalculation, spontaneous lifestyle resulting in non-regular sleeping time or a host of other variables.
Reference: http://www.fpa.org.uk/contraception-help/your-guide-contraception Accessed on September 6, 2016 (PP-YAZ-MY-0056-01(10/2018))
Can be used when breastfeeding
If you want to get pregnant, it can help you to know on which days you should have sex
Using it may take practice
Requires keeping track of your menstruation cycle constantly
Requires a very regular lifestyle
Can interfere with spontaneity
Unreliable as it does not take variations in your cycle into account
Does not protect against HIV infection (AIDS) and other sexually transmitted infections (STIs)