It is important to prevent pregnancy until you are ready for conception by using a method that does not affect your fertility. All hormonal contraception works by inhibiting the natural fertility cycle, while the time it takes for fertility to return to normal after stopping depends on the type you have been using.
The body usually recovers quite quickly from use of the combined oral contraceptive pill, progestogen-only pill, implants and the intrauterine device (IUD or coil) but it can still take several months or more before you become pregnant. However, if you have been having progestogen injections, it can take between 6 and 18 months for ovulation to return to normal. Barrier methods such as the condom or diaphragm and spermicides are medically safe and instantly reversible which makes them ideal for use during the preconception stage.
Natural family planning – or fertility awareness – is another good form of contraception during this time and it has the added advantage of helping you to understand your fertility pattern. But it is important to remember that it can take between 3 and 6 monthly cycles to learn your fertility pattern, so this method should be combined with a barrier method until you are confident about using it.
If your baby is not planned then there is a chance you may continue with your contraception for some weeks before realising you are pregnant.
Rarely, women can become pregnant when they have an IUD in place. If this happens there is a higher chance of the pregnancy being ectopic (when the fertilised egg implants outside the uterus, usually in a fallopian tube). It is recommended that the IUD should be removed before the pregnancy reaches 12 weeks. If the IUD is left in place during pregnancy the rate of miscarriage is 50-60% compared to 13% if it is removed. Once the device has been removed, and the pregnancy continues to full term, the baby is likely to be as normal as any other.