As well as using a diary method to learn about your menstrual cycle, some women find it useful to notice the way that their cervical fluid changes. The cervix secretes mucus throughout the menstrual cycle, but the mucus changes at different points in the cycle.

Around ovulation, it increases and becomes much thinner, slippery and stretchy. If you were to put some mucus between your finger and thumb, you would find that it would stretch several centimetres. It is often compared to raw egg white. This mucus is designed to help the sperm swim easily through it and nourish it. This is a good indicator that you are in your fertile phase.

This is the time to have sex if you want to get pregnant, or to use contraception if you do not! A few days after ovulation, the mucus changes again. This time there is less of it and it is thick and cloudy. In this state it is hostile to sperm.