Cervical mucus

Cervical mucus changes across the cycle under the influence of oestrogen. Around ovulation it typically becomes clearer, wetter and stretchy, similar to raw egg white, which helps sperm travel and survive. After ovulation progesterone makes it thicker and less penetrable. Observing this change is a free, practical way to identify the fertile window.

Also known as: egg white mucus, discharge, CM

Last reviewed: 8 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.