Menstrual cycle & ovulation
Progesterone causes a small, sustained rise in BBT after ovulation. Charting it only confirms ovulation afterwards, so it is not useful for timing sex, and NICE does not recommend it for predicting ovulation.
Also known as: BBT, temperature charting
Last reviewed: 23 September 2026. Written by the Antega Editorial Team. General information only — always follow the advice of your own clinic, doctor or pharmacist.