Menstrual cycle & ovulation
The follicular phase runs from the start of a period to ovulation. FSH stimulates follicles to grow and oestradiol levels rise. Its length varies more than the luteal phase, which is why cycle lengths differ.
Sources
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.