Progesterone

Progesterone is produced by the corpus luteum after ovulation, and later by the placenta. It changes the endometrium into a receptive state and helps maintain early pregnancy. Blood testing about seven days before the expected period is used to confirm ovulation, and progesterone medicines are widely used as luteal support after embryo transfer.

Also known as: P4, progesterone hormone

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.