Progesterone
Progesterone is a hormone that prepares and maintains the uterine lining for an embryo. In IVF it is given after egg retrieval or before a frozen transfer as injections, vaginal gels or pessaries, or tablets, and continued through the two-week wait and often into early pregnancy.
Progesterone is the hormone that makes the lining of the uterus ready to hold a pregnancy. In a natural cycle the ovary produces it after ovulation; in IVF the body often needs it supplemented, so it is given as an injection, a vaginal gel or pessary, or a tablet.
You usually start progesterone around the time of egg retrieval in a fresh cycle, or in the days before a frozen embryo transfer, and continue it through the two-week wait. If the cycle succeeds, many clinics keep you on it into the early weeks of pregnancy. The side effects (bloating, sore breasts, tiredness) can mimic early-pregnancy signs, which is one reason symptoms during the two-week wait cannot predict the result.
For the full guide, including the forms it comes in and what to keep in mind, see progesterone support explained.
Sources and further reading
- ESHRE: Ovarian stimulation guideline (2025). Luteal support.
Source links checked on 7 September 2026. This source check is separate from medical review.
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