Why is micronised progesterone used in hormone replacement therapy?

Oestrogen can stimulate the lining of the uterus. Progesterone counterbalances that stimulation and helps reduce the risk of excessive lining growth. Some HRT plans use progesterone for part of each treatment cycle, while others use it continuously; the choice depends on symptoms, bleeding pattern, time since periods and medical history. It can cause sleepiness, breast tenderness, mood changes or bleeding, especially while the body adjusts.

Take the prescribed preparation as directed and do not alter the schedule because bleeding changes. Tell your clinician if you have unexplained vaginal bleeding, liver disease, previous hormone-related clots or breast symptoms. Keep follow-up appointments so troublesome bleeding or side effects can be reviewed and the regimen adjusted safely.

Arrange prompt medical review for new, persistent or heavy vaginal bleeding after the expected adjustment period, or bleeding after a long interval without periods. Seek emergency help for chest pain, sudden breathlessness, coughing blood, a painful swollen leg, severe headache or new weakness.

Ask whether you need progesterone, which schedule fits your treatment, how to manage drowsiness or bleeding, and when the uterine lining should be reviewed. See [Micronised Progesterone](/materials/micronised-progesterone/) and [Hormone Replacement Therapy](/treatments/menopause-and-hormone-therapy/hormone-replacement-therapy/).