Progesterone and progestogens in HRT

If you take estrogen and still have a uterus, you also need a progestogen — progesterone itself, or a synthetic equivalent. NICE guideline NG23 recommends combined HRT specifically for this reason: the progestogen protects the uterine lining from the effects of estrogen taken alone, which can otherwise raise the risk of endometrial hyperplasia and cancer. See estrogen in HRT for the other half of this picture.

Sequential or continuous: two ways to take it

• Sequential combined HRT: The progestogen is included for only part of each cycle, which typically produces a regular, period-like bleed.
• Continuous combined HRT: The progestogen is included every day, aiming to avoid a regular bleed — usually used once you're further past menopause.

NICE recommends discussing both options when choosing combined HRT. See types of HRT for how this fits into the bigger picture.

Does the type of progestogen matter for breast cancer risk?

This is a genuinely open question right now. Different formulations exist — micronised progesterone, dydrogesterone, and other synthetic progestogens — and NICE guidance is explicit that there isn't yet enough evidence to say whether breast cancer risk with combined HRT differs between micronised progesterone or dydrogesterone and other progestogens. See our full HRT and breast cancer risk breakdown for the fuller picture, including what is established: sequential regimens carry a lower risk than continuous ones, though both carry more than no HRT at all.

What this means for you

The choice of progestogen and regimen is a conversation to have directly with your prescriber, factoring in your tolerance for bleeding, any history of breast cancer risk factors, and how each formulation has affected you if you've tried hormone therapy before. See our Does It Work? evidence directory if you're also weighing non-hormonal options.

Use our treatment conversation builder to prepare for this conversation: