From the Guidelines
For menopausal hormone therapy (MHT), a cyclic progestogen regimen is recommended as the first choice, with micronized progesterone (MP) being the preferred progestin, due to its association with a lower risk of cardiovascular disease and venous thromboembolism, as well as endometrial protection, as reported in recent studies 33. When considering MHT, the choice between cyclic and daily progestogen regimens depends on various factors, including the patient's preferences, medical history, and menopausal status.
- Cyclic regimens involve taking progestogen, such as MP, for 12-14 days every 28 days, alongside daily estrogen, resulting in monthly withdrawal bleeding.
- Continuous regimens involve taking lower doses of progestogen daily with estrogen, typically eliminating monthly bleeding after an initial adjustment period. The primary purpose of progestogen in MHT is to protect the endometrium from estrogen-stimulated hyperplasia and cancer risk, which both regimens accomplish effectively when used correctly 1. It is essential to note that progestins with anti-androgenic effects, such as medroxyprogesterone acetate (MPA) and norethisterone, should be avoided in patients with iatrogenic premature ovarian insufficiency (POI) due to their potential to worsen hypoandrogenism 1. In post-pubertal adolescent/young adult childhood cancer survivors with POI, combined 17βE and progestin patches are recommended as a first choice, with MP being the preferred progestin, due to its favorable safety profile and effectiveness in reducing the risk of cardiovascular disease and venous thromboembolism 1.
From the FDA Drug Label
When estrogen is prescribed for a postmenopausal woman with a uterus, a progestin should also be initiated to reduce the risk of endometrial cancer. Administration should be cyclic (e.g., 3 weeks on and 1 week off).
The choice between cyclic and daily progestogen therapy is not directly addressed in terms of a comparison, but cyclic administration is mentioned as an example of how estrogen and likely progestogen (by implication for uterine protection) should be given.
- The lowest effective dose and shortest duration are recommended.
- Cyclic administration (e.g., 3 weeks on and 1 week off) is specified for the treatment of moderate to severe vasomotor symptoms, vulval and vaginal atrophy associated with the menopause. 2
From the Research
Cyclic vs Daily Progesterone MHT
- The choice between cyclic and daily progesterone in menopausal hormone therapy (MHT) depends on various factors, including the risk of endometrial hyperplasia and the individual's symptoms and medical history 3, 4.
- Cyclic progesterone regimens involve taking progesterone for a certain number of days each month, while daily regimens involve taking a constant dose of progesterone every day 5.
- Studies have shown that both cyclic and daily progesterone regimens can provide effective endometrial protection, but the risk of endometrial hyperplasia may be lower with daily regimens 4.
- The type and dose of progesterone used can also affect the risk of endometrial hyperplasia, with some studies suggesting that lower doses of progesterone may be sufficient for endometrial protection 4, 6.
- Cyclic regimens may have advantages such as minimal progestin exposure, low rate of withdrawal bleeding, and lowered side effects, but may require more frequent progestin treatment and may result in cyclic bleeding or breast tenderness 5.
- Daily regimens, on the other hand, are simple and easy-to-use, and are designed to minimize bleeding, but may have a greater impact on lipoproteins and may increase the risk of certain side effects 5.
- Ultimately, the choice between cyclic and daily progesterone MHT should be individualized and based on a thorough discussion of the risks and benefits with a healthcare provider 7, 6.