Amenorrhea Rates with Continuous Oral 17β-Estradiol and Micronized Progesterone

Clinical Implications and Dosing Strategy

The American College of Obstetricians and Gynecologists recommends starting with 17β-estradiol 1-2 mg orally daily plus micronized progesterone 100 mg daily continuously for women seeking to avoid withdrawal bleeding 1, 2, 3
For optimal amenorrhea rates, the Endocrine Society suggests combining transdermal estradiol patches (50-100 μg/day) with oral micronized progesterone 100-200 mg daily continuously 4, 5
Continuous dosing (every day without breaks) is the key to achieving amenorrhea, as opposed to sequential regimens that intentionally induce withdrawal bleeding, according to the American College of Obstetricians and Gynecologists 1, 2, 3

Baseline endometrial ultrasound is recommended before initiating therapy to document endometrial thickness, as advised by the Society of Obstetricians and Gynaecologists of Canada 4
If breakthrough bleeding persists beyond 6 months, endometrial assessment is warranted rather than automatic dose adjustment, according to the American College of Obstetricians and Gynecologists 6
The 100 mg daily continuous dose provides full endometrial protection long-term, whereas sequential regimens may have insufficient protection, as stated by the Endocrine Society 4

Combined transdermal patches with 17β-estradiol and levonorgestrel administered continuously (without interruptions) also achieve high amenorrhea rates, according to the European Society of Contraception and Reproductive Health 1, 2, 3
Example: patches releasing 50 μg of 17β-estradiol and 7 μg of levonorgestrel daily applied continuously, as recommended by the American College of Obstetricians and Gynecologists 1, 2, 3