Does 100mg Progesterone Suppress Periods on 50mcg Estradiol Patch?
No, 100 mg oral micronized progesterone daily does not reliably suppress menstrual bleeding when combined with a 50 mcg transdermal estradiol patch—this dose is intended for continuous combined regimens to induce amenorrhea, not for sequential regimens that produce withdrawal bleeding. 1
Understanding the Two Different Regimens
The confusion here stems from mixing two distinct hormone replacement therapy approaches:
Sequential Regimen (Produces Monthly Bleeding)
- Sequential HRT is designed to cause regular withdrawal bleeding, not suppress it 2
- The standard sequential approach uses transdermal 17β-estradiol 50-100 μg daily continuously combined with oral micronized progesterone 200 mg daily for 12-14 days per 28-day cycle 1, 2
- Withdrawal bleeding typically occurs during or shortly after the progesterone phase (days 15-28 of the cycle) 2
- This regimen results in 73.6% of cycles showing regular progestogen-related bleeding when using the correct 200 mg dose 3
Continuous Combined Regimen (Suppresses Bleeding)
- Continuous combined therapy aims to induce amenorrhea by giving both hormones daily without interruption 1
- For amenorrhea induction, the dose is 100 mg oral micronized progesterone daily for 21-25 days per month (not 12-14 days) combined with continuous estradiol 4
- This approach achieved 91.6% amenorrhea at 6 months in postmenopausal women 4
Why 100mg Won't Work for Your Scenario
The 100 mg dose you're asking about is insufficient for sequential endometrial protection and won't reliably suppress periods:
- Endometrial protection requires 200 mg daily for 12-14 days in sequential regimens, not 100 mg 1, 5
- Using only 100 mg in a sequential pattern provides inadequate endometrial protection and increases risk of breakthrough bleeding 6
- Studies show that 100 mg oral progesterone in sequential regimens leads to more irregular bleeding episodes compared to 200 mg 3, 6
The Correct Approach Based on Your Goal
If You Want to Suppress Periods (Amenorrhea):
- Use continuous combined therapy: 50 mcg estradiol patch continuously + 100 mg oral micronized progesterone daily for 21-25 days per month 4
- This induces amenorrhea in >90% of women 4
- Critical caveat: This is primarily studied in postmenopausal women; if the patient is perimenopausal or has premature ovarian insufficiency, sequential regimens are typically preferred initially 1
If You Want Regular, Predictable Withdrawal Bleeding:
- Use sequential therapy: 50 mcg estradiol patch continuously + 200 mg oral micronized progesterone daily for 12-14 days per cycle 1, 2
- This produces regular monthly withdrawal bleeding in 74% of cycles 3
- Never use progesterone for fewer than 12 days per cycle—this provides inadequate endometrial protection 1
Vaginal Route Alternative
If oral progesterone causes side effects, vaginal administration provides better bleeding control:
- Vaginal micronized progesterone 100 mg daily for 12 days (days 14-25 of each cycle) combined with 50 mcg estradiol patch provides adequate endometrial protection 6
- Vaginal route at this dose shows higher rates of regular bleeding and fewer spotting episodes compared to oral 100 mg 6
- Vaginal 200 mg daily for 10+ days per month is also effective for endometrial protection 1, 5
Common Pitfall to Avoid
The most dangerous error is using 100 mg oral progesterone in a sequential pattern (12-14 days only)—this dose is too low for adequate endometrial protection in sequential regimens and increases hyperplasia risk. 6, 5 Either increase to 200 mg oral for sequential use, or switch to continuous combined therapy with 100 mg daily for 21-25 days. 1, 4