Progesterone and Sunday Off Dosing
No, it is not safe to skip progesterone doses on Sundays—progesterone must be taken daily without interruption during the prescribed treatment period to maintain adequate endometrial protection and therapeutic efficacy.
Why Daily Dosing Without Interruption is Critical
Progesterone requires consistent daily administration throughout the prescribed duration to provide adequate endometrial protection and maintain stable hormone levels. The evidence-based regimens specify either:
- Sequential regimens: 200 mg micronized progesterone daily for 12-14 consecutive days per 28-day cycle 1, 2
- Continuous regimens: 100-200 mg micronized progesterone daily without any breaks 1, 2
The 12-14 day duration in sequential regimens is critical—shorter durations or interrupted dosing provides inadequate endometrial protection 2. This means every single day within that window must include progesterone administration.
The Pharmacological Rationale
Oral micronized progesterone undergoes >90% first-pass hepatic metabolism, which greatly limits efficacy and requires daily dosing to maintain therapeutic levels 3. Skipping even one day per week would:
- Create gaps in endometrial protection against estrogen-induced hyperplasia
- Disrupt the minimum 10-14 day exposure required to prevent endometrial cancer (relative risk 2.1-5.7 with unopposed estrogen) 4
- Compromise the dose-ranging effect that has been clearly demonstrated with consistent daily administration 4
Evidence-Based Dosing Schedules
The established regimens from major guidelines include 1, 2:
For sequential therapy:
- 200 mg oral or vaginal micronized progesterone daily for 12-14 consecutive days every 28 days
- Alternative: 10 mg medroxyprogesterone acetate daily for 12-14 consecutive days per month
For continuous therapy:
- 100-200 mg micronized progesterone daily for 25 days per calendar month 5
- Alternative: 100 mg daily continuously without breaks
Common Pitfall to Avoid
Never use progesterone for fewer than 12 days per cycle in sequential regimens or skip days within the prescribed period—this provides inadequate endometrial protection 2. Studies demonstrating endometrial safety specifically used uninterrupted daily dosing, with amenorrhea rates of 93.3% at 3 months and 91.6% at 6 months achieved only with consistent 25-day administration 5.
Clinical Context
If tolerability is an issue (such as drowsiness), the solution is to take the medication at bedtime, not to skip doses 4, 5. The only specific side effect of micronized progesterone is mild and transient drowsiness, which is minimized by bedtime administration 4.