No, taking progesterone 200 mg daily from days 15-28 will NOT help you ovulate or get pregnant—it will actually prevent ovulation.
Progesterone suppresses ovulation rather than promoting it. When you take progesterone during the second half of your cycle (days 15-28), you are mimicking what happens AFTER ovulation has already occurred, not creating conditions for ovulation to happen. This is fundamentally why progesterone-only contraceptives work—they prevent ovulation by providing continuous progesterone signaling 1.
Why This Approach Won't Work
The timing is backwards for fertility:
- Ovulation typically occurs around day 14 of a 28-day cycle
- By starting progesterone on day 15, you've already missed the ovulation window
- Progesterone levels naturally rise AFTER ovulation occurs, not before
- Taking exogenous progesterone signals your body that ovulation has already happened, which suppresses further ovulatory activity
Progesterone's contraceptive mechanism: Studies examining combined hormonal contraceptives demonstrate that 7 consecutive days of hormonal suppression is sufficient to prevent ovulation 1. Your proposed 14-day regimen (days 15-28) would maintain ovulation suppression throughout the luteal phase and into the next cycle's follicular phase.
What Progesterone Actually Does in Fertility Treatment
Progesterone has legitimate fertility uses, but in completely different contexts:
For Luteal Phase Support (AFTER ovulation/embryo transfer):
- Used in assisted reproductive technology (ART) to support implantation 2, 3
- Given AFTER ovulation has occurred or embryos are transferred
- Typical dose: 200 mg vaginal progesterone daily 4
- This supports an existing pregnancy, doesn't create ovulation
For Secondary Amenorrhea (to induce withdrawal bleeding):
- 400 mg daily for 10 days can induce a withdrawal bleed 5
- This tests whether your endometrium responds to progesterone
- It does NOT restore ovulation—it only produces bleeding when stopped
If You're Trying to Conceive
You need to address the underlying cause of anovulation, not just add progesterone:
For functional hypothalamic amenorrhea with infertility:
- First-line: Pulsatile GnRH therapy (currently unavailable in US) 6
- Second-line: Gonadotropin therapy for ovulation induction 6
- Alternative: Clomiphene citrate if sufficient endogenous estrogen present 6
Critical pitfall to avoid:
Taking progesterone when you're trying to conceive without proper ovulation induction will likely REDUCE your chances of pregnancy by suppressing any spontaneous ovulation attempts your body might make.
The evidence is clear: Progesterone given during days 15-28 mimics the post-ovulatory state and maintains hormonal suppression. Studies on missed contraceptive pills show that extending hormone-free intervals allows follicular development and potential ovulation, while continuous hormonal exposure (like your proposed regimen) prevents it 1.
If you're experiencing irregular cycles or anovulation, you need proper fertility evaluation and treatment—not self-administered progesterone cycling. See a reproductive endocrinologist who can determine why you're not ovulating and provide appropriate ovulation induction therapy.