Targeted Post-Peak Progesterone Series (Peak +3, +5, +7, +9, +11)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 7, 2026

The Targeted Post-Peak Progesterone Series is a Hilgers-developed protocol of five serial serum progesterone draws obtained at Peak Day +3, +5, +7, +9, and +11, designed to characterize the full luteal-phase hormonal profile rather than a single mid-luteal snapshot.

Standard reproductive endocrinology relies on a single "day-21 progesterone" draw. That number tells you almost nothing. It cannot distinguish an adequate luteal phase from a deficient one, and it cannot locate where in the luteal arc the deficit falls. The Peak +3 through +11 series captures early, mid, and late luteal output in a single protocol block. Results are interpreted as individual raw values, three-value sums (Peak +5/+7/+9), four-value sums, and five-value means.

The Peak +3 draw carries its own diagnostic weight. Hilgers established two clinical thresholds: a value of 2.3 ng/mL or higher confirms ovulation has occurred; 3.0 ng/mL or higher marks the beginning of the absolute postovulation period of infertility.⁸¹ The full five-point series identifies Type I through V luteal phase deficiency, distinguishing early-luteal, late-luteal, and integrated deficits that require different restorative hormonal protocols.⁷⁸ Reduced luteal output may also reflect corpus luteum deficiency or a disorder of Peak Day identification. Cycle-timed measurement, not a calendar estimate, is what makes the data actionable.

This content is for educational purposes only and does not constitute medical advice. Consult an RRM clinician or healthcare provider for guidance specific to your situation.