Targeted Post-Peak Progesterone Series (Peak +3, +5, +7, +9, +11)
The Peak Plus Series is a NaProTechnology and Creighton Model protocol of serial serum progesterone draws timed to specific days after the identified Peak Day, designed to characterize progesterone production across the full arc of the luteal phase rather than at a single point in time.
Standard reproductive workups rely on a single progesterone draw timed to mid-cycle by calendar estimate. That approach produces a single data point with no reference to where in the luteal arc the sample was obtained. It cannot confirm that the Peak Day was correctly identified, nor can it distinguish an adequate luteal phase from a deficient one at different phases of luteal activity.
The Peak Plus Series uses the identified Peak Day as a biological anchor rather than a calendar date. Draws are obtained across both the early and late post-Peak phase, generating a longitudinal profile of corpus luteum output.1 The protocol also provides an early-luteal reference point that can confirm whether ovulation occurred, separate from whether the luteal phase was hormonally adequate.2
This multi-draw approach identifies patterns of luteal phase deficiency that a single mid-luteal draw cannot resolve: early-luteal deficits, late-luteal drop-offs, and integrated insufficiency across the phase.34 Corpus luteum deficiency may contribute to any of these patterns. The profile also reflects the quality of follicle development that preceded ovulation: a poorly developed follicle produces a structurally compromised corpus luteum.
Because the protocol is anchored to the biological Peak Day identified through Creighton Model charting, it requires NaProTechnology training and cycle chart data to execute. Calendar-based timing produces misaligned draws and unreliable results.
Cited in this entry
- Hilgers TW. The Medical and Surgical Practice of NaProTECHNOLOGY. Pope Paul VI Institute Press; 2004. https://rrmacademy.org/library/the-medical-surgical-practice-of-naprotechnology-rectiyuppdjrktphh/
- Hilgers TW. The Identification of Postovulation Infertility with the Measurement of Early Luteal Phase (Peak Day +3) Progesterone Production. Linacre Q. 2020. https://rrmacademy.org/library/the-identification-of-postovulation-infertility-with-the-measurement-of-early-lu-recad1q3vueuhqgsl/
- Progesterone and the Luteal Phase: A Requisite to Reproduction. https://pmc.ncbi.nlm.nih.gov/articles/PMC4436586/
- Diagnosis and treatment of luteal phase deficiency: a committee opinion. https://www.asrm.org/practice-guidance/practice-committee-documents/diagnosis-and-treatment-of-luteal-phase-deciency-a-committee-opinion-2021/
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.