Cooperative Progesterone Replacement Therapy (CPRT)
Cooperative Progesterone Replacement Therapy (CPRT) is a NaProTechnology protocol, developed by Dr. Thomas W. Hilgers, that restores luteal phase progesterone production through cycle-timed supplementation in women with documented luteal phase deficiency or specific patterns of early pregnancy loss.1
The clinical premise of CPRT is that the timing of progesterone support matters. Supplementation aligned with the post-Peak phase, based on Peak Day charting and serial hormone assays, allows clinicians to match the body's own progesterone rhythm rather than administer support on an arbitrary schedule. Hilgers documented that luteal phase progesterone production is measurable from the earliest days of the post-Peak phase, and that deficiencies at this stage are clinically significant for fertility and pregnancy maintenance.2
CPRT is used in the context of documented corpus luteum deficiency and specific patterns of recurrent early loss, and targets the underlying hormonal deficit rather than masking it. The corpus luteum is the primary source of progesterone in early pregnancy, and its failure to produce adequate progesterone is a well-recognized cause of implantation failure and early loss.3 Major professional societies acknowledge luteal phase deficiency as a clinical entity requiring individualized evaluation and management.4
The specific drug, dose, route, and duration of support in CPRT are determined by the treating clinician based on each patient's Peak Day charting, serial assay results, and clinical presentation. The word "cooperative" in the protocol name reflects the design intention: to work with the body's own cycle rather than override it. CPRT typically uses isomolecular hormones, hormone preparations that are chemically identical to those the body produces, as part of the NaProTechnology approach to physiologic-pattern restoration.5 This protocol operates within the broader framework of NaProTechnology medical management.
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/
- Hilgers TW, Keefe CE, Pakiz KA. The Use of Isomolecular Progesterone in the Support of Pregnancy and Fetal Safety. Issues Law Med. 2015. https://rrmacademy.org/library/the-use-of-isomolecular-progesterone-in-the-support-of-pregnancy-and-fetal-safet-rec9gz3n4iplw6vym/
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.