Partial Rupture Syndrome (PRS)

By RRM Academy Reviewed by Dr. Naomi Whittaker, MD, Board-Certified OBGYN, MIGS, NFPMC, FCI Updated May 14, 2026

Partial Rupture Syndrome (PRS) is an ovulation disorder in which the dominant follicle decreases in size at the expected time of ovulation but does not fully collapse, leaving a partial cystic residual rather than completing the rupture process.¹ Rupture initiates but stalls. The oocyte-cumulus complex is not fully expelled.

Dr. Thomas W. Hilgers formalized PRS as a distinct sonographic entity within the NaProTechnology follicle-maturation-study protocol.¹ The diagnosis is made by trained sonographers reviewing serial ultrasound images across the periovulatory window: the pattern of partial size decrease without full collapse distinguishes PRS from normal ovulation, and from the other rupture-spectrum disorders classified in this system. No specific collapse threshold in millimeters or time interval defines the diagnosis in isolation.

PRS occupies a specific position within Hilgers’ sonographic classification of ovulation disorders. It is distinct from Luteinized Unruptured Follicle Syndrome, where no collapse occurs at all. It is distinct from Delayed Rupture Syndrome, where full collapse eventually occurs but later than expected. And it is distinct from Empty Follicle Syndrome, where collapse appears complete but no oocyte is recovered.

The corpus luteum that forms from a partially ruptured follicle is structurally compromised. Subnormal corpus luteum function follows, with reduced progesterone output across the post-Peak phase. Fecundity in affected cycles is reduced even when the cycle chart shows apparently normal ovulation timing. Serial follicle maturation study ultrasound names the defect. Chart observation alone cannot distinguish PRS from a normal ovulatory cycle.

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.