Ovarian Hyperstimulation Syndrome (OHSS)

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

Ovarian hyperstimulation syndrome is a complication of ovarian stimulation, most commonly occurring in the context of IVF. High doses of gonadotropins cause the ovaries to produce far more follicles than they would in a natural cycle. In susceptible women, this triggers a cascade of vascular permeability changes, fluid shifts, and electrolyte disturbances that can range from mild discomfort to a life-threatening medical emergency.

Mild OHSS is common. Severe OHSS requiring hospitalization is less frequent but not rare. Major professional societies have published guidance on classification and prevention, recognizing OHSS as an iatrogenic complication of ovarian stimulation protocols.⁶² Women with PCOS are at significantly higher risk because their ovaries already contain a large number of antral follicles that respond aggressively to stimulation.

OHSS does not occur in restorative reproductive medicine protocols. RRM uses low-dose, cycle-timed hormonal support to assist the body's own follicle development. Medications are used at physiologic doses to correct documented deficiencies, not to override the ovarian cycle with pharmacologic superstimulation. The risk of OHSS is specific to the ovarian stimulation paradigm, not to hormonal medicine broadly.

For women with PCOS who are offered IVF, OHSS risk should be part of an honest informed consent discussion. There are risk-reduction strategies within IVF protocols. But the more fundamental question is whether stimulation for IVF is the right starting point when the underlying cause of anovulation has not been evaluated or treated. Many women with PCOS can achieve natural conception with appropriate cycle support once the hormonal and metabolic contributors are identified.

OHSS is one of several reasons why RRM clinicians evaluate PCOS and anovulatory cycles with a restorative approach first. The goal is to support the cycle the patient has, not to replace it with an artificially stimulated one that carries its own risks.

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.