The hidden risk: inadvertent pregnancies in random start ovarian stimulation protocols and ovarian hyperstimulation...

To examine the risk of severe ovarian hyperstimulation syndrome (OHSS) when random-start ovarian stimulation (RSOS) is performed during an undetected, spontaneously conceived pregnancy.

A case-report.

A 24-year-old woman with polycystic ovary syndrome, a history of two early pregnancy losses, and 25 months of infertility, who underwent in vitro fertilization (IVF) with RSOS at an external fertility clinic.

The RSOS begun while an early intrauterine pregnancy was already present but unrecognized.

Onset and severity of OHSS, assessed by clinical symptoms, serum human chorionic gonadotropin levels, and the need for hospitalization or intervention.

Following oocyte retrieval, the patient suffered severe abdominal pain and significant ascites consistent with OHSS and was found to have a concurrent intrauterine pregnancy. Outpatient management failed to control her symptoms, and she required hospitalization and termination of the pregnancy. She conceived naturally six months later and delivered a healthy infant.

This case underscores the significant risk of undetected pregnancies during RSOS, which can lead to severe OHSS. It emphasizes the critical need for vigilant monitoring of progesterone and human chorionic gonadotropin levels and the implementation of strategies to detect potential pregnancies before trigger of oocyte maturation. Clinicians must weigh carefully the benefits of flexible stimulation protocols against the risks of unintended pregnancies, especially in patients with a reasonable chance of achieving spontaneous conception.