Natural conception complicated by spontaneous ovarian hyperstimulation syndrome in the setting of severe primary...

Spontaneous ovarian hyperstimulation syndrome (sOHSS) occurring in naturally conceived pregnancies is exceedingly rare, particularly when associated with untreated primary hypothyroidism. Misdiagnosis may result in unnecessary interventions, whereas delayed diagnosis can worsen disease progression.

Four pregnant women presented with bilateral, multiloculated ovarian cysts (>10 cm), markedly elevated thyroid-stimulating hormone levels, and mild-to-moderate dilutional anemia. Two patients exhibited significant abdominal distension accompanied by markedly elevated β-human chorionic gonadotropin levels, while 3 displayed classic hypothyroid symptoms.

All cases were diagnosed with severe primary hypothyroidism complicated by secondary sOHSS.

Three patients were treated with levothyroxine (LT4). The fourth patient underwent an unnecessary laparoscopic cystectomy due to initial misdiagnosis; postoperatively, fetal cleft lip and palate were identified on ultrasound.

The 3 patients receiving LT4 therapy achieved complete resolution of their ovarian cysts. The misdiagnosed case resulted in pregnancy termination following the detection of fetal abnormalities.

In the evaluation of bilateral ovarian cysts during naturally conceived pregnancy, sOHSS secondary to hypothyroidism should be considered. Multidisciplinary consultation is advised, along with a comprehensive assessment of thyroid function, β-human chorionic gonadotropin, and follicle-stimulating hormone receptor levels. Timely medical intervention with levothyroxine can prevent disease progression and promote cyst resolution, thereby avoiding unnecessary surgical procedures. Enhanced clinical recognition of this rare yet treatable condition is critical for ensuring optimal patient management.