Background: Ovarian hyperstimulation syndrome, not related to ovulation induction, is rare. A MEDLINE search from 1987 to 1997 using the key words "spontaneous ovarian stimulation," "pregnancy," and "hypothyroidism" revealed only five cases: three associated with pregnancies and two with primary hypothyroidism.
Case: A 25-year-old white gravida 2, para 1, at 11-12 weeks' gestation presented with mild distension of a nontender abdomen, myxedematous facies, and large bilateral, multilobulated ovarian cysts. Conception had occurred spontaneously. Thyroid stimulating hormone was elevated, and free triiodothyronine and free thyroxine were low. Hypothyroidism, associated with spontaneous ovarian hyperstimulation syndrome, was diagnosed, and oral levothyroxine (0.10 mg/day) was started. With TSH still elevated at 21 weeks, levothyroxine was increased to 0.20 mg/day, and by 24 weeks, TSH and ovarian size were normal. Vaginal delivery of a 1120 g male infant occurred at 28 weeks.
Conclusion: A case of naturally conceived pregnancy associated with spontaneous ovarian hyperstimulation and primary hypothyroidism is reported.