[Ovarian hyperstimulation syndrome in a spontaneous pregnancy]

Ovarian hyperstimulation syndrome (OHSS) is considered to be an iatrogenic complication of ovulation induction therapy. However, OHSS may rarely be associated with spontaneous ovulatory cycles, usually in multiple or molar gestations or hypothyroidism. Clinical manifestations vary and may be potentially fatal in severe cases.

A 28-year-old primigravid, with no history of an infertility treatment, presented with enlarged ovaries and ascite. The patient had minor abdominal discomfort, without other complains. Ultrasound evaluation showed enlarged cystic ovaries and mild ascites. Hormonal profile revealed increased estradiol levels, with normal TSH and hCG. The patient was managed expectantly with no complications.

Although spontaneous OHSS is a rare entity, it is important to consider it in cases of bilateral ovarian masses in pregnancy. Three different mechanisms responsible for the occurrence of spontaneous OHSS have been described. This syndrome is thought to be secondary to promiscuity of the FSH receptor for hCG and/or TSH. It may occur with normal or increased levels of hCG and/or TSH.