Ovarian hyperstimulation syndrome (OHSS) is ovarian enlargement secondary to hormones overstimulating ovarian growth. It can be associated with a spectrum of other clinical findings, including ascites, hemoconcentration, hypercoagulability, and electrolyte imbalances. OHSS most commonly occurs as a complication of treatment with in vitro fertilization medications, such as human chorionic gonadotropin (hCG) or gonadotropin-releasing hormone agonists. OHSS has infrequently been reported to be caused by high hCG levels in complete, partial, or invasive molar pregnancies. The classic signs and symptoms of OHSS include nausea, vomiting, bloating, abdominal pain, tachycardia, tachypnea, and dyspnea. Further positive diagnostic studies for OHSS include enlarged ovaries, ascites, hemoconcentration, hyponatremia, hyperkalemia, and oliguria. OHSS due to molar pregnancies is extremely rare. Suziki et al. performed a literature review in 2014 and describe the eight ever-reported molar pregnancy-associated OHSS cases, three of which were partial molar pregnancies. We present a two-case comparison that first examines an exceptionally rare OHSS case presentation of a 19-year-old female with a partial molar pregnancy that was also complicated by hCG-induced thyrotoxicosis. Following this, we discuss a case of the more classic presentation of OHSS caused by fertility treatments. This case report is of novel interest because we present a case comparison that emphasizes a rare, paradoxical association between OHSS and dilation-evacuation procedures that is important for physicians to be aware of - OHSS is not an adverse event of molar pregnancies that can be eliminated by declining hCG levels after a dilation and evacuation procedure; rather, in a molar pregnancy, OHSS occurs after the dilation and evacuation.
Keywords: dilation and evacuation; fertility treatment; ovarian hyperstimulation syndrome; partial molar pregnancy; thyrotoxicosis.