Hyperreactio luteinalis (HL) is a rare benign complication of pregnancy that is characterized by progressive ovarian enlargement and hyperandrogenism. We present a case of a 30-year-old woman with a spontaneous monochorionic diamniotic twin pregnancy who presented with early-onset preeclampsia, concern about possible twin-twin transfusion syndrome, and bilateral enlarged ovarian masses. Both ovaries had multiple thin-walled unilocular cysts; one ovary measured 17.9 × 17.5 × 9.1 cm and the other 12.5 × 11 × 12.3 cm. After extensive counseling, the patient underwent an uncomplicated dilation and evacuation. Postoperative assessment indicated elevated androgen levels, which spontaneously resolved, supporting the clinical diagnosis of HL. It is important to consider HL in the differential diagnosis of adnexal masses in pregnancy. HL spontaneously regresses after delivery and is managed expectantly. HL has been associated with gestational trophoblastic disease, multiple gestations, preeclampsia, and twin-twin transfusion syndrome.