Heterotopic pregnancy in a natural conception cycle presenting as hematometra

BACKGROUND: Heterotopic pregnancy is a rare event in natural conception cycles. Diagnosis of heterotopic pregnancy requires a high index of suspicion. Described herein is a reported case of a heterotopic pregnancy presenting as hematometra. CASE: A young, multiparous woman, with her last menstrual period 6 weeks before presentation, complained of a dark reddish-brown vaginal discharge and progressive left lower-quadrant discomfort during early pregnancy following a natural conception cycle. An intrauterine mass was observed, and subsequently a heterotopic pregnancy complicated by hematometra was diagnosed with the help of transvaginal ultrasonography and 3-dimensional power Doppler ultrasound angiography. CONCLUSION: Women with intrauterine fluid accumulation during pregnancy may be at risk for coexistent ectopic pregnancy. High resolution transvaginal color Doppler sonography may be useful to identify a heterotopic pregnancy preoperatively.