Magnetic resonance imaging in evaluation of a second-trimester ovarian twin pregnancy

Ovarian pregnancy presents with abdominal pain and menstrual irregularities, and usually results in hemorrhage and hemoperitoneum in the first trimester. We describe the first case of a twin ovarian pregnancy diagnosed in the second trimester. Magnetic resonance imaging (MRI) was used in the preoperative evaluation of this patient.

A woman presented at 19 weeks' gestation with abdominal pain and irregular bleeding. Her hemoglobin level was 5.9 g/dL, as compared to 10.8 g/dL in early pregnancy. Ultrasound showed a twin gestation with a mass anterior to the pregnancy, thought to be a placenta percreta or a hemorrhagic leiomyoma. An MRI was suspicious for an extrauterine pregnancy, showing the uterus displaced anteriorly by the pregnancy mass. Laparotomy revealed a hemoperitoneum and right twin ovarian pregnancy. A right salpingo-oophorectomy was performed. Pathology confirmed the diagnosis.

Although ultrasound is the primary technique of imaging the pelvis during pregnancy, MRI should be considered when the ultrasound findings are limited or confusing.