A Rare Case of Heterotopic Twin Pregnancy After Spontaneous Conception.

Heterotopic pregnancy is a rare condition characterized by a simultaneous presence of intrauterine pregnancy and extrauterine (ectopic) pregnancy. Due to its rarity, reports in medical literature are limited. Various risk variables have been identified, and assisted reproductive techniques have been considered the most important risk factor. A 37-year-old female, G8P5 (vaginal deliveries), after spontaneous conception, presented when her last menstrual period was five weeks and two days ago with abdominal pain. An initial ultrasound revealed an intrauterine gestational sac with a normal developing embryo. She was prescribed spasmolytics for pain and discharged. Despite treatment, the pain continued, and three weeks later the patient returned with severe abdominal pain. A repeat ultrasound confirmed a normally developing intrauterine pregnancy but also showed free fluid in the Douglas pouch and lower abdomen, raising suspicion for hemoperitoneum with unknown etiology. A diagnostic laparoscopy confirmed a rupture in the right tubal wall, likely due to a ruptured ectopic pregnancy. A salpingectomy was needed, and the intrauterine pregnancy was maintained undisturbed. The pregnancy progressed normally, and she delivered vaginally at 38 weeks. The rarity of this condition and the presence of a normal intrauterine pregnancy often delay diagnosis. Early detection is essential in preventing complications, such as tubal rupture and intraabdominal hemorrhage. It is essential to underscore that heterotopic pregnancies may occur following spontaneous pregnancies. Additionally, in patients diagnosed with intrauterine pregnancies who exhibit abdominal pain or vaginal bleeding, it is crucial to exclude the possibility of extrauterine pregnancy, including those resulting from spontaneous conception. Heterotopic pregnancy should be considered as a differential diagnosis in patients presenting with abdominal pain. The presence of an intrauterine gestational sac does not exclude the possibility of an ectopic pregnancy, and thorough examinations should be routinely performed.