Heterotopic pregnancy: a growing diagnostic challenge.

This report describes a 26-year-old female who presented at 5 weeks of gestation with intrauterine pregnancy after gonadotrophin stimulation and intrauterine insemination. The patient complained of abdominal pain, abdominal distension and nausea diagnosed as moderate ovarian hyper-stimulation syndrome (OHSS) with early pregnancy and was treated accordingly. The patient was readmitted at 7 and 9 weeks of gestation with persistent left lower abdominal pain. At 9 weeks' gestation she also had a low grade fever and since the pelvic ultrasound showed a left tubo-ovarian mass she was treated for pelvic infection. The follow-up ultrasounds in the 5th, 9th and 12th weeks showed a normal intrauterine pregnancy in addition to a persistent left adnexal mass without any suspicion of a heterotopic pregnancy. The diagnosis of heterotopic pregnancy became possible only at 13 weeks of gestation during laparotomy when the right fallopian tube showed a leaking ectopic pregnancy. A right-sided salpingostomy was carried out. The intrauterine pregnancy is still ongoing without complications.