Primary omental pregnancy in a subseptate uterus: A novel case report and literature review

INTRODUCTION AND IMPORTANCE: Ectopic pregnancy is defined as a pregnancy in which the fertilized ovum implants itself in a location other than the uterine endometrium. Abdominal ectopic pregnancies involve the implantation and development of the embryo within the peritoneal cavity. Primary omental pregnancies are the rarest form of abdominal pregnancy and possibly the rarest extrauterine gestation. CASE PRESENTATION: We report the first case of a primary omental pregnancy in a subseptate uterus in literature. Our patient, a 33-year-old female, G8P4+3, presented with nausea, severe abdominal pain, and vaginal spotting at 6 weeks’ gestational age. She had mild tenderness below the umbilicus, with positive cervical and right adnexal tenderness. 2D-ultrasound revealed a subseptate uterus, normal ovaries and fallopian tubes, absence of a gestational sac, and a 4x3x2.5 cm mass in the right adnexa. A mini-laparotomy was performed due to suspicion of ruptured tubal pregnancy, revealing a primary omental pregnancy which was managed via partial omentectomy. CLINICAL DISCUSSION: Ectopic pregnancies have ambiguous presentations, however correct diagnosis and management is crucial to prevent complications. A high index of suspicion must be exercised to make an accurate diagnosis of primary omental pregnancy. A subseptate uterus is a subtype of the most common uterine anomaly and should be investigated via 3D-ultrasound and magnetic resonance imaging as it causes increased risk of primary omental implantation. CONCLUSION: Correct identification of subseptate or septate uteri is vital. Greater research is needed to elucidate the association between septate or subseptate uteri and ectopic pregnancy, particularly primary omental pregnancy.