EP21.22: Intramural heterotopic pregnancy: a case report and review of the literature

Heterotopic pregnancy (HP) is a rare and life-threatening condition in which an ectopic pregnancy occurs with an intrauterine pregnancy (IUP). Intramural HP is when a second gestational sac (GS) is visualised surrounded by myometrium. We report a case of intramural HP in a 24 year old G4 P2012 female, with a history of miscarriage, who presented for evaluation at an outside centre. TVUS revealed an IUP with a CRL of 6mm and FHR of 99bpm, consistent with 6w3d gestation. Her β-hCG was 64,116 mIU/mL. There was also a distinct cystic structure with an echogenic rim and peripheral flow measuring 14x11mm. She was referred to our unit for evaluation. Repeat US at 7w1d confirmed a viable embryo with CRL 16.9mm and an intramural HP with a GS of 8mm. At 8w2d, there was a viable embryo with CRL 22.2mm and 3D US localised the HP to the left lateral inferior uterine wall with a well-demarcated, vascularised 6-7mm GS. Follow-up US at 9w0d revealed an embryo with CRL 22.4mm and complete resorption of the HP. The pregnancy continued without complications. A live-born neonate was delivered at 40w0d, weighing 3680 g. A scoping review of heterotopic and/or intramural pregnancy was conducted using PRISMA-ScR guidelines. PubMed/MEDLINE, Embase, Web of Science, Scopus, and Cochrane Reviews were searched. Ten relevant cases were reviewed with ours. Risk factors for intramural HP include history of IVF, uterine trauma, prior Caesarean, PID, adenomyosis, and IUDs. Patients were either asymptomatic or had abdominal pain with gestational ages of 6-32 weeks. Treatments were as follows: 45% expectant management, 36% laparoscopy, 9% hysteroscopy, 9% laparotomy and 9% Caesarean section. Pregnancies resulted in 82% live births, 9% miscarriages, and 9% terminations. In conclusion, treatment options should be individualised. In subsequent conception, patients should be monitored closely. A strong index of suspicion and early diagnosis is crucial to preserving the health and future fertility of the mother.