EP21.16: Three‐dimensional sonography for the diagnosis of congenital uterine anomalies in women with eccentric pregnancy implantation: a novel approach

The eccentric implantation of pregnancies in the upper lateral aspect of the uterine cavity is poorly defined clinically and unclear whether ‘non-anomalous’ versus ‘anomalous’ uteri have prognostic impact. The aim of this study was to investigate whether differentiating between uterine anomalies that can lead to cavitary distortion has implications for the management of these pregnancies. 8 cases of first trimester eccentric pregnancy implantation in the endometrial cavity, diagnosed using two- and three-dimensional scans were identified. For each woman in the study group, 10 women identified with concentric pregnancy implantation during the first trimester were meched. The controls were doubled-matched for patient age and mode of conception. After delivery or pregnancy demise, the presence of uterine anomalies was assessed by a 3D-US examination in all patients. In the study group, an increased incidence of uterine anomalies (50.0% vs. 8.8%, P = 0.007) was found and eccentric location persisted in half of the pregnancies (n = 4; 50%), the other half migrated to a more centric location within the endometrial cavity (n = 4; 50%). The follow-up showed that all the early pregnancy demises occurred in pregnancy persisted at the eccentric location with Uterine malformations. By contrast, all the cases that migrated to a more centric location within the endometrial cavity resulted in live births, and no uterine malformations were found. This points to a significantly higher incidence of uterine anomalies diagnosed with eccentric pregnancy implantation. These advocate to differentiating between eccentric pregnancies in non-anomalous vs anomalous uteri. Non-anomalous uteri diagnosed early may resemble normal intrauterine pregnancies. Close monitoring and expectant management can be recommended. Despite small sample size, it still seems reasonable to conduct a 3D-US in these women while not -pregnant to rule out underlying uterine malformations.