EP07.02: Management and outcome of fetal abdominal cysts in the first trimester: systematic review of the literature

The finding of an abdominal cyst during pregnancy has an estimated prevalence of 1 in 1000 pregnancies, mostly in second and third trimester. The detection of a fetal abdominal cyst during the first trimester scan is a rare event, whose natural history and prognosis are often unknown and unpredictable as these anomalies can be related to various underlying conditions and originate from different structures. The aim of this study is to evaluate the outcome of fetal abdominal cysts detected in the first trimester in order to understand their possible clinical significance and to offer the proper management according to the available data. We present a case report of a first trimester fetal abdominal cyst detected with subsequent diagnosis of congenital multiple arthrogryposis and we performed a systematic review of the literature to identify the incidence and the outcomes of similar cases. The systematic literature review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement and registered with PROSPERO (CRD42023491729). A total of 60 cases of first trimester abdominal cysts were included. Of these, 35% were associated with concurrent or late onset structural anomalies, as in our case report, and 65% were isolated. In pregnancies with isolated fetal abdominal cysts, 56% had a completely normal outcome. The finding of an abdominal cyst during the first trimester of pregnancy is in most cases an isolated event with a moderate to good prognosis but it could also be an early sign of other associated abnormalities, including arthrogryposis. Increased ultrasound surveillance and additional genetic testing to rule out possible associated anomalies are pivotal to assess the risk of adverse pregnancy outcomes and to provide appropriate counselling to the patient.