First trimester cystic hygroma colli: Retrospective analysis in a tertiary center.

<bold>Objective: </bold>This retrospective study aims to evaluate the incidence, presence of chromosomal anomalies and outcome of fetuses diagnosed with cystic hygroma colli in the first trimester in a single tertiary center.<bold>Study Design: </bold>A retrospective study was performed over a ten-years period from 2007 to 2017 of all fetuses with a first-trimester diagnosis of cystic hygroma. Maternal and fetal parameters were assessed with descriptive statistics.<bold>Results: </bold>A total of 185 singleton pregnancies were included. Chromosomal anomalies were present in 122 cases (65.9%). Sixty-three fetuses (34.1%) had a normal karyotype. Noonan syndrome was diagnosed in 6 cases using additional testing for RASopathies. In euploid fetuses, a major congenital anomaly was detected in 35 of 63 cases (56%) and if present, 91.4% had an abnormal fetal outcome compared to 32.1% if no structural anomaly was found (p < 0.01). Fetuses with a nuchal translucency thickness more than 10 mm and hydropic fetuses had a worse outcome.<bold>Discussion: </bold>Associated structural anomalies or hydrops fetalis are significant predictors for an abnormal outcome in pregnancies with first-trimester cystic hygroma and a normal karyotype. Cytogenetic evaluation and detailed sonographic evaluation are of great importance in the determination of the prognosis of pregnancies complicated by first-trimester cystic hygroma. [ABSTRACT FROM AUTHOR]