NT >99th centile and cystic hygroma: Which diagnosis, which management and outcome

Objectives To evaluate the prevalence of chromosomal anomalies in fetuses affected by increased nuchal translucency(iNT >99Th centile), cystic hygroma (CH) and cases progressing to fetal hydrops (NIHF) in order to correlate this result to prognosis and perinatal fetal outcomes, improving patient's counseling. Methods From January 2020 to December 2023, first trimester screening according to FMF criteria were performed in “Maternal fetal medicine Unit” of Foggia's hospital. We studied and collected clinical data of fetuses affected by nuchal translucency >99th centile (iNT), CH and cases progressing to Fetal Hydrops (non‐immune fetal hydrop, NIFH). In these selected cases, we evaluated fetal Karyotype to demonstrate the presence of chromosomal abnormalities, associated to fetal structural anomalies and different pregnancy outcome. Results We have evaluated 45 cases of iNT, CH, and NIFH, identified by ultrasound during first trimester screening. Of these 45 pregnant women, four were lost to follow‐up. Of the 41 pregnancies, 20 cases (48.8%) delivered at our division with newborns discharged in good health. Of the 21 patients (51.2%) who miscarried, only two miscarried spontaneously; the other 19 decided on a medical termination of pregnancy (MTP). The 19 patients who decided for MTP showed genetic abnormalities and/or malformation. The 20 cases of fetuses discharged as healthy newborns were enrolled with the following diagnoses: 5 had a diagnosis of CH (20% of cases), 1 case of NIFH (5% of cases), and 14 of iNT (75% of cases). All these fetuses had a normal karyotype and no major malformations. Conclusions Isolated CH diagnosis is more frequent than described in Literature (5 cases out of 12: 41.7%) and their prognosis are better than previously described, with the same outcomes of fetuses with iNT without associated anomalies. The possibility of early diagnosis of chromosomal anomalies, associated malformations or the evolution into hydrops is essential for a complete consultation. To investigate rate of chromosomal anomalies, prognosis, and perinatal outcomes in fetuses affected by increased nuchal translucency (iNT >99° centile) and cystic hygroma (CH). In this study, we aimed to demonstrate a higher rate of isolated cases of CH than cases described in Literature and their correlation with a better fetal outcomes.