Outcome of fetuses with increased risk of chromosomal anomalies, based on nuchal translucency measurement

Purpose: to evaluate the outcome of fetuses with risk of chromosomal anomalies over 1: 300, based on the nuchal translucency measurement, according to the Fetal Medicine Program. Methods: in the pregnancies with risk of chromosomal anomalies over 1: 300, variables like fetal karyotype, spontaneous or induced abortion, prematurity, stillbirth, neonatal death, malformations, and healthy newborn were considered. We used Fisher's exact test to compare differences in proportions between groups. Results: we selected 193 (3.6%) single pregnancies with risk of chromosomal anomalies over 1: 300. Only 165 cases fulfilled the inclusion criteria. Of these only 32.1% underwent fetal karyotyping and of which 8.5% had chromosomal anomalies (85.7% had trisomy 21). Regarding pregnancy outcomes, 4.2% were spontaneous miscarriages, 4.2% induced abortions, 4.8% were premature, 1.8% had neonatal death, 1.8% were stillborn, and 4.2% had structural malformation (85.7% congenital heart diseases). Almost 85.0% were healthy newborns. Patients with abnormal karyotyping had more induced abortions (p<0.001) and more structural malformations (p<0.001) than patients with normal karyotyping. None of the genetic diseases or miscarriages was associated with invasive procedures. Sixty-six percent of the pregnancies with prenatal diagnosis of abnormal karyotype were interrupted. Conclusion: nuchal translucency is an important screening tool for chromosomal diseases especially for low-risk pregnancies. However, counseling pregnancies with high risk of chromosomal anomalies should consider that, although these fetuses have a worse prognosis, most of the outcomes are favorable.