[Fetal abnormalities and prognosis associated with increased nuchal translucency and abnormal karyotype]. / Anomalias e prognóstico fetal associados à translucência nucal aumentada e cariótipo anormal.

OBJECTIVES: This study aimed to evaluate the incidence of chromosomal abnormalities in fetuses with increased nuchal translucency (NT) measurement. Incidence of structural abnormalities and pregnancy outcome was also described in fetuses with increased NT and abnormal karyotype. METHODS: This was a retrospective study involving 246 fetuses with increased NT and known karyotype followed at the Fetal Medicine Unit, Hospital das Clínicas, São Paulo University Medical School. RESULTS: Fetal karyotype was abnormal in 14.2% of the cases. Ultrasound anomaly scan and specialized echocardiographic studies in these cases showed fetal structural abnormalities in 80.8% and cardiac defects were found in 61.5% of the fetuses. Pregnancy outcome was abnormal in 76.5% of these women. CONCLUSION: Increased NT measurement at 11 to 13 weeks and 6 days is an important marker for fetal chromosomal and structural abnormalities, mainly fetal cardiac defects. This finding also indicates increased risk of spontaneous fetal and neonatal death.

Nuchal translucency: an ultrasound marker for fetal chromosomal abnormalities.

CONTEXT: The literature shows an association between several ultrasound markers and chromosome abnormality. Among these, measurement of nuchal translucency has been indicated as a screening method for aneuploidy. The trisomy of chromosome 21 has been most evaluated. OBJECTIVE: To define the best fixed cutoff point for nuchal translucency, with the assistance of the ROC curve, and its accuracy in screening all fetal aneuploidy and trisomy 21 in a South American population. TYPE OF STUDY: Validation of a diagnostic test. SETTING: This study was carried out at the State University of Campinas, Campinas, Brazil. PARTICIPANTS: 230 patients examined by ultrasound at two tertiary-level private centers, at 10 to 14 weeks of gestation. DIAGNOSTIC TEST: The participants consisted of all those patients who had undergone ultrasound imaging at 10 to 14 weeks of gestation to measure nuchal translucency and who had had the fetal or neonatal karyotype identified. MAIN MEASUREMENTS: Maternal age, gestational age, nuchal translucency measurement, fetal or neonatal karyotype. RESULTS: Prevalence of chromosomal defects - 10 %; mean age - 35.8 years; mean gestational age - 12 weeks and 2 days; nuchal translucency (NT) thickness - 2.18 mm. The best balance between sensitivity and specificity were values that were equal to or higher than 2.5 mm for overall chromosomal abnormalities as well as for the isolated trisomy 21. The sensitivity for overall chromosomal abnormalities and trisomy 21 were 69.5 % and 75 %, respectively, and the positive likelihood ratios were 5.5 and 5.0, respectively. CONCLUSION: The measurement of nuchal translucency was found to be fairly accurate as an ultrasound marker for fetal abnormalities and measurements equal to or higher than 2.5 mm were the best fixed cutoff points.