The role of fetal nuchal translucency in prenatal screening

An update of findings from studies on first trimester nuchal translucency screening.

New first trimester markers can substantially improve efficacy of screening. When fully informed, preliminary data indicate that women prefer first trimester above second trimester testing.

Recent reports on nuchal translucency screening reiterate the importance of standardization of technique and quality control as proposed by the Fetal Medicine Foundation in London. Effective quality control can be achieved through quantitative analysis of operator specific data. Three-dimensional ultrasound does not provide substantially higher success rates in obtaining reliable nuchal translucency measurements than two-dimensional ultrasound. New data confirm the previously reported association between increased nuchal translucency and increased rate of spontaneous fetal loss, genetic syndromes and a high prevalence (15%) of anomalies, among which cardiac defects are the commonest. Researchers agree that increased nuchal translucency ought to be an indication for specialized echocardiography. Promising data have become available on new markers that can enhance first trimester screening. It is estimated that when assessment of nasal bone and maternal serum analytes are taken into account, first trimester screening can identify 97.5% of trisomy 21 pregnancies for a 5% false-positive rate. It is stressed that parents need to be informed about the possible implications of screening before testing. Preliminary data indicate that when appropriately informed, women prefer first trimester above second trimester testing. Furthermore, the uptake of screening is likely to be relatively low among younger women.