The clinical evaluation and pregnancy outcome of euploid fetuses with increased nuchal translucency

Abstract

This review aims to address the systematic work-up and counseling throughout pregnancies with increased nuchal translucency (NT) in euploid fetuses. Original articles from peer-reviewed English-language journals between 1997 and 2003 were studied. They all included descriptions of pregnancy outcomes of euploid fetuses with increased NT. Eleven studies reporting on the pregnancy outcome of 2128 euploid fetuses with increased NT (> or = 3 mm or > or = 95 centile) were retrieved by our literature search. A statistical analysis was conducted for assessing the consistency of effects across studies. The chi2 tests were applied to verify the homogeneity of the results from different series. A significant difference was found between the studies even when the results were analyzed separately according to various NT cutoff levels (i.e. > or = 3 mm, > or = 3.5-4 mm, and > or = 95 centile). These discrepancies suggest that those studies are significantly different and therefore, cannot be combined for meta-analysis. Of all the reported series, 2.2-10.6% of the fetuses have miscarried and 0.5-15.8% ended in perinatal death. There was an overall rate of 0.5-12.7% neurodevelopmental problems, and 2.1-7.6% of the malformations which were undiagnosed before birth. Importantly, 70-90% fetuses had normal outcomes. A detailed two-step anomaly scan including midgestation fetal echocardiography should be part of perinatal management of pregnancies with increased fetal NT. Data on relevant family history and persistence of nuchal edema provide additional relevant information for planning pregnancy management.

Increased nuchal translucency thickness and normal karyotype: time for parental reassurance

“…The reported incidence of neurodevelopmental delay in fetuses with increased NT and normal chromosomes, whether or not in the setting of a recognizable genetic syndrome, varies from 0 to 13%5–8, 14, 31–39. However, different cut‐offs used for the definition of increased NT and differences in the completeness and length of postnatal follow‐up make comparison of studies difficult.…”

Increased nuchal translucency in euploid fetuses—what should we be telling the parents?

“…The five largest studies published since 2000 comprise a total of 2271 fetuses and report a mean incidence of 10.6% (range 2.1-26%) for isolated structural anomalies and 4.4% (0.5-6.4%) for genetic disorders detected before birth with an additional 2.5% (2.2-6.6%) of anomalies detected after birth (Michailidis and Economides, 2001;Souka et al, 2001;Senat et al, 2002;Bilardo et al, 2007) (Table 3). However, these studies are difficult to compare (Maymon and Herman, 2004b) due to differences in populations, definitions of NT enlargement (3 mm, 95th centile, 99th centile or 4 mm) and NT distribution (Maymon and Herman, 2004a). Table 4 gives an overview of the frequency of various outcome variables according to degree of NT thickness .…”

Increased Fetal Nuchal Translucency Thickness and Normal Karyotype: Prenatal and Postnatal Outcome

“…As Bilardo CM et al [14] pointed out, the most unpredictable aspect of increased NT is neurodevelopmental delay, which could be manifested unexpectedly, in the postnatal period. The reported incidence of neurodevelopmental delay in fetuses with or without recognizable genetic syndrome varies from 0 to 13% [14,25,26]. In our study 10.4% of newborns (5 out of 48) were diagnosed during the follow-up period of at least 18-months.…”