Does the Presence of Extended Jugular Lymphatic Sacs Add More Risk to Nuchal Thickness for Genetic and Structural Abnormality?

Background: The risks added by extended jugular lymphatic sacs (EJLS) to increased nuchal translucency (NT) including genetic and structural abnormalities and pregnancy outcomes have not been previously investigated, which this study aims to investigate.

Methods: The data of 155 singleton pregnancies with increased fetal NT (≥95^th percentile) of these 20 with fetal EJLS were evaluated retrospectively. Patients were stratified according to NT thickness such that ≥95^th percentile - 3.5 mm, 3.6-4.4 mm, 4.5-5.4 mm, 5.5-6.4 mm, ≥6.5 mm, and grouped according to the presence of EJLS. Pregnancy outcomes, genetic and structural abnormalities were assessed by comparing EJLS with non-EJSL cases (n-EJLS).

Results: Associated with NT, the incidence of the presence of EJLS increased with NT, from 4.5% at the ≥95^th percentile - 3.5 mm to 30.8% when NT ≥5.5 mm. In the n-EJLS group, the proportion of fetuses with structural and genetic abnormalities increased as the measurement of NT increased. This correlation was not observed in the EJLS group. Compared to n-EJLS, cases with EJLS had a higher rate of fetal structural (38.5% vs. 75%, P = 0.003) and genetic (18.5% vs. 45%, P = 0.005) anomalies and a lower term live birth rate (59.3% vs. 15%, P < 0.001).

Conclusion: The increasing rate of EJLS was seen as NT increased. Compared to n-EJLS, the EJLS cases had a higher rate poor pregnancy outcomes and fetal genetic and structural abnormalities.