The significance of gender in fetuses with increased nuchal translucency: pregnancy outcomes and long-term outcomes of children.

OBJECTIVE

We aim to study the gender impact on the pregnancy outcome and on the long-term outcome of children after increased fetal nuchal translucency.

METHOD: All singleton pregnancies with increased nuchal translucency (≥3 mm until 1 March 2004 and ≥95th percentile thereafter) referred to Helsinki University Hospital from 2002 to 2007 with known gender and normal sex chromosomes were included. The pregnancy outcome (miscarriage, termination of pregnancy, perinatal death or delivery of a healthy/unhealthy child) and the long-term outcome (structural defects or neurodevelopmental impairment) were recorded from hospital databases and national registers.

RESULTS

Of the 1011 fetuses, 600 were male and 411 were female, male-to-female ratio being 1.46 : 1. This ratio decreased by increasing NT thickness, being 1 : 1 when the NT was ≥4.0 mm. The pregnancy outcome was better among male fetuses than among female fetuses (p = 0.049). There were more chromosomal abnormalities among the females than the males (p = 0.04). Among euploid fetuses, the pregnancy outcome and the long-term outcome were equal.

CONCLUSION

After increased nuchal translucency, the pregnancy outcome of male fetuses was better due to the lower incidence of chromosomal abnormalities compared with female fetuses. Among euploid fetuses, the pregnancy outcome and the long-term outcome were equal.