[First trimester nuchal translucency thickness in normal fetuses in the Bulgarian population]

Nuchal translucency (NT) measurement between 11-14 weeks of gestation is an effective method of ultrasound screening for chromosomal fetal anomalies. The aim of the present study is to construct normal reference ranges of NT thickness for the Bulgarian population. The choice of cut-off NT thickness above which an invasive procedure should be offered is discussed.