Fetal Nasal Bone Length Nomogram at 11-13week +6 Days in Upper Egyptian Pregnant Women

Examination of the fetal nasal bone by ultrasound between 11- and 14-weeks’ gestation has been proposed as an additional tool in the detection of chromosomal abnormalities and assessment of nasal bone is one of the effective secondary factors. Maternal age, Nuchal translucency (NT) and free β-hCG and PAPP-A (combined test) is found to have 85-95% detection rate for fetal aneuploidy with a false-positive rate of 5% whereas combined test along with nasal bone (NB) or tricuspid flow or ductus venosus flow has detection rate of 93-96% and false positive rate of 2.5% for euploid, 60% of trisomy 21, 53% for trisomy 18 and 45% for trisomy. Absence or hypoplasia of fetal NB is usually associated with fetal trisomies. Although measurement of the NB is not currently used as a routine screening tool in prenatal sonographic evaluation, it will take its place among the powerful sonographic markers of trisomy 21 anomaly.