Nasal bone in screening for Trisomy 18 and 13 at 11-13 + 6 weeks of gestation - own experiences.

Objectives: The objective of the paper is the suitability assessment of screening for Trisomy 18 and 13 on the basis of NT measurement, FHR, double test and assessment of Nasal Bone. Material and methods: The study was performed in 6,661 singleton pregnancies. In each fetus NT, FHR, DV-PIV were examined. Double test from maternal blood was examined. These ultrasound and biochemical factors were in combined screening investigated. Additional ultrasound marker — Nasal Bone was and its impact on Trisomies 18 and 13 screening was examined. Results: Two groups of patients were compared — with chromosomal normal and chromosomal abnormalities — Trisomy 18 and 13. Detection Rate of Trisomies 18 and 13 at the risk cutoff 1/300 using combined screening was 84.1% and FPR was 7.1%. Detection Rates of examined chromosomal abnormalities using screening with additional marker — NB was 93.2% and False Positive Rate — 5.6%. Conclusions: It should be noted that the qualitative analysis of the assessment of NB in the first trimester significantly influences the improvement of screening values focusing on Trisomy 18 and 13 detection. In summary, our research indicates a more effective type of Trisomy 13 and 18 screening using NT, double test, maternal age, CRL and FHR as well as nasal bone presence and absence.