Akademik Veri Yönetim Sistemi
Zeynep Kamil medical journal (Online), cilt.53, sa.4, ss.207-212, 2022 (TRDizin)
Objective: The aim of this study was to determine the reference ranges of second trimester nasal bone length (NBL), pre-nasal thickness (PT), and PT/NBL ratios of low- risk pregnant women in Turkish population. Material and Methods: Pregnant women of 16–28th gestational age who underwent ultrasonographic fetal screening between November 2021 and June 2022 were ret- rospectively analyzed. Fetuses with congenital malformations, high risk in antenatal screening tests, diagnosed with aneuploidy, and pregnant women of non-Turkish ethnic origin were excluded from the study. Fetuses were classified as ≤19+6 weeks, 20+0–20+6 weeks, 21+0–21+6 weeks, 22+0–22+6 weeks, 23+0–23+6 weeks, and ≥24+0 weeks. NBL, PT, and PT/NBL ratio was evaluated for each gestational age separately. Results: A total of 242 fetuses were included in the study. The mean NBL and mean PT increased with gestational age (6.42±0.65 at 20+0–20+6 weeks versus 7.65±0.79 at 23+0–23+6 weeks and 3.10±0.62 at 20+0–20+6 weeks vs. 3.55±0.63 at 23+0–23+6 weeks, respectively). Both NBL and PT were positively correlated with gestational age whereas the PT/NBL ratio was constant throughout the second trimester (PCC=0.81, p<0.001, PCC=0.56, p<0.001, and PCC=−0.07, p=0.255, respectively). The mean PT/NBL ratio in the second trimester was calculated as 0.46 (95% CI, 0.45–0.47, 5th p=0.35 and 95th p=0.62). Conclusion: The reference ranges for NBL, PT, and PT/NBL ratio may vary in differ- ent populations. Therefore, the use of population-specific nomograms may lead to higher success rates in Down syndrome screening.