Second Trimester Fetal Nasal Bone Length Measurement: A Single Center Study and National Data Review

Objective: To evaluate second trimester fetal nasal length measurement results in healthy singleton pregnancies in Turkey. Material and Methods: We analyzed the nasal bone lengths within 19-24 weeks in 661 pregnancies in our hospital. All pregnant women with a single healthy fetus who applied to our perinatology outpatient clinic for detailed obstetric ultrasonography were included in the study. All measurements were performed by the same clinician during routine mid-trimester ultrasound scan. Only the patients who were considered healthy by the examining pediatrician were included in the study. The parents of all fetuses are of Turkish ethnicity. Pearson correlation, regression analysis and P value were calculated between gestational week and nasal bone length. Results: Mean nasal length measurement was 6,21 ± 0,08; 6,66 ± 0,05; 6,88 ±0,05; 7,13 ± 0,08; 7,77 ± 0,11 and 8,33 ± 0,25 mm from 19 to 24 week of pregnancy, respectively. A significant positive correlation was observed between gestational week and nasal bone length. Normal values of nasal bone length measuremens are identified for each gestational weeks acoording to our data and previous 5 studies. Conclusion: In this study, we presented the data of our own center and the results obtained from other studies conducted in our country show significant differences. We are of the opinion that studies conducted by different researchers in different regions remain insufficient to reflect the nomogram of Turkish ethnic origin. For this purpose, multicenter studies are needed to cover the whole society.