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A Thai reference for normal fetal nasal bone length at 11-13(+6) weeks gestation
N Pruksanusak1, C Suwanrath, O Kor-anantakul
1Department of Obstetrics and Gynecology, Faculty of Medicine, Prince of Songkla University, Hat Yai, Thailand.
Gynecologic and Obstetric Investigation
|December 3, 2011
Summary
This study established a Thai reference for fetal nasal bone length (NBL) between 11-13(+6) weeks gestation. Thai fetal NBL measurements were found to be shorter than in some populations but similar to others.
Area of Science:
- Prenatal diagnosis
- Fetal biometry
- Medical imaging
Background:
- Accurate fetal biometry is crucial for assessing gestational age and detecting chromosomal abnormalities.
- Nasal bone length (NBL) is a significant marker in first-trimester screening for Down syndrome.
- Establishing ethnic-specific reference ranges improves the accuracy of prenatal screening.
Purpose of the Study:
- To establish a normative reference range for fetal nasal bone length (NBL) in a Thai population.
- To provide a reliable dataset for Thai pregnant women undergoing first-trimester screening.
- To compare Thai fetal NBL with existing data from other ethnic groups.
Main Methods:
- Sonographic measurement of fetal nasal bone length (NBL) in pregnant women.
- Gestational age assessment between 11 and 13(+6) weeks.
- Postnatal examination of neonates with normal karyotypes to confirm absence of congenital abnormalities.
Main Results:
- A total of 255 pregnant women were recruited; 208 were included in the final analysis.
- The mean NBL was 1.79 ± 0.33 mm, significantly increasing with crown-rump length (CRL) and gestational age (p < 0.001).
- The derived equation for NBL in euploid fetuses was NBL (mm) = (0.030 × CRL (mm)) - 0.016.
Conclusions:
- Fetal NBL in Thai fetuses at 11-13(+6) weeks gestation is, on average, shorter than in Caucasian, African-American, and Chinese populations.
- Thai fetal NBL measurements are comparable to those reported in Korean and Latin-American populations.
- These findings highlight the importance of ethnic-specific reference ranges for fetal nasal bone length in prenatal screening.
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