Purpose
Nuchal skin-fold thickness (NFT) measurement in the second-trimester has been widely used as a sonographic screening test for Down syndrome.
It was first described by Benacerraf et al.
in 1985.
The upper limit of normal NFT has been reported to be 6 mm in many studies.
The aim of our study was to find out whether fetal gender affects second trimester NFT measurements in normal fetuses.
Methods and Materials
This is a prospective study which was held in a single university hospital between November 2009 and April 2010.
Detailed second-trimester US examinations were performed in 419 women between 18–24 weeks of gestation.
All US examinations were performed by a radiologist who is experienced in fetal imaging.
Fetuses with enlarged NFT measurements,
major congenital anomalies,
and patients with multiple gestations were excluded from the study.
Pregnancy outcome was obtained from the hospital files.
The fetuses with normal fetal US findings that have normal physical examinations...
Results
NFT values ranged between 3–6 mm and 2.3–6 mm,
in male and female fetuses,
respectively.
Mean NFT values were 4.61±0.75 mm and 4.34±0.78 mm for male and female fetuses,
respectively.
Median NFT value for male fetuses was 4.6 mm,
whereas it was 4.4 mm for females.
Using Mann Whitney test,
statistically significant difference was denoted between male and female groups’ NFT measurements (P=0.001,
P < 0.05 was considered as statistically significant).
Conclusion
In conclusion,
ultrasonographic detection of Down syndrome can be challenging.
To assess the fetal risk for Down syndrome,
maternal serum AFP levels and ultrasonographic parameters are used in combination.
NFT is generally accepted as the single best ultrasonographic parameter for detecting Down syndrome.
Moreover,
ultrasonographic detection of Down syndrome can be improved by using a combination of gender-specific biometric parameters.
In our opinion,
to reduce the false-positive risk assessment rate in male fetuses,
one should always keep the effect of gender on NFT measurements in...
References
Benacerraf BR,
Barss VA,
Laboda LA.
A sonographic sign for the detection in the second trimester of the fetus with Down’s syndrome.
Am J Obstet Gynecol 1985;151:1078–1079.
Benacerraf BR,
Frigoletto FD,
Laboda LA.
Sonographic diagnosis of Down syndrome in the second trimester.
Am J Obstet Gynecol 1985;153:49–52.
Perrella R,
Duerinckx AJ,
Grant EG,
et al.
Second-trimester sonographic diagnosis of Down syndrome: role of femur-length shortening and nuchal-fold thickening.
AJR Am J Roentgenol 1988;151:981–985.
Nyberg DA,
Resta RG,
Luthy DA,
et al.
Prenatal sonographic findings of...