Pp. Pandya et al., SCREENING FOR FETAL TRISOMIES BY MATERNAL AGE AND FETAL NUCHAL TRANSLUCENCY THICKNESS AT 10 TO 14 WEEKS OF GESTATION, British journal of obstetrics and gynaecology, 102(12), 1995, pp. 957-962
Objective To evaluate screening for chromosomal defects by a combinati
on of fetal nuchal translucency thickness and maternal age. Design A p
rospective multicentre screening study where fetal nuchal translucency
thickness was measured at 10 to 14 weeks of gestation. Subjects 20,80
4 women with singleton pregnancies screened at 10 to 14 weeks of gesta
tion from 1 September 1992 to 28 October 1994. Main outcome measures T
risomy 21 and other chromosomal defects identified by increased nuchal
translucency thickness and by a combination of nuchal translucency th
ickness and maternal age. Results In normal fetuses nuchal translucenc
y thickness increased significantly with crown-rump length. The nuchal
translucency was above the 95th centile in 77 % (66 of 86) of fetuses
with trisomy 21 and in 78 % (61 of 78) of those with other chromosoma
l defects. On the basis of the distribution of nuchal translucency mea
surements in normal fetuses and those with trisomy 21, a new method of
screening is proposed which involves assessment of individual risk ba
sed on the combination of fetal nuchal translucency, crown-rump length
and maternal age. The minimum risk was 1/100 in 4.9 % of the normal p
regnancies, in 80 % of those with trisomy 21 and in 77% of those with
other chromosomal defects. Conclusion Screening for fetal trisomy 21 c
an be carried out effectively during the first trimester of pregnancy.