First-trimester nuchal translucency measurement and echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18.
BACKGROUND
Trisomy 18, the second most common autosomal trisomy, has the highest incidence of congenital heart disease of all chromosomal abnormalities. This study assessed the use of nuchal translucency (NT) measurement and fetal echocardiography at 16 to 18 weeks of gestation in prenatal detection for trisomy 18.


METHODS
Screening for chromosomal aneuploidy using fetal NT measurement was performed at 10 to 14 weeks of gestation. Detailed fetal echocardiography was performed at 16 to 18 weeks of gestation immediately before genetic amniocentesis for fetal karyotyping in singleton pregnancies with increased fetal NT thickness.


RESULTS
Of the 3151 singleton pregnancies included in our study, 171 cases (5.4%) of increased (> or =3.0 mm) NT were noted. Fetal chromosomal abnormalities were identified in 22 (12.9%) of these pregnancies, including 9 with trisomy 21, 5 with trisomy 18, 4 with 45,X and 4 with unbalanced structural abnormalities. Major defects of the heart and the great arteries were identified in 13 (7.6%) of these pregnancies with increased NT. These included eight pregnancies that also had the diagnosis of chromosomal aneuploidy. Among the 22 fetuses with confirmed aneuploidy, all 5 fetuses with trisomy 18, 1 of the 4 fetuses with 45,X and 2 of the 9 fetuses with trisomy 21 had increased fetal NT thickness associated with abnormal fetal echocardiography findings.


CONCLUSIONS
Screening for Down syndrome and cardiac defects using first-trimester fetal NT measurement in combination with fetal echocardiography at 16 to 18 weeks of gestation is a feasible and sensitive procedure for the prenatal detection of trisomy 18.
Cheng
Po-Jen
PJ
Department of Obstetrics and Gynecology, Chang Gung Memorial Hospital, 5 Fu-Shin Street, Kweishan, Taoyuan, Taipei, 333 Taiwan, ROC. pjcheng@cgmh.org.tw
Liu
Ching-Ming
CM
Chueh
Ho-Yen
HY
Lin
Chien-Ming
CM
Soong
Yung-Kwei
YK
D000293:Adolescent; D000328:Adult; D002869:Chromosome Aberrations; D002887:Chromosomes, Human, Pair 18; D004452:Echocardiography; D005260:Female; D005865:Gestational Age; D006801:Humans; D007621:Karyotyping; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging / Q000196:embryology*; D011247:Pregnancy; D011296:Prenatal Diagnosis; D014314:Trisomy; D016216:Ultrasonography, Prenatal