ABNORMALITIES OF THE HEART AND GREAT-ARTERIES IN FIRST-TRIMESTER CHROMOSOMALLY ABNORMAL FETUSES

Pathological examination of the heart and great arteries was performed in 112 chromosomally abnormal fetuses after surgical termination of p regnancy at 11-16 weeks of gestation, The chromosomal abnormalities we re diagnosed by chorion villus sampling which was carried out because screening of the pregnancies by a combination of maternal age and feta l nuchal translucency thickness at 10-14 weeks of gestation identified them as being at increased risk, The group consisted of 60 fetuses wi th trisomy 21, 29 with trisomy 18, 17 with trisomy 13 and 6 with Ullri ch-Turner syndrome, The most common cardiac lesion seen in trisomy 21 fetuses was an atrioventricular or ventricular septal defect, Trisomy 18 was associated with ventricular septal defects and/or poly-valvular abnormalities, In trisomy 13, there were atrioventricular or ventricu lar septal defects, valvular abnormalities, and either narrowing of th e isthmus or truncus arteriosus, Ullrich-Turner syndrome was associate d with severe narrowing of the whole aortic arch, In all four groups o f chromosomally abnormal fetuses, the aortic isthmus was significantly narrower than in normal fetuses and the degree of narrowing was signi ficantly greater in fetuses with high nuchal translucency thickness, I t is postulated that narrowing of the aortic isthmus may be the basis of increased nuchal translucency thickness in all four chromosomal abn ormalities. (C) 1997 Wiley-Liss, Inc.