FETAL GROWTH-RETARDATION - ASSOCIATED MALFORMATIONS AND CHROMOSOMAL-ABNORMALITIES

OBJECTIVE: Our objective was to determine the incidence and pattern of chromosomal abnormalities in fetal growth retardation. STUDY DESIGN: Blood karyotyping was performed in 458 fetuses referred to us for further assessment of growth retardation at 17 to 39 weeks' gestation. RESULTS: The fetal karyotype was normal in 369 and abnormal in 89 (19%) of the cases. The most common chromosomal defect in the group referred at <26 weeks' gestation was triploidy; in those referred at greater-than-or-equal-to 26 weeks, it was trisomy 18. The incidence of fetal autosomal chromosome aberrations increased, whereas the incidence of triploidy did not change, with maternal age. Ninety-six percent of chromosomally abnormal fetuses had multisystem fetal defects that were characteristic of the different types of chromosomal abnormalities. Compared with those fetuses with a normal karyotype, the chromosomally abnormal group had a higher mean head circumference/abdominal circumference ratio, a higher incidence of normal or increased amniotic fluid volume, and normal waveforms from the uterine or umbilical arteries or both. CONCLUSION: The findings of the different types of chromosomal abnormalities and their ultrasonographically detectable phenotypic expression provide the background for prospective studies to determine the incidence of chromosomal abnormalities in unselected populations of small-for-gestational-age fetuses.