Correlation between rare chromosomal abnormalities and prenatal ultrasound findings

Our objective was to examine ultrasound findings with outcomes in cases of rare chromosomal abnormalities diagnosed during pregnancy. Results of cytogenetic studies obtained from amniocenteses and chorionic villus samplings (CVS) from 1994-2000 were reviewed. Only those examples of rare chromosomal abnormalities with little information on the associated outcome were included. Cases of autosomal trisomy (13, 18, and 21), sex chromosome aneuploidy, and reciprocal or Robertsonian translocations were excluded. Ultrasound findings and outcomes were reviewed. In all, 8,642 procedures of amniocenteses and 557 of CVS were performed; 21 cases met the inclusion criteria. Parental karyotypes were obtained for 19 couples and the karyotypic abnormalities were de novo in 13. Abnormal ultrasound findings were present in 14 pregnancies, with the following outcomes: seven underwent dilatation and evacuation (D&E), with abnormal findings in two (although examination was limited by fragmentation); one medical termination with micrognathia and low-set ears; one fetal demise; one neonatal demise; three surviving neonates with abnormalities (one each with congenital kyphosis, hydronephrosis, and hypotonia), and one newborn was normal. There were seven patients without abnormal ultrasound findings with the following outcomes: three underwent D&E, with abnormal findings in two, one child with a colobomatous optic nerve, and two apparently normal infants. Follow-up was not available in one patient. We conclude that when rare karyotypes and ultrasound abnormalities are present, poor outcomes are likely. Even with normal ultrasound findings, abnormalities may be present. These data may assist in counseling patients when testing reveals such chromosomal abnormalities.