Karyotype analysis of umbilical blood in 15 500 newborns

Objective To study the incidence of chromosomal abnormalities in the umbilical cord blood, and analyze the number and structure and chromosome poly-morphism of the cord blood. Methods Umbilical cord blood was collected for lymphocyte culture, conventional G-banding and karyotype analysis. Results 15 500 cases of umbilical cord blood samples were detected, of which 314 cases were abnormal karyotypes, the rate was 2.03%.Chromosomal inversions of children were 220, the percentage in population was 1.42%, the constituent ratio was 70.10%.Chromosomal translocations samples were 41, the percentage in population was 0.26%, the constituent ratio was 13.00%.Chromosome-derived samples were 14, the percentage in population was 0.09%, the constituent ratio was 4.51%.Children with 21-Down Syndrome samples were 12, the percentage in population was 0.08%, the constituent ratio was 3.80%.Children with displaced robertson were 11, the percentage in population was 0.08%, the constituent ratio was 3.50%.In sex chromosome abnormalities, 47, XXX were 5, 47, XXY were 7, 45, X were 4, the percentage in population was 0.10%, the constituent ratio was 5.10%.Children with chromosomal polymorphism were 317, the percentage in population was 2.04%.Compared with the other groups, the chromosomal inversions group′ proportion and constituent ratio were significantly different (χ2=11.53, 15.98; P 0.05), the incidence of abnormal natural of each group was closer. Conclusions Karyotype analysis of neonatal umbilical cord blood is a very useful to the insufficient prenatal diagnosis, and important for secondary prevention, fertility and clinical guidlines. Key words: Infant, newborn; Fetal blood; Karyotyping; Chromosome aberrations