Chromosomes can be checked anytime after the child is born. Blood can be drawn for a chromosome test at any time after a child is born if you want it. Chromosome testing is usually done by drawing heel blood after a child is born, and there is no specified time for the test. If there is a suspicion that the child may have a chromosomal disorder, the test can be performed as early as possible and intervention can begin early. If both husband and wife have a clear history of chromosomal abnormalities, or if a child with chromosomal abnormalities or multiple malformations has been born in the past, and the pregnant woman belongs to the advanced maternal age, amniocentesis can be performed directly at about 16 weeks of pregnancy, through the examination of fetal decidualized cells in the amniotic fluid, so as to determine whether there are chromosomal abnormalities in the fetus, and to achieve eugenic sterilization. Consult your physician for more information.