Which factor is associated with a higher risk of conceiving a child with a genetic abnormality?

Maternal age over 35 years is a well-established risk factor for conceiving a child with a genetic abnormality. As women age, particularly starting at 35, the risk of chromosomal abnormalities, such as Down syndrome, increases significantly. This is mainly due to the aging of a woman's eggs, which can lead to incorrect chromosome division during meiosis. The likelihood of aneuploidy (an abnormal number of chromosomes) is higher in older eggs, which directly affects the genetic health of the embryo.

While other factors, such as maternal obesity and paternal health conditions like heart disease, can influence pregnancy outcomes, they do not have the same level of direct impact on the probability of chromosomal or genetic abnormalities in the fetus as maternal age does. Previous cesarean delivery relates more to obstetric risks and complications than to genetic risks. Therefore, maternal age is the most significant factor among the choices provided regarding the risk of genetic abnormalities.