Final answer:
The risk of having a baby with a chromosomal abnormality such as Down syndrome increases dramatically for women aged 35 and older. Advanced maternal age also affects the success rates of pregnancies via Assisted Reproductive Technologies and is associated with higher rates of various complications and malformations.
Step-by-step explanation:
The risk of having a child with a chromosomal abnormality, such as Down syndrome (also known as trisomy 21), increases dramatically for women as they age. According to data from the American Family Physician (August 15, 2000), the incidence of having a fetus with trisomy 21 becomes significantly higher among women age 35 and older. This pattern is apparent in a variety of genetic conditions that can affect the fetus, not just Down syndrome.
Furthermore, as women age, their chances of successful pregnancy through Assisted Reproductive Technologies (ART) also decline. Studies have shown that ART has around a 40 percent chance of leading to a live birth in women under the age of 35, but those chances decrease to about 20 percent after the age of 35. While some birth defects are found to be associated with ART, it's believed that the age of the parents plays a significant role in these outcomes.
In general, advanced maternal age is also associated with other complications in pregnancy and childbirth. The global average of all live births complicated by malformation is around 6 percent, with genetic factors being the principal cause. With increased maternal age, the risks to the central nervous and skeletal systems of the fetus are more pronounced.