Which maternal age is associated with an increased risk for chromosomal defects?

Which maternal age is associated with an increased risk for chromosomal defects?

• A. Under 20
• B. 20-35
• C. Over 35
• D. No effect by age

Answer: (C)

Advanced maternal age increases the risk of chromosomal abnormalities because the machinery that ensures proper chromosome separation during egg division becomes less reliable as age rises. Eggs are formed before birth and can remain arrested in meiosis for many years; with aging, nondisjunction events become more likely, leading to embryos with an extra or missing chromosome. The risk of conditions like Down syndrome rises notably after 35 and climbs further by 40 and beyond (roughly higher than the baseline in younger women). Younger mothers have a much lower risk, and there is no increased risk attributed to age at ages under 20.

Advanced maternal age increases the risk of chromosomal abnormalities because the machinery that ensures proper chromosome separation during egg division becomes less reliable as age rises. Eggs are formed before birth and can remain arrested in meiosis for many years; with aging, nondisjunction events become more likely, leading to embryos with an extra or missing chromosome. The risk of conditions like Down syndrome rises notably after 35 and climbs further by 40 and beyond (roughly higher than the baseline in younger women). Younger mothers have a much lower risk, and there is no increased risk attributed to age at ages under 20.