What is a significant risk factor for Down syndrome?

Maternal age older than 35 years is recognized as a significant risk factor for Down syndrome. This association arises from the increased likelihood of chromosomal abnormalities occurring in oocytes as women age. Specifically, the risk of trisomy 21, which causes Down syndrome, increases with maternal age due to factors such as the potential for nondisjunction during meiosis, which is the process that forms eggs and sperm.

As women age, the quality and integrity of their eggs may decline, leading to a higher probability of errors during cell division. This correlation is well-documented in medical literature and is why prenatal screening for Down syndrome often recommends heightened scrutiny for women over the age of 35. Subsequently, the age-related risk becomes a critical consideration in genetics counseling and prenatal care, guiding healthcare providers in assessing potential risks and discussing options with expectant mothers.