High Quality Content by WIKIPEDIA articles! Age and female fertility encompasses a woman`s fertility as affected by her age. A woman`s fertility peaks in the early and mid twenties, after which it starts to decline, with advanced maternal age causing an increased risk of female infertility. This is popularly referred to as a woman`s "biological clock". Another risk that increases significantly into the mother`s midlife is chromosomal abnormalities, to include Down syndrome.