Answer:
Late twenties
Step-by-step explanation:
A woman's fertility decreases as she ages. Women are born with all their egg cells, and as they age, the eggs' quality decreases, and so does the fertility. Women reach the peak of their fertility in their late twenties. After that, it starts to decline. It's estimated that between the age of 31 and 35 the chances of spontaneously conceiving decrease by about 3% per year. By age 40, these chances are lower than 5%. In cases of pregnancy at this age, due to poor quality of the egg cells, increased risk of miscarriage and chromosomal abnormalities is present.