Risks are much, much, much higher. Chromosome disorder in 40 year old mothers is 1 in 30. For 25 year olds it is 1 in 1250. So from .08% to 3.33%. Chance of miscarriage is 80% for a 40 year old mother. For a 35 year old, it is 20%.

https://www.webmd.com/baby/over-35-pregnant