The risk of birth defects and miscarriage
increase with the increasing age of the mother. This usually happens because of
the abnormal division of the egg, which is called non
dis-junction. This eventually leads to unequal chromosomes at the end of the
division. Generally, a woman is considered to be at high risk for chromosomal
abnormalities when she is 35. Around 1 in 1,400 babies born to women in their
20's suffer from the ‘Down syndrome,’ and this increases to 1 in 350 or so in
women at 35.
There is evidence to show
that the risk of miscarriage (loss of a pregnancy before 20 weeks gestation) is
12% to 15% for 20-year-old pregnant mothers, which rises to nearly 25% for
women at 40 years. Older women are at a greater risk of miscarriages due to the
increased incidence of chromosomal abnormalities.