New York, New York -
(NBC News) A new government report finds that since the year 2000, the rate of women having their first babies after 35 has risen 24-percent, and 35-percent for women over 40.
But as women age, their chances of getting and staying pregnant decline.
"For much older mothers over 40, we start thinking about things like placental insufficiency, and the placenta just kind of wears out at the end of the pregnancy," says obstetrician Dr. Mark Bland of Novant Health.
Dr. Bland sees quite a few of these "older moms", who often must undergo additional genetic testing.
The risk for chromosomal problems increases with the mothers' age.
But Dr. Bland says these women are also more likely to have involved partners, exercise and eat well, and be well educated about the path to parenthood.
"So they're coming into pregnancy in good health and having planned it as opposed to the unplanned pregnancy," said Bland.