About 10 percent of all pregnancies occur in women 35 or older. The age of 35 being defined as "advanced maternal age" was created to describe when the risk of a having a fetus with Down syndrome surpasses the risk of a miscarriage from an amniocentesis, an invasive procedure that screens for the abnormalities in a fetus.

A 35-year-old woman has a 1 in 375 risk of her baby having Down syndrome. Fertility rates are also lower and miscarriage rates are higher in women 35 and older. In general, there is a higher risk of pregnancy complications in women over 35, such as hypertension, diabetes, preterm delivery, multiple births, and fetal abnormalities.

There are no specific things that can be done during pregnancy to prevent complications from happening, only increased surveillance in detecting them. That is why it is important to have good prenatal care and to follow up with your doctor regularly.

There are several prenatal screening options available to women. Regardless of age, all women should be offered prenatal screening prior to 20 weeks. There are blood tests that can be done during your first and second trimester that can detect chromosomal abnormalities. A second trimester ultrasound can further detect any abnormalities.

Despite the increased risks of pregnancy, plenty of women age 35 and older have uncomplicated, healthy pregnancies.