About 50 percent of women over age 40 have fertility problems, the March of Dimes states. But even if a woman over 40 does get pregnant, she has a higher risk of complications during pregnancy compared to younger women. Many of the complications related to age in pregnancy can have life-threatening consequences for both mother and baby.
Chromosomal Abnormalities
As a woman ages, her eggs, which have been present since before birth, also age. Many of the eggs still left in the ovaries have chromosomal abnormalities. Because embryos with chromosomal abnormalities are often miscarried early in pregnancy, the miscarriage rate for a woman over 40 is higher than the miscarriage rate of a younger mom. The miscarriage rate for women over 40 is about 35 percent for diagnosed pregnancy, compared to 10 percent for women in their 20s.
Some babies with chromosomal abnormalities aren't miscarried; Down syndrome babies are the most notable example. The risk of having a baby with Down syndrome at age 40 is 1 in 100, compared to 1 in 1,250 at age 25, the March of Dimes states.
Gestational Diabetes
According to a December 2008 article published in "Diabetes Care," women over age 40 are six times more likely to develop gestational diabetes during pregnancy. As a result of the increased glucose absorbed during pregnancy, gestational diabetes can lead to producing large babies who have complications at the time of delivery and in the first few days of life.
Hypertension
High blood pressure during pregnancy, known as pregnancy-induced hypertension (PIH), and complications such as pre-eclampsia occur more frequently in women over 40, the American Heart Association reports. Because these conditions may threaten the lives of mothers, doctors often induce pregnancy early to protect maternal health.
Placenta Previa
Placenta previa, a condition wherein the placenta implants low on the uterine wall and may cover the opening of the uterus, the cervix, is three times more common in women over age 40. The placenta tears as the cervix begins to dilate and can lead to maternal and fetal hemorrhage.
Stillbirth
Women over 40 are two to three times more likely to have a stillbirth, or fetal demise. The risk of premature delivery and low-birth-weight babies is also higher in women over 40.
