Many of today's women are delaying childbearing until later in life for a variety of reasons, including career choices, financial status, late marriage, and remarriage. In addition, successful treatment of previously infertile women over 40 is on the rise. In fact, reports indicate successful pregnancies in women over age 60!

While such extreme cases raise complex social and ethical issues (not to mention medical issues), the fact of the matter is that more women over age 40 are choosing to start a new family or add to their present one.

Of course, for some women, it's not a matter of choice. Unplanned pregnancies account for a large proportion of babies born to women over age 40. What risks do these women incur? Let's examine the facts regarding pregnancy in this age group and strategies to reduce the risks.

The Facts

Standard medical teaching indicates a higher risk for pregnancy complications in women over the age of 35. These complications can be categorized as follows:

  • Medical illnesses affecting the mother and fetus
  • Genetic abnormalities and birth defects
  • Pregnancy loss
  • Complications of labor and delivery

As age increases beyond age 35, so does each of these risks. Nevertheless, proper preparation before pregnancy and early prenatal care can help assure the best outcome.

There’s nothing magical about the risk possibilities at specific ages, such as 35 or 40. Risks of genetic abnormalities and miscarriage rise progressively throughout a person's reproductive years. By accumulating years, it is more likely that a mom-to-be will have acquired a medical illness. However, this is a population statistic (ie, a general trend); many individual women over 40 are very healthy and have much less risk than certain much younger women.

Maternal and Child Illnesses

Certain medical conditions occur more frequently in pregnant women over 40, including diabetes , high blood pressure , and thyroid disorders . Fortunately, these conditions can be diagnosed and controlled prior to pregnancy, and many of the medications used to treat these disorders can be safely used during pregnancy. If you currently take medication and you are planning a pregnancy, talk to your doctor. A change in medication or an adjustment of dosage may be necessary.

If not properly treated, maternal illnesses can adversely affect the fetus. Uncontrolled high blood pressure can restrict fetal growth and, in severe cases, can result in stillbirth. Undiagnosed diabetes can carry with it a higher risk of birth defects and stillbirth; and, poor blood sugar control during pregnancy can result in abnormal fetal growth. Early prenatal care and judicious use of medication can lower these risks significantly.

Genetic Defects

It is an unfortunate but incontrovertible fact that as a woman ages, a higher proportion of her aging eggs contain chromosomal abnormalities. At the present time, some infertility centers have the technology to weed out these abnormal eggs, but for the majority of women who become pregnant after the age of 40, the risk of a genetic defect increases based on age.

While the general population of childbearing women has a 3% chance of delivering a child with a birth defect, after age 40 this risk is between 6% and 8%. The likelihood of having a baby with Down's syndrome is approximately 1 in 365 at the age of 35. This number increases to 1 in 100 by the age of 40 and up to 1 in 40 at the age of 45.

Pregnancy Loss

Pregnancy loss also increases with advancing age. Approximately 60% of early (first trimester) miscarriages are due to genetic abnormalities of the fetus. Overall, pregnant women experience miscarriage 15% of the time. After age 40, this incidence nearly doubles. There is also a moderate increase in stillbirths after age 40 due to a combination of medical complications affecting pregnancy and lethal birth defects.

Complications of Labor and Delivery

Complications of labor and delivery that are seen more frequently in women over age 40 include:

  • Premature labor
  • Premature separation of the placenta resulting in hemorrhage
  • Placenta previa (abnormal placement of the placenta over the opening of the cervix)
  • Meconium-stained amniotic fluid (fetal waste in the amniotic fluid which can be harmful if breathed in by the baby at birth)
  • Postpartum hemorrhage
  • Malpresentations (breech or other positions other than head down)

As a result, the rate of Cesarean section is considerably higher in this age group.

Lowering the Risks

Although the risks associated with pregnancy after 40 are numerous and sometimes unavoidable, there are several strategies that women over 40 can use to reduce these risks.

See Your Doctor

First and foremost, make an appointment to see your doctor before you get pregnant. This "preconception" visit will give your doctor the opportunity to diagnose and treat any disorders that might otherwise go undetected prior to the initial prenatal visit.

A thorough evaluation prior to pregnancy will allow your doctor to give you an idea of your individual risk. There may be cases in which pregnancy will be ill-advised. However, for the majority of women over age 40, early prenatal care and good health habits will result in a healthy baby and a happy mother.

Get Healthy

The idea is to be as healthy as you can before you get pregnant. Here are some tips:

  • If you smoke, quit .
  • Avoid alcohol . —Alcohol can increase the risk of certain birth defects and interfere with proper fetal growth.
  • Avoid caffeine . —Even moderate caffeine intake might increase your risk of miscarriage (although this remains controversial).
  • Eat a well-balanced diet .—This means one that is rich in fruits, vegetables, whole grains, and low-fat dairy and other protein sources. If you need help, ask your doctor for a referral to a registered dietitian.
  • Start a prenatal vitamin prior to pregnancy and stick with it.—The folic acid in prenatal vitamins is known to reduce certain birth defects and the iron supplement will combat anemia.
  • Exercise regularly , but moderately.—Exercise is good for toning muscles and limbering joints, thereby decreasing the normal aches and pains associated with pregnancy. If you don't exercise already, check with your doctor before starting an exercise program. Obesity is a major risk factor in pregnancy at any age.

Get Tested

If you are concerned about the risk of genetic defects, especially if you have a family history, ask your doctor about tests that can help identify these types of problems. Blood tests are available to screen for some genetic disorders either before or during pregnancy. A "triple screen" or "quad screen" blood test may be obtained to evaluate the risk of neural tube defects and Down syndrome .

Genetic amniocentesis (or chorionic villus sampling) is offered to women after the age of 35. Amniocentesis is usually done in the third or fourth month of pregnancy and involves removal of amniotic fluid from the womb for genetic testing. There is a minimal (0.25%) risk of miscarriage associated with this test. This risk is outweighed however by the slightly larger risk of having an undetected abnormality.

Chorionic villus sampling can be done earlier in pregnancy and involves the removal of a minute amount of placental tissue, which can then be tested for genetic abnormalities. The risk of miscarriage may be as high as 0.75-1.0% with this test. Discuss the risks and benefits of these tests with your doctor early on so that you will have ample time to make an informed decision.