An excerpt from Understanding High-Risk Pregnancy: A Patient’s Guide to Prenatal Complications.
If you are 35 or older and either pregnant or thinking about having a baby, you are not alone. The average age for women having babies in this country and around the developed world has increased significantly over the past two decades, and the percentage of women having children after age 35 has increased as well. The teenage pregnancy rate in the United States has dropped dramatically, and the percentage of births to women over 35 has increased forty percent since 2000. Even births to women in their forties and fifties has been increasing, often with the assistance of fertility treatments. Presumably this increase in maternal age is related to more women entering the work force and having careers, as well as more consistent use of effective birth control methods. Yet pregnancy after age 35 has been thought to be riskier, and sometimes referred to as advanced maternal age.
Studies have long shown that pregnancy in older women is associated with increased risks of complications for both the mother and the fetus. Mothers have a higher incidence of developing preeclampsia, gestational diabetes, and miscarriage, and rates of cesarean are also increased. It is not surprising that as we get older, we are more likely to have acquired a diagnosis of a chronic condition, such as diabetes or hypertension, than when we were in our twenties. Being overweight or obese is also more common with aging. These conditions are a major reason why pregnancy complications are more common among women over 35. One study found that compared to women in their twenties, the severe complication rate for women aged 35 to 39 was forty percent higher, for women aged 40 to 44 was almost double, and for women 45 and older it was more than triple. For the fetus born of a woman over 35, there are higher rates of preterm birth, growth restriction, and stillbirth, primarily after age 40. Some fetal complications are related to underlying maternal conditions, but the increase in complications is also seen in healthy women. Rates of chromosomal abnormalities, such as Down syndrome, also increase with maternal age. Women over the age of 35 at the time of delivery should be aware of these concerns. Nonetheless, you need to remember that although these risks are elevated relative to younger mothers, most women aged 35 and older are still able to have healthy babies without major complications.
Management of pregnancy at age 35 and older
The pregnancy care for women aged 35 and above is not too different from the care provided for younger women. If a chronic condition or illness is present, the recommendations are as outlined for that condition later in this book. For women without an underlying condition, the options for genetic testing should be made available. To reduce the risk of preeclampsia, a single, daily, low-dose aspirin tablet is recommended beginning between twelve to sixteen weeks until delivery. Ultrasounds should be performed to look for birth defects and to assess fetal growth. And due to the higher rate of stillbirth at age 40 and after, initiating weekly fetal surveillance in the third trimester with either a non-stress test (NST) or biophysical profile (BPP), and proceeding with delivery by the mother’s due date is frequently recommended.
While it should be recognized that some of the risks of pregnancy are increased with advancing maternal age, you should also recognize that the odds of a successful pregnancy outcome are still very much in your favor. Most women who are in good health entering pregnancy, and those with an underlying medical condition which is well controlled, have a favorable prognosis. With the appropriate care and some extra testing, women beyond the age of 35 are most likely going to have a healthy child without a major risk to their own health.
Alan M. Peaceman is an obstetrician-gynecologist.
