What is advanced maternal age?

Advanced maternal age traditionally defines pregnancy where a woman is going to deliver at 35 or older. 

“It has been given lots of fun names in the past, including geriatric pregnancy or elderly pregnancy,” says Dr. Blenda Yun, OB-GYN at Mayo Clinic Health System in Eau Claire, Wisconsin.

Yun says the terminology is quite outdated, but comes from research that shows that women who are 35 and older are at a higher risk of enduring pregnancy complications.

Despite that, there is a trend in delaying pregnancy. According to the American College of Obstetricians and Gynecologists, about 20% of all pregnancies in the U.S.—and 11% of all first pregnancies—are in women over the age of 35. Women tend to delay starting families for many reasons, including waiting for financial stability, finishing an education or securing a work role, environmental concerns, or even deciding if being a parent is something that matters to them.

In fact, Pew Research shows that for most highly-educated women, motherhood begins in their 30s, if it happens at all. Among mothers with a bachelor’s degree, 40% were past their 20s when they had their first child, and 14% were at least 35. Also, one-fifth of moms with at least a master’s degree didn’t have kids until 35 at the earliest.

What are the risks of pregnancy at 35 or older?

As we age, we run the risk of developing chronic health conditions, like high blood pressure, obesity, or diabetes, says Yun. This is true for anyone, regardless of whether they are pregnant or not. But coupling these risks with an advanced maternal age can lead to potential complications, including:

• Gestational diabetes
• Cesarean delivery
• Preterm birth
• Miscarriage and stillbirth
• Multiple gestations (twins), especially in women over 40
• Hypertensive disorders including preeclampsia, especially in women over 40

Even if you don’t have any of the aforementioned health conditions, age can also play a factor into your pregnancy. As age goes up, egg quality goes down, according to the Cleveland Clinic. Older eggs have a higher chance of carrying chromosomal abnormalities. These are often screened for in the first trimester.

How do I lower the risk of complications?

While maternal age is an independent risk factor, your caution lights don’t necessarily need to be flashing if you’re near or beyond a certain age. “It’s not like there’s a magic shelf you fall off when you turn 35 and overnight your risks change. It’s more of a continuum,” Yun tells Fortune. 

Many women—most, actually—who are 35 and older have pregnancies with little-to-no complications. In fact, according to Johns Hopkins Medicine, only 8% of all pregnancies involve complications that, if left untreated, could harm the mother or baby. And it’s important to note that complications can arise, no matter the mother’s age or health status. “Just trying to be as healthy as possible before conceiving is important,” says Yun.

These are a few steps each mother—or future mother—can take to help lower the risk for pregnancy complications:

• If you have any pre-existing medical conditions, make sure to manage them. For instance, if you have diabetes, keep your blood sugar in range.
• Make sure all your preventative care is up to date.
• Prioritize a healthy diet.
• Exercise regularly. Aim for a level of activity that can be maintained throughout pregnancy.
• Take a prenatal vitamin that includes folic acid.
• Try to stay within a healthy weight range.
• Stop using tobacco in any form.
• Limit alcohol consumption while trying to conceive.

Yun encourages her patients who have reached advanced maternal age and are pregnant to preventatively take aspirin to reduce the risk of preeclampsia and other hypertensive disorders. Because of the increased risk of multiple gestations—especially when over the age of 40—ACOG recommends a first trimester ultrasound for dating purposes. Genetic screenings are suggested for all patients, regardless of age.

For patients specifically over 40, Yun says she also recommends tracking third trimester growth as there is an increased risk of extremities growing too small or too big. Antenatal testing, which is used to evaluate fetal wellbeing and placenta function, also starts around 34 weeks and occurs weekly, she says. Because of the increased risk of a stillbirth after 40 weeks, it is common for doctors to propose labor induction at 39 to 40 weeks.

“By doing recommended intervention, there is no reason for women to think they can’t go on to have a perfectly normal, healthy pregnancy. I don’t want people to feel limited by this cut-off that in hindsight is a little bit arbitrary,” says Yun.