Does Maternal Age Affect Pregnancy?

Increased maternal age can increase your child's risk of certain conditions

doctor with stethoscope on pregnant woman's belly
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A woman is born with all of the eggs she will ovulate with for the rest of her life. So if you're 30 when you conceive, then the egg you conceived with is also 30 years old. If you are 45 when you conceive, then the egg you conceive with is 45 years old. As eggs age, the more likely they are to have errors that can result in trisomies, including trisomy 21 (Down syndrome)

Does the Father’s Age Count?

Men can make sperm continuously throughout their life.

So a man may be 45, but the sperm he produces may only be a few weeks old. Since the sperm is young, it is thought to be protected from Down syndrome and other trisomies. While a father's age doesn’t contribute to the risk for chromosome abnormalities, men are not off the hook. Advanced paternal age negatively affects the likelihood of other genetic diseases such as achondroplasia (dwarfism), Marfan syndrome (a genetic syndrome characterized by tall stature and heart problems) and other autosomal dominant disorders. 

What is Advanced Maternal Age?

Advanced maternal age is a medical term that is used to describe pregnant women over the age of 35. This term is becoming less popular as an increasing number of older women are getting pregnant. While being of advanced maternal age can increase your chance of having a baby with Down syndrome, it also has other health implications.

Who Should have Prenatal Testing?

Prior to 2007, the American College of Obstetrics and Gynecologists (ACOG) used to recommend that all women over the age of 35 be offered prenatal diagnostic testing such as amniocentesis and chorionic villus sampling.

At the age of 35, your risk of having a baby with a chromosomal problem is about 1 in 200 and the risk to have a miscarriage from an amniocentesis was thought to be about 1 in 200. Since these rates were considered to be the same, 35 was picked as the recommended starting age for diagnostic testing.

In 2007, ACOG changed its guideline in which pregnant women should be offered prenatal testing. Two factors influenced this change in policy. First, they realized that the risk of miscarriage from amniocentesis was lower than 1 in 200 (around 1 in 500). The second was due to medical malpractice lawsuits against obstetricians in cases where younger women had babies with Down syndrome but weren’t offered prenatal testing.

It is important to note that the ACOG guidelines only refer to who should be offered prenatal testing. They do not recommend all women be tested, just that all women should be offered testing. It is up to you to decide whether or not you want prenatal testing and what type of testing, if any, is best for you and your pregnancy. 

There are many factors to take into account when making a decision about prenatal testing. Before going through with testing, it is important to understand your risk of having a baby with a chromosomal abnormality, as well as what you would do with any unexpected results.


Newberger, D., Down Syndrome: Prenatal Risk Assessment and Diagnosis. American Family Physician. 2001.

American College of Obstetricians and Gynecologists (ACOG). Your Pregnancy and Birth, 4th Edition. ACOG, Washington, DC, 2005.

Hook EB, Cross PK, Schreinemachers DM. Chromosomal abnormality rates at amniocentesis and in live-born infants. JAMA 1983;249(15):2034-38.