What is considered advanced maternal age?

When a woman gets pregnant past the age of 35, she is considered to be of advanced maternal age. There are several reasons why a pregnancy beyond that age could be an issue. It's more difficult to get pregnant as a woman gets older, it may take longer to get pregnant, and there are more pregnancy complications such as miscarriages, diabetes, and hypertension.

As a woman ages, her egg stores are also lower and the remaining eggs may not be as healthy and viable as they were when she was in her 20s. Doctors use a woman's age of 35 and older as one of the key points in determining whether or not a woman needs advanced medical care during pregnancy due to a potential increase in pregnancy risk. Most women over the age of 35 do not have complicated pregnancies, but doctors remain on high alert throughout the pregnancy, just in case.

Difficulties Getting Pregnant

At 35 years of age and beyond, it's more difficult to get pregnant as a woman gets older, and it may also take longer to get pregnant. This is mostly related to a woman's eggs getting older and the quality of her eggs diminishing. She is less likely to ovulate, and her eggs are also less likely to get fertilized and implant.

Increased Risk of Down Syndrome

One of the most notable pregnancy risks for women of advanced maternal age is Down Syndrome. Down Syndrome is a chromosomal defect thought to be associated with aging eggs. By the age of 40, about one in 100 women are at risk of having an infant with Down Syndrome. Past the age of 40, the risk of Down Syndrome increases exponentially. By the advanced maternal age of 49, about one in 12 women are at risk. Doctors will often request amniocentesis or chorionic villus sampling (CVS) to determine the risk of Down Syndrome in the fetus.

Increased Risk of Preterm Birth

Several studies have shown a relationship between preterm birth (PTB) and advanced maternal age. In a large retrospective, Canadian study women over 40 years of age had increased risk factors for PTB such as chronic hypertension, use of assisted reproductive technology (ART), pre-gestational and gestational diabetes, invasive procedures during pregnancy, and placenta previa. Their risk of PTB was 20 percent higher when compared to those age 30-34 years. 

Increased Risk of Having Fraternal Twins

With advanced maternal age comes an increased chance of fraternal twin pregnancy. In addition to age, the number of pregnancies also comes into play. If a woman aged 35 becomes pregnant and she has four pregnancies prior to the current pregnancy, she is three times more likely to conceive fraternal twins.

Other Health Risks With Advanced Maternal Age

As women age, they are more likely to suffer from diseases and conditions associated with aging, such as diabetes, hypertension, and arthritis. Some of these conditions and the age of the body, in general, may increase the risk of gestational diabetes, pregnancy-induced hypertension, and premature labor.

Testing and Risk of Miscarriage

The two most common invasive tests suggested in women of advanced maternal age are CVS and amniocentesis. Both tests increase the risk of miscarriage; in both women of advanced maternal age and women of normal maternal age, but the risk is less than one percent. The tests are completely optional and are not required for obstetric care, so you must weigh the risks of CVS and amniocentesis with the benefits of early detection of potential fetal health conditions.

Fortunately, there are noninvasive tests available that can provide information on risks of the fetus having certain chromosomal conditions. These tests are cell-free DNA, a blood test done as early as 10 weeks, and nuchal translucency screening.

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