What Are The Risks Of Getting Pregnant After 35 Years?

The many stresses in life have over the years ushered in a trend of older parenthood. More and more women in their 30s are today having babies as compared to women in their 20s. Pregnancies in women over the age of 35 are typically referred to as geriatric pregnancies. Medically, any pregnancy that occurs in a woman who is over the age of 35 is termed as a geriatric pregnancy. According to recent data from the US Centers for Disease Control and Prevention (CDC), in 2016, for the very first time in almost three decades, the birth rates in women between the ages of 30 to 34 surpassed that in women aged 25 to 29 in the United States.¹

Another study by the CDC found that the average age that women are now having their first is at around 28 years, which has gone up from 26.4 years in 2015, and 26.3 years in 2014.² Health experts are often prone to focus on the average or mean maternal age because of the connection between birth outcomes and the age of the mother. Some of these outcomes include a higher rate of congenital disability and multiple births.

Studies have also reported that people are more likely to delay parenthood until they reach 35 or even older for various reasons. These reasons may include women wanting to pursue higher levels of education, taking time to establish their career, better and improved methods of contraception, cultural and social shifts that have left many women feeling they are not ready to have children, a lack of affordable childcare, low benefit levels, economic and housing uncertainties, rising unemployment, as well as inflexible workplace policies at many places.

One more reason why many women are choosing to get pregnant later in life could be due to more advanced fertility options, especially In Vitro Fertilization (IVF).³

Women who are over the age of 35 and are pregnant with their first baby are also known as being older mothers or being of advanced maternal age (AMA). They are also referred to as elderly primipara or elderly primigravida. While terms such as geriatric pregnancy, elderly, advanced age, and others have negative connotations for women who are just 35 years old, are there truly more risks involved in being over 35 years and pregnant? Let us take a look.

Does being pregnant after you turn 35 mean your risk goes up substantially? While women continue having perfectly healthy pregnancies throughout their 30s and well beyond it as well, but after reaching 35 years, there are some risks that become worth considering.⁴ while these risks do increase slightly after turning 35 years old, this does not mean though that these factors will affect everyone who is in their mid-thirties and older in the same way. Let us look at some of these risk factors.

As women age, the chances that they will become pregnant declines as the number of remaining eggs go down, and their quality also decreases. Fertility too declines in men as they age because of declining sperm motility and count, and semen volume. These are some age-related factors that, when combined, can make it more challenging for women to get pregnant.

A 1982 study published in the New England Journal of Medicine found that amongst women who underwent artificial insemination to get pregnant, 74 percent were under the age of 31 and were pregnant within one year. However, this percentage went down to 61 percent of women in the age range of 31 to 34 years, and it further declined to 54 percent of women who were 35 years and over.⁵

The risk of miscarriage goes up gradually as the mother ages. A 2000 study published in the BMJ found that the risk of miscarriage was around 8.9 percent for women who were aged 20 to 24 years, and it further went up to 74.7 percent for women aged 45 years or above.⁶ The declining quality of women’s eggs as they age is believed to be responsible for the higher chances of miscarriage.

There are certain genetic risks also to be considered. These genetic risks more commonly present in women who are aged 35 years and above.⁷ For example, the likelihood of having a baby with Down’s syndrome goes up exponentially with increasing maternal age.⁸

While the rate of having a baby with Down syndrome during the 10-week mark of pregnancy is just 1 in 1,064 at a maternal age of 25 years, it rises dramatically to 1 in 686 at maternal age 30 years, and 1 in 240 by the age of 35 years.9 By the time a mother reaches 40 years, the risk of Down syndrome increases to 1 in 53, and furthermore to 1 in 19 by the age of 45 years.

A 2015 study published in Nature Communications went ahead and investigated why women who become pregnant at an advanced age have a greater risk of giving birth to babies with congenital anomalies that are further characterized by abnormal chromosome numbers.¹⁰ The research team found that the genetic process of recombination was the likely cause for the increased risk of Down syndrome in older mothers.

What is recombination? Well, recombination is the process during which pairs of chromosomes exchange genetic materials before they separate. The research team further found that in older mothers, this process of recombination is less regulated, which is what leads to the abnormal chromosome numbers in the sex cells or in the larger chromosomal rearrangements.

Studies have found that stillbirth is more common to occur in older mothers than younger women. A review published in the Canadian Medical Association Journal discovered that stillbirth is about 1.2 to 2.23 times higher in older mothers.¹¹

Another study that looked at data from 385,120 pregnancies in the UK found that the rate of stillbirth was 4.7 per 1,000 for women who were aged 18 to 34. This rate went up to 6.1 per 1,000 in women in the ages of 35 to 40 years. It was 8.1 per 1,000 for women who were 40 years and over.¹²

Additionally, the rate of stillbirth is known to be higher in people who are having their first child and even higher in first-time mothers who are 35 years or older.¹³

Women who are 35 and older are usually recommended to be induced into labor as they start approaching their due date because of the high risk of having a stillbirth with gestational age. As per estimates, approximately 1 in 1,000 women under the age of 35 years will have a stillbirth during the 39 and 40 weeks of gestation. This is compared to 1.4 in 1,000 women in the ages of 35 to 39, and 2 in 1,000 women aged 40 and above.¹⁴

The exact reason why stillbirth rates go up with maternal age is still unclear.

A study that compared pregnancy complications in women aged 18 to 34 years, 35 to 40 years, and 40 years and above found that there was a small increase in most birth and pregnancy-related complications as the mother’s age increased.¹⁵

The research team found increases in the risk of placenta previa, gestational diabetes, emergency cesarean, breech positioning of the baby, preterm birth, postpartum hemorrhage, low birth weight, and high birth weight. Other studies have also found that the risk of maternal mortality also went up with age.¹⁶

Recently in 2017, a study published in the Journal of Physiology found out why women over the age of 35 are more likely to face birth and health complications.¹⁷ The research team from King’s College London conducted studies on mice to find that a mother’s age has an influence on the structure of the uterus.

A group of mice that represented women who were over 35 years old were found to have muscle contraction properties in the uterus that were impaired, had reduced numbers of mitochondria, and were less sensitive to oxytocin. All these factors indicated that the uterine muscles were not able to contract properly. Additionally, the researchers also found certain changes in progesterone signaling, which caused a delay in the process of labor. These important cellular and physiological changes were found to be directly associated with a mother’s age and resulted in labor dysfunction. Since the timing of delivery as well as the progress of labor is directly linked with maternal age, this is believed to be a potential cause for the complications experienced during the birth.

Apart from all the health risks that are involved, having a baby after 35 years of age could have some benefits. For example, the CDC says that women who wait to have children tend to have benefits like more resources at their disposal to care for the children, higher incomes, and these mothers are usually more educated.

If you are pregnant and over the age of 35, it is best to visit a doctor at the earliest, you find out you are pregnant. Remember that ultimately your age is not the only single factor responsible for the health of your pregnant. A study found that women who are older are more likely to feat that their pregnancies and births will be more complicated because of their advanced age.18 In some cases, this fear can very well cause adverse outcomes with the pregnancies.

It is entirely possible to have a healthy pregnancy even if you are over the age of 35. It is best to talk to y our doctor about how you can have a safe pregnancy and how to reduce any possible complications and risks for you and your baby. Here are some steps you should take to ensure that you have a healthy pregnancy:

• Eat a healthy and well-balanced diet.
• Take your prenatal vitamin and ensure it includes folic acid. If possible, start taking it before conception itself.
• Exercise regularly
• Avoid taking any harmful substances like drugs, smoking, and alcohol.
• Try to achieve a healthy weight before becoming pregnant.

You should also talk to your doctor about undertaking any types of screening tests that can ensure that your baby is healthy and also rule out any congenital disorders.

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