Study suggests prenatal exposure to medications increases autism risk

According to the Centers for Disease Control and Prevention, ASD is on a rise in the United States:

• In 2000, about 1 in 150 children were diagnosed with ASD.
• In 2014, about 1 in 59 children were diagnosed with ASD.
• In 2022, about 1 in 31 children were diagnosed with ASD.

Cholesterol is a critical substance in the body. There is no life without it. Sterol biosynthesis is the process of how the body makes cholesterol. The brain makes its own cholesterol and needs it to grow and develop. This process is especially important before birth and during early childhood. Some medications can slow down or block how the body makes cholesterol.

The researchers looked at 6.14 million health records of mothers and their children. They focused on 14 medications that affect how the body makes cholesterol. When these medications are prescribed to women during pregnancy, their children had a higher chance of developing ASD later in life. This risk may be even greater if more than one of these medications is prescribed at the same time.

The medications evaluated in the study are used to treat many different health conditions:

• Antidepressants (for depression)
• Antipsychotics (for severe mental health conditions)
• Anxiolytics (for treatment of anxiety)
• Beta-blockers (heart medications)
• Statins (cholesterol-lowering medications)

The generic names of these medications are:

• aripiprazole
• atorvastatin
• bupropion
• buspirone
• fluoxetine
• haloperidol
• metoprolol
• nebivolol
• pravastatin
• propranolol
• rosuvastatin
• sertraline
• simvastatin
• trazodone

Medications can have two labels — a brand name given by a pharmaceutical company that manufactures it and a generic name.

To see if you used one of the medications in the study, you can:

• Check your medication bottle or information sheet for the generic name, which is usually printed in smaller letters and often in parentheses.
• Search the FDA drug database using the medication name to see if the brand name or generic name matches one of those medications included in the study.

The study found that the prescriptions of these medications during pregnancy increased from 4.6% of pregnancies in 2014 to 16.8% of pregnancies in 2023.

Nine of the 14 medications are among the most commonly prescribed drugs in the U.S. In 2022, they were prescribed more than 400 million times a year.

The results of this study show:

• 3.7% of children developed ASD when mothers were not prescribed one of these medications.
• 5% of children developed ASD when mothers were prescribed one or more of these medications.

Risk can be different for each person and depends on factors like mother and child genes; lifestyle; health conditions the mother may have; the dose, duration, and timing of the exact medication; and many other factors. More research is needed to better understand this risk. We hope that further research can shed light on these important questions.

This is new information. Studies using large data were not available before. In addition, previous studies grouped medications by the health challenges they treat. In this study, the UNMC team grouped medications based on if they can inhibit how the body makes cholesterol.

We would like to highlight three critical take-home messages.

1. These findings come from a scientific study that used one of the largest health databases in the world. This study is part of more than 15 years of research aimed at understanding how cholesterol production affects the developing brain. This work was guided by science, not by politics or personal beliefs.
2. We are not suggesting anyone stop taking important or lifesaving medications during pregnancy. Decisions about medication should always be made through open conversations between patients and their health -care providers.
3. Mothers should not blame themselves if they used these medications during pregnancy and their child has ASD. Others should not blame them either.

Most women who used these medications had children without ASD, and some women who did not use them still had children with ASD. More research is needed to understand which children are at the highest risk of developing ASD when the mothers use these medications during pregnancy.

No. Do not stop any medication without talking to your health care provider. Your provider can help you understand the benefits to your health and any risks to your baby. Talk with your provider about whether there are safer medication options for you that can successfully treat your condition.

There are no official guidelines for genetic testing related to cholesterol-related genes and pregnancy. A genetic counselor may be helpful, but insurance might not cover testing. Some studies suggest people with certain genes may be more sensitive to the side effects of medications.

No testing is needed beyond the already recommended tests during pregnancy. No prenatal test can diagnose ASD. Ultrasounds can only check for visible physical problems.

This is a personal decision. You should consider both the benefits to your health and the possible risks to your developing baby. Talk with your health care provider about your concerns and options. You can also ask your pharmacist when you pick up your medication. Drug companies that make these medications share known risks. To learn more about possible side effects during pregnancy, you can talk with your provider or check trusted sources, such as the MotherToBaby website. MotherToBaby is a service of the Organization of Teratology Information Specialists and provides evidence-based information on medication safety during pregnancy and breastfeeding.

We do not know yet. Risk for developing ASD in a child depends on many factors. These include, dose, duration, timing during pregnancy, the genetics of you and your child, lifestyle, and many other factors.

ASD has many causes. This study shows a higher chance of ASD in children when these medications are prescribed in pregnancy. However, most women who used these medications did not have a child with ASD.

No. Regular well-child visits with your provider are enough unless concerns come up. Always contact your health care provider if you have concerns about your child’s development.

Follow the well-child visit schedule. Discuss your child’s developmental milestones with your health care provider.

Available research studies do not support this. More research is needed in this area.

In most cases only very small amounts of some medications can pass into breast milk. Other medications may not be as safe. Talk with your health care provider or visit trusted websites, like the MotherToBaby website, to learn more.

No, these medications are important and can often save lives. The brain needs the most cholesterol during early development and soon after birth. The adult brain does not need to make large amounts of new cholesterol because brain development is already complete. Many of these medications do not easily reach the adult brain because the brain has a natural barrier that protects it.

This study did not examine those conditions. It focused only on ASD. At this time, there is not enough research to know whether these medications affect the chances of developing these other conditions.

We do not know for sure. Some medications have not been tested to see if they affect cholesterol production. Talk with your health care provider if you have questions.

This study did not examine medication used by fathers. More research is needed to understand if this plays any role.

Yes, if you have one child with ASD, the chance of having another child with ASD is higher. This is mostly because of family genetics. Not using these medications may help lower one risk, but it does not take away all risk.