Research

CDC and collaborators study medication use during pregnancy to understand how specific medications might affect an unborn baby. Results of these studies give women and their healthcare providers better information on the safety or risk of using specific medications during pregnancy. This information supports their ability to make informed decisions about treatment options.

Learning the Effects of Medication during Pregnancy

The U.S. Food and Drug Administration (FDA) regulates medications to ensure their general safety and effectiveness for the U.S. population. Drug companies have to test all prescription medications to see if they are safe and effective before they can be made available to the public. Pregnant women usually are not included in these tests. This is because of the possible risks to the unborn baby. As a result, we have little information about the safety of most medications during pregnancy when they first become available. But, listed below are a few ways we work to find out more about the effects a medication might have when taken during pregnancy.

Centers for Birth Defects Research and Prevention Studies

CDC funds the Centers for Birth Defects Research and Prevention, which collaborate on large studies such as the National Birth Defects Prevention Study (births 1997-2011) and the Birth Defects Study To Evaluate Pregnancy exposureS (to start in 2014). These studies work to identify risk factors for birth defects and to answer questions about medications taken during pregnancy.

Adverse Event Reports

Drug companies are required to report problems with medicines to the FDA. Healthcare providers, researchers, and the public, including pregnant women, also can report suspected problems directly to the FDA MedWatch Program, via the website: http://www.fda.gov/Safety/MedWatch/default.htm.

Pregnancy Registries

Drug companies sometimes conduct special studies using pregnancy registries. Registries enroll pregnant women who have taken a certain medicine. Then, after these women give birth, the health of their babies is compared with the health of the babies of women who did not take the medicine. Pregnancy registries are a useful way to study the effects of a particular medication because they allow researchers to gather health information both during a pregnancy and after delivery. This allows us to get a clearer picture of how other health issues and life events may impact pregnancy outcomes. For a list of current pregnancy registries and how to enroll, women may visit the FDA Pregnancy Registry website: http://www.fda.gov/ScienceResearch/SpecialTopics/WomensHealthResearch/ucm251314.htm.

Current Knowledge about Using Medication during Pregnancy

The information we have is limited. A 2011 study of medications approved by the Food and Drug Administration (FDA) from 1980 through 2010 found that 91% of the medications approved for use in adults lacked sufficient data to determine the risk of birth defects due to use of medications during pregnancy. [Read summary]

In addition, specific types of birth defects are rare. To determine whether or not an association between a particular medication and a specific birth defect exists, researchers need to review data from many pregnancies. This information can be hard to collect.

The good news is that CDC and other researchers are working to gather more information on medications used during pregnancy. We are working hard to understand how specific medications might affect an unborn baby. Although the studies mentioned below are just one step toward determining the risk of different medications during pregnancy, they contribute to the information available to help women and their healthcare providers make treatment decisions during pregnancy.

Notable Research Findings

Some recent findings on possible links between certain medications and birth defects are described below.

Over-the-counter medications:

• Taking acetaminophen (used for pain relief) during the first trimester of pregnancy did not appear to increase the risk of major birth defects. Also, taking acetaminophen might decrease the risk of some birth defects in the baby when a pregnant woman uses it to treat a fever. This is because untreated fever can increase the risk of some birth defects. [Read summary]

Antidepressants: Abruptly stopping the use of antidepressants can have serious consequences. Women should not change medications or stop taking medications without first talking with their doctor about the available options.

• A number of studies have identified some risks to the fetus and newborn associated with use of antidepressant medications. Selective serotonin-reuptake inhibitors (SSRIs) are a frequently prescribed group of antidepressant medications. Several studies have shown an increased risk for heart defects associated with taking SSRIs during early pregnancy. A 2007 study using data from the National Birth Defects Prevention Study (NBDPS) showed that taking SSRIs during pregnancy may increase the risk of anencephaly, craniosynostosis, or omphalocele. [Read article]
• A 2010 study found that taking bupropion [Wellbutrin®](used to treat depression/anxiety and to quit smoking) during pregnancy might increase the risk of having a baby with certain heart defects. [Read summary]
• A 2013 study looked at venlafaxine use during the first trimester of pregnancy and the risk for birth defects. Researchers found that venlafaxine use during early pregnancy was not common, but that it was more common among mothers of babies born with certain birth defects , including anencephaly, some heart defects, cleft palate, and gastroschisis. This is the first study to show these links, so more research is needed to understand and confirm them. [Read summary]
• CDC’s Morbidity and Mortality Weekly Report published a new study in 2016 looking at how often women aged 15-44 years filled a prescription for an antidepressant medication. CDC researchers found that about 15% of women aged 15-44 years (or about 1 in 7) with private health insurance filled a prescription for an antidepressant. [Read summary]

Medications to treat chronic health conditions: Chronic health conditions are serious and without treatment may be life-threatening. Women should not change medications or stop taking medications without first talking with their healthcare provider about the available treatment options.

• Asthma: Pregnant women with asthma who use certain medications might have an increased risk of having a baby with a heart defect. A particular type of asthma medication, bronchodilators, might increase the risk for heart defects. [Read summary] Another type of medication used to treat asthma, corticosteroids, might increase the risk of having a baby born with cleft lip and/or cleft palate. [Read summary] However, it is important that asthma be well controlled in pregnancy. Women should discuss the best treatment options with their healthcare provider before and during pregnancy.
• Thyroid conditions: Recent studies suggest that pregnant women who have a thyroid disorder might have an increased risk of having a baby with craniosynostosis [Read summary], hydrocephaly (build-up of fluid on the brain), or hypospadias. [Read summary]
• High blood pressure: One study found that pregnant women who have high blood pressure (hypertension) or took certain hypertension medications appeared to have an increased risk of having a baby with certain heart defects (left or right obstructive defects or septal defects). Hypertension is a serious condition, particularly in pregnancy. Women should talk to their healthcare provider about the best medication options to manage their condition during pregnancy.[Read article]
• Autoimmune and immunodeficiency diseases: Some recent case reports suggest that pregnant women taking mycophenolate mofetil (MMF; CellCept), which is used to help prevent transplant organ rejection or to treat lupus nephritis, have an increased risk of having a baby with birth defects. However, transplants and lupus are serious conditions, and pregnant women should not stop or start taking any type of medication that they need without first talking with a healthcare provider. [Read summary]
• Epilepsy (Seizure disorders): Epilepsy, and sometimes other conditions such as migraine headaches and mood and anxiety disorders, can be treated with antiepileptic, also called anticonvulsant, medications. Examples of these medications include valproic acid and carbamazepine. Previous studies have found that babies born to women who take certain antiepileptic medications during pregnancy have an increased risk for birth defects. Women prescribed antiepileptic medications may need to continue treatment during pregnancy. Not following a prescribed treatment plan may have worse outcomes than exposure to a particular medication. Therefore, when possible, women should discuss the best treatment options with their healthcare provider before pregnancy or as soon into the pregnancy as possible. In some cases, it may be possible to switch to a different medication that has fewer risks for causing problems during pregnancy. [Read summary]
  • One study looked at topiramate, a medication used to treat seizures. It is also considered for treatment of sleep and eating disorders, migraines, other mental health disorders, and weight loss. Researchers found that use of topiramate during the first trimester of pregnancy was associated with an increased risk of cleft lip with or without cleft palate in infants. When making treatment decisions just before or during pregnancy, it is important that women and their healthcare providers weigh the benefits of using medications, such as topiramate, to control symptoms, along with their potential risks for birth defects. [Read summary]

Medications to treat infertility:

• Taking clomiphene citrate (commonly used to help women who have difficulty getting pregnant) just before or during early pregnancy might increase the risk of having a baby with certain birth defects. [Read summary] However, it is difficult to determine whether these findings are due to the use of the clomiphene citrate or because of some underlying health condition causing both the women’s fertility and the birth defect.
• Taking progestins (used to treat infertility and an ingredient found in birth control pills) during early pregnancy might increase the risk of having a baby with hypospadias. [Read article]

Medications to treat infections:

• In one study, taking penicillins, erythromycins, or cephalosporins (antibiotics used to treat infections), did not appear to increase the risk of birth defects. However, use of sulfonamide (often used in combination with trimethroprin, which is thought to increase the risk for birth defects) or nitrofurantoin was associated with several birth defects. [Read article]

Medications to treat pain:

• Healthcare providers often prescribe painkillers called opioids for pain management. Unfortunately, we do not have enough information about the effects of prescription painkillers on a pregnant woman and her unborn baby. However, one study found that some birth defects, including spina bifida and certain heart defects, were linked with use of opioids during early pregnancy. [Read summary] Researchers looking at opioids in a different study also found an increased risk for spina bifida when these medications were used during pregnancy. [Read summary] When making treatment choices, women and their doctors should think about the benefits and risks of using opioids to manage pain.