Research

Medication Use during Pregnancy: Risk Factors for Birth Defects?

Like many families affected by birth defects, CDC wants to find out what causes them. Understanding risk factors, such as certain medications, that might increase the chance of having a baby with a birth defect will help us learn more about the causes.  Better information on the safety or risk of specific medications will allow women and their doctors to make informed decisions about treatment during pregnancy.  

To learn about birth defects, CDC coordinates and collaborates with many other researchers on one of the largest U.S. studies to understand the causes and risk factors for birth defects, the National Birth Defects Prevention Study. This study of major birth defects helps identify a number of specific medications associated with an increased risk of birth defects.

 

Gaps in Current Knowledge

A 2011 study of all medications approved by FDA from 1980 through 2010 found that 91% of the medications approved for use by adults in general had insufficient data to determine the risk of using the medication during pregnancy.¹ CDC and its collaborators are working to fill this gap and continue to study medication use during pregnancy in order to understand how specific medications might affect the 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 doctors make treatment decisions during pregnancy.

Some recent findings on possible associations 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 in the baby. In addition, it might decrease the risk of some birth defects in the baby when the woman uses it because she has a fever, because untreated fever can increase the risk of some birth defects. [Read summary]

 

Antidepressants: Depression is a serious illness. Women should not change medications or stop taking medications without first talking with their doctor about the available options.

• One recent study found that taking bupropion (used for depression and to stop smoking) during pregnancy might increase the risk of having a baby with certain heart defects. [Read summary]
• A number of studies have identified risks to the fetus and newborn associated with use of antidepressant medications. Several studies have shown an increased risk for heart defects associated with taking selective serotonin-reuptake inhibitors (SSRIs) during early pregnancy. SSRIs are a common group of antidepressant medications. Data from the National Birth Defects Prevention Study (NBDPS) showed that taking SSRIs during pregnancy might increase the risk of anencephaly, craniosynostosis, or omphalocele. [Read article]

 

Medications to treat diseases: Maternal diseases are serious conditions.  Women should not change medications or stop taking medications without first talking with their doctor about the available options.

• Pregnant women with asthma who use certain medications might have an increased risk of having a baby with a heart defect. One type of asthma medication, bronchodilators, showed an increased risk in one study. [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 doctor before pregnancy.
  
  
• 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, or hypospadias. [Read summary]
  
  
• One study found that pregnant women who have high blood pressure (hypertension) or took certain hypertension medication appeared to have an increased risk of having a baby with left or right obstructive heart defects or septal heart defects. Hypertension is a serious disorder, particularly in pregnancy.  Women should talk to their doctor about the best medication options to treat their condition during pregnancy.[Read article]
  
  
• Some recent case reports suggested that pregnant women taking mycophenolate mofetil (MMF; CellCept), which is used to help prevent transplant organ rejection or to treat lupus nephritis, might have an increased risk of having a baby with birth defects. However, these are serious disorders and pregnant women should not stop or start taking any type of medication that they need without first talking with a doctor.  [Read summary]
  

 

Medications to help with 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] It is difficult to determine whether these findings are due to the use of the clomiphene citrate or because these women had difficulty getting pregnant due to some underlying conditions that affected fertility.
  
  
• Taking progestins (used to help with infertility and 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 in the baby. However, sulfonamide, which is often in used in combination with trimethroprin (which is thought to increase the risk for birth defects) or nitrofurantoin use was associated with several birth defects. [Read article]

 

 

References

1. Adam MP, Polifka JE, & Friedman JM. Evolving Knowledge of the Teratogenicity of Medications in Human Pregnancy. Am J Med Genet Part C. 2011;157:175-82.