Medications Often Pose Unknown Risks to Pregnant Women

When the morning-sickness drug thalidomide was introduced in the 1960s, little was known about how medication could affect a developing fetus. But when more than 10,000 babies were born with missing or shrunken limbs, medical experts quickly realized that drugs ingested by women during pregnancy can have powerful and potentially devastating consequences for their unborn children.

Nearly half a century later, doctors still struggle with the issue as the list of defective drugs continues to grow. Just this year:

  • The Food and Drug Administration (FDA) warned women taking topiramate, an anti-seizure drug sold under the brand name Topamax, that they face a higher risk of giving birth to babies with cleft palates.
  • The FDA warned that terbutaline, an asthma drug also used to stop preterm labor, may potentially cause maternal heart problems or death.
  • The Centers for Disease Control and Prevention warned that taking opioids for pain relief just before or early in pregnancy – including Vicodin, OxyContin or Tylenol with codeine – increased fetal risk of congenital heart defects.

In addition, the FDA has recently warned that antidepressants such as Paxil, Lexapro, Prozac and Celexa can cause birth defects when taken by pregnant women. And physicians have long known that the acne drug Accutane can cause severe birth defects.

Despite these problems, studies indicate that 64 percent of pregnant women take at least one prescription drug during pregnancy. On average, pregnant women take three to five medications, according to

Pregnancy Creates an Ethical Paradox

Determining a drug’s impact on a developing fetus is anybody’s guess. In fact, conclusive data on drug safety during pregnancy doesn’t exist for most prescription medications. Why? Because exposing pregnant women and unborn babies to the risk of a clinical trial testing for drug safety has been considered unethical.

However, women with chronic conditions like asthma, epilepsy or high blood pressure cannot go nine months without treatment without posing serious health risks to both mother and baby. So doctors must carefully weigh a necessary medication’s benefits against the often uncertain risk that it might affect fetal development.

To manage the uncertainty, the FDA in 1979 created a system to rate drug safety during pregnancy based on existing data. The drug categories – A, B, C, D and X – group medications from the very safe – category A – to those posing great risk – category X. However, more than 60 percent of drugs fall into category C, a gray area that provides vague and easily misinterpreted information.

The FDA is now drafting new guidelines to help drug makers include pregnant women in clinical trials. In the meantime, drug companies and advocacy groups have launched more than 40 online registries to monitor drug effects on pregnant women and their babies.