Drug Risks for Pregnant Women
What you need to know about medication when you’re expecting
Halfway through her third pregnancy, Liz Diament, a 33-year-old art curator from Silver Spring, MD, developed an itchy rash all over her body. When she visited a dermatologist and asked him to look at the rash, he whipped out a handheld device and tapped on some keys. "Oh, well," he said, "The drug I thought would help most is a C, so we'll have to talk about that."
Diament's doctor was referring to a five-letter rating system established almost 30 years ago by the Food and Drug Administration (FDA) to help doctors determine whether a drug poses a risk to a fetus. Category C means that no studies have been done, or that animal studies have shown a risk to the fetus but because there haven't been follow-up studies in humans, "risk cannot be ruled out."
Diament decided to forgo the drug, and luckily, the rash eventually went away. Many women, however, have no choice but to take medications during their pregnancy to treat chronic conditions (such as asthma or epilepsy), pregnancy-related bacterial infections, or severe allergies, says Sheila Weiss Smith, Ph.D., an associate professor at the University of Maryland's School of Pharmacy.
The average woman will take three prescription drugs during pregnancy, according to Smith. Most of what is known about the safety of these medications in pregnant women is based on animal studies, which aren't necessarily predictive of what will happen in humans, says Gideon Koren, M.D., director of Motherisk, a research and consulting service based at the Hospital for Sick Children in Toronto, that tracks the effects of drugs during pregnancy and breastfeeding. More often than not, the safety of a drug during pregnancy is based on both a degree of guesswork and a hope that it won't harm the fetus.
The Trouble With Testing
Over the last decade, many obstetricians and researchers have grown frustrated with the lack of data available on drugs that are often used in pregnancy. At a meeting in Washington, D.C., convened by the FDA and the National Institutes of Health (NIH) on the proper dosing of drugs during pregnancy, some researchers complained that drug companies call doctors to find out about available data on the safety of a drug on a fetus, but don't conduct enough of their own studies.
"We want to get the data but are leery of doing studies," says Bert Spilker, M.D., Ph.D., former senior vice president of scientific and regulatory affairs at Pharmaceutical Research and Manufacturers of America (PHRMA). "We don't want to put women at risk unnecessarily," explains Dr. Spilker. "What we think is reasonable is that we collect data on pregnant women taking a drug and put the information on the package label so that women can talk to their doctors and make an informed choice."
Doctors involved in both research and advocacy efforts say the significance of having up-to-date, easily accessible information on the safety of drugs during pregnancy cannot be overstated. At the FDA/NIH meeting, participants listened to a report of a young woman who stopped taking her asthma medication while pregnant and subsequently died of an asthma attack before the baby was born. "Without information, many women simply refuse to take the drugs, not realizing the harm they can cause themselves and their baby," says Marietta Anthony, vice president for women's health research at the Arizona Health Sciences Center."