In utero drug exposure and the media.(DRUGS, PREGNANCY, AND LACTATION)

Over the past several decades, media coverage of medical journal studies has played a powerful role in perpetuating the bias against the use of certain medications during pregnancy.

As physicians, we read medical journals and other professional materials, but we also pay attention to the media. We may not necessarily have an opportunity to check the veracity and quality of a study we read or hear about, so the message we get may influence some of our perceptions and even our practices.

The impact on the public is enormous. At Motherisk, we are often contacted by pregnant women who are afraid of taking a medication because they heard about a study indicating a drug was not safe during pregnancy. It's not unusual for such reports to lead a woman to seek termination of an otherwise wanted pregnancy.

The thalidomide disaster heightened the public's awareness and sensitivity to the concept that every drug is potentially a human teratogen. But the reality is that, almost 50 years later, very few drugs have been shown to be human teratogens. Still, physicians and women are hesitant about the use of medications during pregnancy, even when the drug is highly needed.

The notable examples in the medical literature date back to a study published in the early 1970s that reported an association between prenatal exposure to the hormones in oral contraceptives and congenital malformations (Lancet 1973; 1:941-2). At that time, the study caused huge anxiety, resulting in oral contraceptives being labeled as pregnancy category X. But in the 1990s, a large number of studies and two meta-analyses, including one we conducted at Motherisk, failed to show any increased risk of malformations associated with prenatal exposure to OCs, which, by far, are the most common prescription product inadvertently taken by women during pregnancy.

The anxiety created by the initial paper continued until a few years ago, when OCs were switched to category D. It is not possible to estimate how many women may have terminated their pregnancies because of such exposures, but this is clearly an example of how one study in a major journal led to an unwarranted degree of anxiety.

Another important example is the story of spermicidal contraceptives. It made biologic sense that spermicide may not destroy all sperm and that a damaged sperm that fertilizes an egg could possibly cause congenital malformations. In the early 1980s, a study using an HMO database reported finding an association between spermicide prescriptions and malformations (JAMA 1981; 245:1329-32). The number of children with malformations thought to have been exposed to spermicide, although significant, was small. The study used data from the HMO records of women who were prescribed a spermicide. But this information did not prove the women actually took it into pregnancy; some women may have stopped using it before they got pregnant, or may have never taken it at all.