Globally, a significant proportion of pregnancies are complicated by serious medical illness requiring treatment [1]. Despite an assumption—or perhaps a wish—that pregnancy occurs only against a backdrop of “perfect health,” women often confront illness in the face of pregnancy or pregnancy in the face of illness. A multitude of examples come to mind: a pregnant woman contracts malaria, a woman with diabetes becomes pregnant, a woman with a persistent psychiatric illness that is well-controlled by medication wants to have a child, or perhaps a pregnant woman is diagnosed with HIV at her first antenatal care visit. In each of these cases, the necessity of medication use during pregnancy to treat or manage chronic disease or new infection is unquestionable.
In fact, a significant proportion of pregnant women take medication at some point during their pregnancy, if not throughout the course of their pregnancy. In the United States, as many as 70% of women took at least one prescription medication during pregnancy [2]. Certain disease states make this need vivid. For example, in the global context of HIV/AIDS, medication use during pregnancy is essential: approximately 1.5 million women living with HIV give birth across the world each year [3] and use antiretroviral medicines to manage their illness and prevent mother-to-child transmission of the infection.
To understand the significance of the burden of disease and subsequent use of medications during pregnancy, however, we must acknowledge that medications behave differently in the pregnant body [4]. Just as treating children as merely miniature adults in the context of medical science is irresponsible, so, too, is treating pregnant women as merely women with big bellies [1]. The pregnant body can act as a “wild card” when it comes to metabolizing medications—during pregnancy, certain medications dosed for non-pregnant adults can clear the body too quickly to offer therapeutic benefit [4]. Others may specifically target the developing fetus, causing harm, and fail to treat the pregnant woman’s illness at all.
But we lack robust evidence to assess the ways in which medications are metabolized by the pregnant body, the extent to which medications treat the woman’s health condition, and the degree to which medications affect the fetus. Indeed, pregnant women have been called the “last true therapeutic orphan” [5]. Against this backdrop, the reasons to pursue research with pregnant women are not just medical, they are ethical.