Balancing Act: Safe and Evidence-based Prescribing for Women of Reproductive Age
Birth defects are the leading cause of infant mortality in developed countries. Birth defects are common; for example, the US CDC estimates that 3% of births in the USA result in major birth defects. The exact number of defects attributed to teratogenic medication use is not known. However, potentially teratogenic medications are commonly prescribed for women of reproductive age. A UK-based study using the national General Practice Research Database found that one out of every 164 women was prescribed a US FDA-designated category X medication in early pregnancy. In the USA, an analysis of the National Ambulatory Medical Care Survey (NAMCS) found that from 1998 to 2000, 11.7 million potentially teratogenic medications were prescribed to women of childbearing age in the USA. Furthermore, 6% of US pregnancies are exposed to potentially teratogenic medications, and up to half of US pregnancies are exposed to drugs for which there is limited evidence of safety during pregnancy in humans.
Pregnant women may have chronic medical conditions that persist during pregnancy or may develop new medical problems during pregnancy, so the use of prescription medication may be both appropriate and necessary. However, given the frequency of use of potentially teratogenic medications and the high stakes, it is essential that providers take a systematic approach to the use of these medications, using the best available evidence. Failure to engage women in appropriate discussion of the risks and benefits of medication use can result in inadvertent exposure to the fetus, and at times even pregnancy termination. Alternatively, a lack of guidance about medication use during pregnancy may result in unnecessary discontinuation of important medications, resulting in maternal or fetal harm.
Medication use in pregnancy presents clinicians and patients with complex challenges. First, scientific evidence proving teratogenicity is notoriously limited, so that regulatory bodies, clinicians and patients must base decisions on imperfect information. Second, medical training in toxicology and pregnancy risk, as well as preconception and contraceptive counseling, is limited, especially among primary care clinicians. Third, half of all pregnancies in the USA are unplanned – a rate that reflects the challenges women and men face in accessing contraceptive services. Fourth, upon this foundation of limited training, incomplete data and inadequate access to preventive services, within a short office visit, clinicians and patients must engage in decision-making that is medically complex and emotionally charged. As one FDA expert describes, “All prescribing and drug-use decisions in pregnancy require consideration of various clinical and individual factors including the potential effects of the drug on the mother and fetus, the severity of the mother’s condition, maternal tolerance of the drug, coexisting maternal conditions, the impact of maternal illness on the fetus, and available alternative therapies”.
For women of reproductive age who are considering taking teratogenic medications, the following services are essential:
• For women who are not pregnant, discussion of fertility goals, including the potential risks, benefits and alternatives of a medication if she becomes pregnant;