Evaluating the safety of medications during pregnancy and lactation

This article describes the types and limitations of studies conducted to evaluate the safety of medications during pregnancy and lactation. Conducting randomized clinical trials (RCTs) comparing drugs and placebo in patients who are pregnant or breast-feeding is considered unethical, because of the potential risk exposure to the fetus or neonate. Drug data on pregnancy outcomes and lactation effects can be derived from animal studies, but these studies cannot guarantee safety in lieu of clinical research in people. Human studies include case reports and epidemiology studies. In the absence of RCTs, epidemiology studies are the best way to identify associations between drug exposure and adverse pregnancy outcomes. Potential limitations of epidemiology studies include sample size, length of follow up, appropriate selection of comparison control groups, and recall bias. Determining the effects of drug exposure during breastfeeding depend on understanding the extent of drug transfer into breast milk, the effects of drugs on milk production and composition, and the extent and consequent effects on breast-fed infants of exposure to drugs in breast milk.