Growing toxicological and epidemiological interests in new therapeutic compounds have arisen with the recent increase in frequency of pregnancies in women with renal disease. Angiotensin-converting enzyme inhibitor and angiotensin II receptor antagonist, at least in the late stages of pregnancy, is associated with adverse fetal development and can cause pulmonary hypoplasia and neonatal anuria. In utero exposure to immunosuppressive drugs poses challenges to management of pregnant renal transplant recipients. Mycophenolate mofetil, a new antiproliferative drug to inhibit inosine monophosphate dehydrogenase, has been recently reported to cause major fetal malformations. Whilst such alleged adverse fetal events are potential concerns for obstetricians and physicians, an understanding of different types of risk estimates and strengths of evidence is also needed - we further elaborate and provide perspective on how to interpret the available information in clinical decision-making of drug use in pregnancy.