Background: Drug safety has the highest priority in the treatment of pregnant women, as any effect on fetal development will not be immediately evident, and the harm that ensues may have lifelong adverse consequences.
Methods: This review is based on pertinent publications retrieved by a selective literature search and on expert assessment on the basis of the current evidence.
Results: The teratogenic and fetotoxic drugs that are most important in their magnitude of effect and/or frequency of exposure are discussed, along with their characteristic effects. For each of the main indications for drug treatment during pregnancy, the current drugs of choice are stated, regardless of their approval status for use by pregnant women. Drugs are designated as "tolerable" in pregnan- cy if there is currently no reliable evidence of a human teratogenic effect but the state of the evidence is still inadequate for a conclusive determination. Such drugs can be given, in consideration of the risks and benefits, in case the drugs of choice are out of the question. Unplanned pregnancies arising in women who are taking "tolerable" drugs do not necessitate the immediate switch or discontinuation of the drug. On the other hand, drugs with known teratogenic or fetotoxic effects are desig- nated as "contraindicated." For any pregnant woman exposed to such a drug, the risk must be assessed individually, and a risk management strategy must be determined.
Conclusion: For most indications for drug treatment in pregnant women, drugs are available with adequate clinical experience supporting drug safety. In all fields of medicine, drug safety information for pregnant women needs to be stated more precisely and in a manner more suitable for clinical application; moreover, the explanation to the patient must enable her to assess the risk realistically, but should not arouse undue anxiety. Drug safety in pregnancy demands the continuous collec- tion of observational data, so that risks can be assessed as precisely as possible and false suspicions can be laid to rest, both for new drugs and for those that have already been in longstanding use. To this end, the Pharmacovigilance Institute (Pharmakovigilanz- und Beratungszentrum, PVZ) for Embryotoxicology critically assesses the current state of the evidence and carries out its own relevant observational studies.