Some principles to avoid adverse effects to the unborn child from medications taken during pregnancy:

• use caution when it comes to any woman who is pregnant, who might be pregnant, or who might soon become pregnant;
• know the patently toxic drugs in order to avoid these drugs, or else to provide for effective contraception;
• be aware that there is great uncertainty and lack of knowledge when it comes to most drugs;
• avoid any treatments whose efficacy is uncertain;
• take both the mother and the child into account when evaluating a treatment’s harm-benefit balance;
• take maximum precautions during the first trimester of pregnancy: it is best to use a tried and tested drug, at minimal doses, and for the shortest time possible;
• late in the pregnancy, be aware of the drug’s known effects outside of pregnancy, and take them into account;
• keep in mind that the long-term effects on the development of the unborn child are unknown;
• inform patients about the dangers of medications taken during pregnancy;  
• organise monitoring and management of any adverse effects that can be anticipated in children.

©Prescrire 1 August 2013

Source: "Femmes enceintes et médicaments" Rev Prescrire 2013 ; 33 (358).