Any treatment used in pregnant women must take into account the effects of the substance in question of the fetus and the particular sensitivity of the latter during the first three months of development. The majority of drugs used in cardiology can be prescribed during pregnancy: digitalis preparations, furosemide, certain beta-blockers, verapamil, nifedipine (except during the first three months), quinidine, disopyramide, lignocaine, flecainide, amiodarone, heparins (non-fragmented and low molecular weight), central antihypertensive agents, dipyridamole and aspirin. In contrast, some drugs should be avoided because of insufficient information regarding their maternal and fetal consequences (bumetamide, modamide, the most recent beta-blockers, cibenzoline, ticlopidine) or because of harmful adverse effects on the fetus (spironolactones, bipyridines, diltiazem) or the newborn infant (angiotensin converting enzyme inhibitors). Finally, with certain medications (propafenone, oral anticoagulants), it is important to be able to compare maternal risks due to the disease and fetal risks induced by the drug. Modification of the conditions of use of these drugs and very careful monitoring of the patient most often suffice to avoid untoward events or complications with potentially serious medicolegal consequences and which may implicate the liability of the prescriber.