Chronic medical disorders during pregnancy. Guidelines for prescribing drugs.

This report summarizes experience with representative drugs used to treat patients with medical disorders existing before pregnancy. Preconception counseling is ideal for determining whether drug therapy needs to be continued or altered. Focusing on the underlying disorder or morbid co-conditions, not the drug alone, may explain any additional hazards to the fetus. Avoiding multiple medications and selecting that which is presumably safest are encouraged. The best means of monitoring the safety and efficacy of therapy should be determined. Few drugs and their metabolites are linked to either specific birth defects or life-threatening problems, but their effects on the developing fetal circulation and central nervous systems are difficult to predict. Despite attempts to minimize fetal exposure, an increase in either the daily dose or duration of drug therapy may be necessary for optimal results. Although no drug is absolutely safe, the healthiest mother is most likely to deliver the healthiest infant.