What you need to know about medication safety in pregnancy
Few drugs are major teratogens, but heightened vigilance is crucial to protect your pregnant patient
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Most drugs enter breast milk
The amount of drug that an infant consumes from breast milk depends on the medication’s chemical properties as well as the dosage, frequency, and duration of exposure.2 Contraindications and cautions are usually either theoretical or based on findings from case reports that often conflict or confuse. In theory, it is safer for the mother to take the medication just after infant feeding or just before the infant’s longest sleep period.
The TABLE also lists the effects of drugs in the breastfed human infant. Again, the information comes from the Reprotox database, access to which requires a subscription. For additional information, try the free LactMed site at https://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT.
Nearly all drugs are excreted in breast milk, usually in small amounts (often less than 5% of the weight-adjusted maternal daily dose). The amount of drug or metabolite in an infant’s serum also is determined by the volume of breast milk, age of the infant, and other exposures.
Avoid prescribing multiple medications, if possible, and choose “safe” drugs from among the options in categories that include a number of teratogenic medications, such as anticonvulsants.
Determine the best method to monitor therapy. For example, use a peak flow meter for asthma, a portable blood pressure monitor for hypertension, and so on.
Focus on keeping the patient healthy. The healthiest mother is most likely to deliver the healthiest infant.
Keep the underlying disorder in mind, as well as the drug, when choosing a drug.
Know which drugs are clearly linked to birth defects. These include phenytoin, warfarin, alcohol, methotrexate, diethylstilbestrol, cis-retinoic acid, valproic acid, and carbamazepine.
Pay special attention to the first trimester. Too little is known about the first-trimester effects of the vast majority of drugs for them to be considered safe.
Suspect a drug-related effect
A medication may be the cause in any newborn manifesting signs of anemia, hepatitis, hepatotoxicity, hepatorenal dysfunction, and hyperbilirubinemia. This includes breastfed infants. An adverse drug-related effect should also be suspected when an infant exhibits signs of jaundice, floppiness, jitteriness, poor suck, diarrhea, or growth restriction.
