Breast milk samples from nursing mothers who were taking a type of antidepressant or corticosteroids were lower in protein compared to samples from nursing mothers who were not taking these medications, according to a study funded in part by the National Institutes of Health (NIH). Moreover, milk samples from mothers taking other kinds of anti-inflammatory medications were lower in fat compared to samples from mothers not taking these medications.
The authors concluded that the lower nutrient levels in milk from mothers taking the medications could potentially affect infant health, particularly those born preterm. However, the study could not determine if the differences in nutrient levels resulted from the medications or were linked to the health conditions requiring the medications. They stressed that the findings were preliminary and called for further research.
The study was conducted by Essi Whaites Heinonen, M.D., Ph.D., of the Karolinska Institute in Stockholm, Sweden, and Kerri Bertrand, M.P.H., and Christina Chambers, Ph.D., M.P.H., of the University of California, San Diego. NIH funding was provided by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) and the National Center for Advancing Translational Sciences.
Background
Breastfeeding has health benefits for infants and is recommended as the sole source of nutrition for children in the first six months of life. Among human milk components, carbohydrates are linked to infant weight gain, proteins are linked to infant length, and fats aid development of the infant nervous system.
More than 70% of breastfeeding mothers take some form of medication. However, little is known about how prescription medications taken during breastfeeding could potentially influence the nutritional content of human milk.
Results
The study included samples from 63 participants taking selective serotonin reuptake inhibitors (SSRIs) to treat depression and other mood disorders, 33 participants taking corticosteroids to control inflammatory conditions like rheumatoid arthritis and inflammatory bowel disease, 20 taking disease-modifying antirheumatic agents and other kinds of anti-inflammatory drugs, 28 participants with untreated mood disorders, 67 participants with untreated inflammatory disorders, and 64 participants with no mood or inflammatory disorders who were not taking any of these medications.
Although the average nutrient levels of all the samples were within the normal range, the study did find significant differences between the groups. Samples from participants taking SSRIs had an average of 0.85 grams per milliliter (mL) of protein and samples from those taking corticosteroids had an average of 0.88 grams per mL—both less than the average of 1.08 grams per mL from women not taking these medications.
Fat content of breast milk samples from participants taking other kinds of anti-inflammatory drugs (3.40 grams per 100 mL) was lower than the control group (3.85 grams per 100 mL), as well as another control group of 113 participants not taking any medication for an inflammatory condition (4.38 grams per mL).
Similarly, the total energy (a combined estimate of calories provided by fat, protein, and carbohydrates) was lower for breast milk samples from participants taking other kinds of anti-inflammatory drugs (69.56 kilocalories per 100 mL) compared to the control group (77.16 kilocalories per 100 mL) or participants with inflammatory conditions who were not taking anti-inflammatory medications (80.60 kilocalories per 100 mL).
Significance
“The bottom line is that breastfeeding mothers who are taking these medications for their own health do not need to be alarmed,” Dr. Chambers said. “The findings are very preliminary, and it’s far too early to know if they are meaningful at all for the baby.”
The authors said it is unclear from their results whether the lower nutrient levels they found in milk samples from participants taking medications could present risks for healthy infants, who presumably would compensate for lower nutrient levels by consuming more milk. However, it is possible the lower nutrient levels associated with taking these medications while breastfeeding might pose risks for exclusively breastfed preterm and ill infants. Until more is known, they urged clinicians, as per routine clinical care, to monitor the growth and health of breastfeeding infants whose mothers are taking these medications.
Next Steps
The authors called for further research to determine whether the lower nutrient levels they observed in the milk samples of study participants taking SSRIs and anti-inflammatory medications are related to the medications they took or due to other factors associated with their underlying health conditions.
Reference
Heinonen EW, et al. Macronutrients in human milk exposed to antidepressant and anti-inflammatory medications. JAMA Network Open DOI: 10.1001/jamanetworkopen.2024.53332 (2025)
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