Infant Drug Exposure: Risks, Safe Medications, and What Parents Need to Know

When a mother takes medication during pregnancy or while breastfeeding, her baby may be exposed to those drugs — this is called infant drug exposure, the transfer of pharmaceutical compounds from mother to infant through the placenta or breast milk. Also known as fetal or neonatal drug exposure, it’s not always dangerous, but it requires careful understanding because babies’ bodies process drugs very differently than adults. Their liver and kidneys aren’t fully developed, so even small amounts of certain medications can build up and cause harm.

Breastfeeding and drugs, how medications pass into breast milk and affect nursing infants is another major concern. Many moms assume if a drug is safe during pregnancy, it’s safe while nursing — but that’s not always true. Some drugs concentrate in breast milk, while others barely pass through. For example, acetaminophen is generally safe in both cases, but ibuprofen and certain antidepressants need careful timing and dosing. Then there’s neonatal drug effects, the range of symptoms infants may show after exposure to medications before or after birth — from drowsiness and poor feeding to breathing problems or withdrawal signs like tremors and crying.

Infant drug exposure doesn’t just come from prescription pills. Over-the-counter pain relievers, herbal supplements, nicotine, alcohol, and even some cold medicines can cross over. A 2023 study showed that nearly 9 out of 10 breastfeeding mothers took at least one medication, and half didn’t know if it was safe for their baby. That’s why knowing which drugs are risky matters. For instance, certain antibiotics like tetracycline can stain baby teeth, and some anti-seizure meds can cause liver stress in newborns. On the flip side, many common meds like low-dose aspirin or specific thyroid pills are fine with proper monitoring.

What you need to watch for isn’t just the drug name — it’s timing, dosage, and how often it’s taken. A single dose of a painkiller after delivery? Usually low risk. Daily use of an anxiety medication while breastfeeding? That’s a different story. The key is consistency and communication. Always tell your doctor you’re pregnant or nursing before starting any new drug, even if it’s sold without a prescription. And if your baby seems unusually sleepy, fussy, or isn’t feeding well after you started a new medication, don’t wait — call your pediatrician.

There’s no need to avoid all meds during pregnancy or while breastfeeding. Many conditions — like high blood pressure, depression, or diabetes — need treatment, and stopping medication can be more dangerous than the drug itself. The goal isn’t to be perfect, it’s to be informed. That’s why the posts below cover real-world cases: what happens when moms take NSAIDs late in pregnancy, how warfarin affects nursing infants, why some generic switches matter more for babies, and what to do when a medication causes unexpected reactions in newborns.