Prednisone is generally considered safe for breastfeeding at doses up to 20 mg per day. Only a small fraction of the drug passes into breast milk, and at typical doses, the amount an infant receives is too low to cause harm. At higher doses, simple timing strategies can reduce your baby’s exposure even further.
How Much Reaches Your Baby
Prednisone transfers into breast milk in small quantities. Studies consistently show that the relative infant dose, the standard measure of how much drug a breastfed baby actually receives compared to the mother’s weight-adjusted dose, falls well below the 10% threshold that pharmacologists use to flag concern. At doses of 20 mg per day or less, the amount your baby ingests through milk is considered negligible.
Your body also helps limit exposure naturally. Prednisone is converted into prednisolone in the liver, and both forms appear in breast milk, but neither accumulates there. Concentrations rise after you take a dose and then drop relatively quickly, which is why timing can be a useful tool if you’re on a higher dose.
The 20 mg Threshold
Clinical guidance from reproductive health specialists, including recommendations from Duke University’s Reproductive Rheumatology program, draws a clear line: at doses up to 20 mg daily, you can breastfeed without any special precautions. The infant exposure at this level is minimal and not associated with adverse effects.
If your dose exceeds 20 mg per day, the recommendation shifts slightly. Rather than stopping breastfeeding, you can reduce your baby’s exposure by waiting 4 to 6 hours after taking your dose before nursing. Drug levels in milk peak within the first couple of hours and decline steadily after that, so this waiting window catches the period of highest concentration. If you pump during that window, discard that milk and feed your baby with previously stored milk or formula instead.
Short Courses vs. Long-Term Use
A short burst of prednisone, the kind commonly prescribed for asthma flares, allergic reactions, or autoimmune episodes lasting 5 to 7 days, poses very little concern during breastfeeding. The exposure is brief, and infants metabolize the small amounts they receive without difficulty.
Longer courses at moderate to high doses warrant more attention, not because a single feeding becomes dangerous, but because cumulative exposure over weeks or months raises different questions. A retrospective study of infants born to mothers on prednisolone found that about 18% of those babies showed signs of reduced adrenal function, with mothers taking an average of around 14 mg daily. One infant in that study required hospitalization for an adrenal crisis at two months old. That study looked at prenatal exposure rather than exposure through breast milk specifically, but it illustrates why prolonged steroid use deserves monitoring regardless of the route.
Effects on Milk Supply
One concern that gets less attention is the potential for prednisone to reduce milk production. Corticosteroids may interfere with prolactin, the hormone that drives milk synthesis. Reports of this effect are limited, and many women take prednisone without noticing any supply changes, but the possibility is real enough that the NHS Specialist Pharmacy Service flags it as something to watch for.
If you notice your supply dropping while on prednisone, track your baby’s weight gain and wet diapers. These are the most reliable indicators of whether your baby is getting enough milk. Frequent nursing or pumping can help counteract a temporary dip in production, and supply typically recovers after you taper off the medication.
Practical Tips for Nursing on Prednisone
- At 20 mg or less per day: No special timing needed. Breastfeed on your normal schedule.
- Above 20 mg per day: Take your dose immediately after a feeding, then wait 4 to 6 hours before the next session. Pump and discard if needed during that window.
- Watch for supply changes: Monitor your baby’s weight gain if you’re on prednisone for more than a few days, since corticosteroids can occasionally reduce milk volume.
- Short courses are lowest risk: A standard 5 to 7 day taper is unlikely to affect your baby or your supply in any meaningful way.
What to Watch for in Your Baby
At standard doses, side effects in breastfed infants are rare. The signs that would prompt concern are the same ones you’d notice with any feeding issue: unusual sleepiness, poor feeding, irritability, or slow weight gain. These are not commonly reported with maternal prednisone use, but they’re worth knowing about, especially if you’re on a higher dose or a longer course. Infants exposed to corticosteroids over extended periods could theoretically develop suppressed adrenal function, though this is far more of a concern with direct administration to the baby than with the trace amounts transferred through milk.