How much caffeine can you have while breastfeeding?

Up to about 300 mg a day counts as low to moderate, the CDC says, roughly two to three cups of coffee. Caffeine passes into breast milk in small amounts, and at that level it usually doesn’t affect the baby.

After nine months of counting to 200 mg, a lot of new parents aren’t sure whether the rules still apply. They loosen a little. The line goes up to about 300 mg, and it’s there for the baby, who gets a small share through the milk.

We’d keep it to two or three cups, all before lunch. The baby is one reason. The other is you. A new parent’s nights are already broken, and caffeine late in the day takes some of the sleep you do get.

When the baby is more sensitive

The CDC notes that preterm and younger newborn babies break caffeine down more slowly, so mothers of these babies might want even less. Very high intakes, around 10 or more cups of coffee a day, have been linked to babies who are irritable, fussy, jittery or sleep poorly. If your baby seems fussier after a day when you had a lot of caffeine, the CDC suggests cutting back.

What 300 mg looks like

Why the morning

Three 8 oz coffees at 7am, 9am and 11am leave about 47 mg in you at an 11pm bedtime. The same three at 9am, 1pm and 4pm leave about 81 mg, over the higher of our two bedtime lines (80 mg). Across 24 studies, caffeine cut total sleep by about 45 minutes on average, and new parents don’t have 45 minutes to spare.

Your clearance is back to normal

Late in pregnancy, caffeine leaves the body much more slowly. In a 1982 study of women near term, clearance was only 39% of the usual adult value, and when they were retested weeks after the birth it had risen more than threefold. Within weeks of the birth, your own body is back to clearing caffeine at about the usual speed.

Add up your day

The how much is too much tool has a breastfeeding setting that adds your drinks against the 300 mg line, and the cutoff clock shows what they leave at your bedtime. For more on caffeine and breastfeeding, the CDC points to LactMed, the NIH’s database on medicines and breastfeeding.