If anyone needs a little caffeine, it’s a new mom. My labor with Cee took me through two mostly sleepless nights, and when she finally arrived, we took a little time to nurse and get to know one another, and then our whole little family took a long nap. When we woke up, the first thing I did was send my husband to get me a latte. The second thing I did was breastfeed my new baby again. That dose of caffeine felt like good therapy to me, but what about for Cee? Was it good for her?
A few weeks ago, I wrote about the safety of caffeine in pregnancy, and several readers wanted to know about the postnatal effects of caffeine – how mom’s caffeine intake might affect her breastfed baby. I promised to take a look at the literature and report back, and so here we are.
When you drink a cup of coffee, how much caffeine ends up in your breast milk?
Several studies have examined this question, and although they are small, they give us a general idea of the transfer of caffeine from mom’s blood to her milk. After a cup of coffee, caffeine is rapidly absorbed into mom’s blood and then passively diffuses across the epithelial layers of the mammary gland. Caffeine appears in milk within 15 minutes of consumption and peaks within an hour. The concentration of caffeine in breast milk ends up being about 80-90% of that in mom’s plasma. However, taking into account the amount of breast milk consumed and adjusting for body weight, studies have estimated that the infant receives no more than 10% of the maternal dose of caffeine, and likely much less (see here, here, and here).
Is this amount of caffeine safe for a baby?
Just because levels of caffeine in breast milk are low relative to what adults normally consume doesn’t mean that these amounts are necessarily safe to a baby. Another important factor is how efficiently a baby can metabolize caffeine, and it turns out that newborn caffeine metabolism is really slow. Whereas the half-life of caffeine in adults is around 2-6 hours, it is an average of 3-4 days in newborns and can be even slower in premature babies. In other words, a morning cup of coffee for mom will easily clear her blood by bedtime, but caffeine may linger in her breastfed newborn for much longer. Metabolism gradually ramps up as the baby matures and the necessary enzyme levels come on board, and most babies can metabolize caffeine at rates similar to adults by 5-6 months of age. Continue reading