The short answer is yes, you can have some caffeine if you’re breastfeeding. However, we all know that the long answer is more complicated than that. Really, it depends on how the caffeine affects your baby. Your baby will tell you when you’ve had too much caffeine by becoming overstimulated, and will be wide-eyed, active, alert and perhaps fussy.
The Womanly Art of Breastfeeding states that the amount of caffeine in five or fewer five-ounce cups of coffee (less than 750 ml) will not cause a problem for most mothers and babies. (It might be helpful to measure the number of ounces in your typical coffee mug, as many are 8 to 12 ounces or more.) And don’t forget that when figuring caffeine intake, remember all sources of caffeine such as colas, some pain relievers, some cold medicines, and other medicines. Chocolate contains theobromine which can act like caffeine in both the mother’s and baby’s systems.
In Breastfeeding: A Guide For the Medical Profession (fifth edition), by Ruth A. Lawrence, M.D. and Robert M. Lawrence, M.D., the authors write:
“Caffeine ingestion has been singled out for discussion because it is a frequent concern, but the data provided in most reviews are misleading. With a given dose of caffeine that is comparable to that in a cup of coffee, the level in the milk is low, (1% of level in mother) and the level in the infant’s plasma is also low. However, caffeine does accumulate in the infant.”
In addition, the authors note that “Smoking has been observed to augment the caffeine effect.” This resource also cites other studies which indicate that a baby’s ability to metabolize caffeine develops by three to four months of age.
If you suspect your baby is reacting to caffeine, you may try avoiding caffeine from all sources (coffee, tea, soft drinks, medications, chocolate) for two to three weeks. You should keep in mind, however, that abruptly discontinuing all caffeine may result in headaches or other symptoms of withdrawal. If caffeine stimulation is the cause of your baby’s sleeplessness, s/he should begin settling down to more normal sleeping patterns between a few days and two weeks after you eliminates caffeine from your diet.