Hi there and thank you for your question!
Caffeine passes from you to your child in small amounts through breast milk but most likely will not harm your child if you are drinking a low to moderate amount (about 300mg or less per day which is about 2 to 3 cups of coffee)(1). There has been some reports of irritability, poor sleep and jitteriness in infants of mothers who drink a high amount (about 10 cups of coffee ore more per day) (1). If you notice your child becoming fussy or irritable after you drink coffee, you may consider reducing the amount you drink.
Be mindful that there are other dietary sources of caffeine other than coffee such as:
Check out some of our Lifestyle pages related to breastfeeding for more tips on taking care of yourself and your child. Hope this helps!
Anna Ng, RD
1. "Maternal Diet." Centers for Disease Control and Prevention. Reviewed October 8, 2020. Accessed December 18, 2020. https://www.cdc.gov/breastfeeding/breastfeeding-special-circumstances/diet-and-micronutrients/maternal-diet.html#:~:text=Caffeine%3A,to%203%20cups%20of%20coffee).