As a coffee lover, I was happy to learn the suggested limit is 2-3 cups of coffee (300 mg caffeine) spread throughout the day when body feeding. I remember how happy I was to return to my normal coffee intake postpartum, only to have some moms claim it was why my baby had so much energy and didn't care for naps. In reality it was just his energetic personality (he's now 4 and still the same). Oh the mom shaming/guilt 🙄.
Studies have found caffeine in moderation has no effect on sleeping patterns or heart rate. However, please keep in mind that everyone's body is different. You know your baby better than others so if you notice significant changes try drinking less coffee and see what happens.
Around 1.5% of the caffeine you drink will pass to your baby via human milk. However, newborn babies metabolize caffeine much slower so that amount can accumulate overtime. Thus the caffeine can stay in their system for days. When babies are around 5-6 months they can metabolize caffeine at a faster rate so effects are less.
Coffee and breastfeeding Referenced:
• American Academy of Pediatrics recommendations: https://www.healthychildren.org/English/ages-stages/baby/breastfeeding/Pages/Alcohol-Breast-Milk.aspx
• Maternal caffeine consumption and infant nighttime waking: https://pubmed.ncbi.nlm.nih.gov/22473365/
• Effect of maternal caffeine consumption on heart rate and sleep time of breast-fed infants: https://pubmed.ncbi.nlm.nih.gov/4075934/
• Disposition of dietary caffeine in milk, saliva, and plasma of lactating women: https://pediatrics.aappublications.org/content/73/1/59.long