I am a student parent and find that coffee helps me study. I drank coffee while pregnant and kept it well under the daily allowed amount. I am unsure what I can have while breastfeeding though. How much caffeine comes through breastmilk and is it unsafe for infants?
In most cases, drinking less than 300mg of caffeine a day will not affect your baby. Even if your child is extra sensitive to caffeine, the effects aren't serious, and they will go away if you eliminate caffeine from your diet.
Newborns tend to be more sensitive to caffeine than older babies. They can't break it down very quickly, so it can build up in their system. For children over 6 months (as well as for adults), the half-life of caffeine is about 4-7 hours. However, for a newborn, the half-life is anywhere between 65-130 hours. Thankfully for those of us with caffeine habits, babies quickly develop the ability to process caffeine (by 3 months, the half-life is reduced to 14 hours).
If you notice your baby become irritable, or agitated, or if he is having sleeping problems, you can cut caffeine out of your diet for a few days to see if that solves the problem. If you do have to stop drinking coffee, you should be able to re-introduce it after a couple of months.
Here are a couple studies done on caffeine and breastfeeding (I found them both through the National Library of Medicine).
This study says that for smaller doses of caffeine (from about 30 to 300mg), the infant will ingest between .06% and 1.5% of the maternal dose.
This study had 11 breastfeeding mothers drink 500mg of caffeine a day for 5 days. They monitored the heart rate and sleep patterns of the infants, and found no measurable effect from that dose of caffeine.
I have two contrary thoughts.
1/ Provided your caffeine intake is moderate, I am sure it isn't a problem. We have been drinking coffee and tea for generations. If you haven't started your homework coffee yet, then pay attention when you start. If there are noticeable changes that don't abate in a day or so, stop the coffee.
2/ If you aren't sure, if it a concern despite generations of evidence to the contrary, or if your baby demonstrates an unusual reaction, don't drink coffee. Your homework coffee isn't heart or blood pressure medication. It is essentially a luxury; figure something else out. Have an apple instead.
I see no reason not to give it a try. You won't do any permanent or serious harm. I expect no impact, but there is a small chance of a disruption of sleep patterns. This will make life miserable for a few days, but lots of things do that when you have an infant in your life.
I would avoid the "energy drinks" that are popular today. They worry me.