Caffeine in Coffee: What’s the Straight Scoop?

I’m writing this post with my coffee cup in hand. I enjoy my coffee. I cringe when I hear healthcare providers tell breastfeeding mothers they should give up coffee because caffeine in coffee is so bad for the breastfed baby. I’d say that mandate, along with advice about chocolate, ranks as a little extreme.

Although I pride myself on knowing the formal research to back up my point, I don’t often cite the exact studies in my posts here. (This is a blog, not an academic paper!) Today, though, I feel compelled to do so. (The studies are old, and small, but in this day and age, who is going to fund more studies?)

What’s the straight scoop?  How much caffeine gets to the baby? What adverse effects might occur? How long does it take to excrete the caffeine? When are peak concentrations are highest? 

Caffeine in coffee: How much are we talking?

It’s not possible to have this discussion without knowing the amount of caffeine being consumed, and whether such consumption occurs all at once or in increments. For example:

• One 6-oz cup of coffee contains about 80-135 mg of caffeine, depending on the type of beans used and the strength of the brew.
• Starbucks’ 20-oz Venti caffé latte is made with 2 shots (about 4 oz) of espresso, which has more caffeine per ounce than regular coffee. (Some customers ask for three shots.)
• Caffeine has a long half-life. That means that it takes many hours to metabolize (process) and excrete it. Hence, consuming more caffeine before the first “dose” has been metabolized can intensify the possible adverse effects.

Amount of caffeine in coffee doesn’t tell the whole story

The amount of a substance ingested by the mother is not identical to the amount in her milk or her infant’s blood.

In a descriptive survey, Ryu¹ determined the concentration of caffeine in newborn serum in relation to the amount of caffeine the lactating mother had ingested. (Newborns were 11-22 days old on the first day of the study.)

• Nine lactating mothers consumed 750 mg of caffeine daily (divided doses) for the first 5 days, and then for the next 4 days, they ingested no caffeine at all. 
• On day 5, the concentration of caffeine in the maternal milksamples averaged 4.3 micrograms/ml.
• No caffeine was detected in milk samples on day 9.

The mean concentration of caffeine in the newborn’s blood on day 5 was 1.4 micrograms/ml. In all except two newborns, the amount of caffeine in the blood on day 9 was undetectable.

Effects of caffeine ingestion

What are the effects of caffeine ingestion? Building on his other work, Ruy² conducted another descriptive survey to determine the effects of maternal caffeine ingestion.

• Eleven lactating mothers ingested 1 cup of decaffeinated coffee for 5 days and 1 cup of coffee containing 100 mg of caffeine for 5 days.
• The 24-hour heart rates of their infants during the caffeine period were not significantly different than heart rates during the non-caffeine period.

It would be unethical to give excessive amounts of caffeine to breastfeeding women in order to study the effects on their infants.

However, clinical observations of breastfeeding infants who are exposed to excessive amounts of caffeine in coffee or from another source, either in one “dose” or from a cumulative effect of several caffeinated beverages, describe infants who are wakeful, hyperactive, wide-eyed, active, unable to sleep very long.³ Hence, moderation is key.

Time when peak concentrations of caffeine occur

Stavchansky⁴ et al. conducted a descriptive study to determine when peak concentrations of caffeine occurred in the maternal milk.

• Mothers who had been breastfeeding for 3½ to 17 weeks were given a single dose of 100 mg of caffeine, and then collected their milk from zero to 24 hours later.
• Milk analysis showed that peak concentrations of caffeine in the milk (1.98 and 4.3 micrograms/ml) ranged from 3/4 of an hour to 2 hours.

This timeline suggests that adverse effects, if they do occur, will be greatest within 2 hours of the time that the mother ingests the caffeine.

Is any amount of caffeine dangerous for infants?

Nearly all drugs are potentially harmful.

However, for as long as I’ve been a nurse, caffeine has often been given to NICU infants to reduce periods of apnea (cessation of breathing for at least 20 seconds.) Its widespread use is increasing, too.

If it were flat-out “dangerous”, I doubt it would be given to some of the most vulnerable infants. I’m just trying to give some perspective here. That said, I’d also warn that those infants are consuming a therapeutic dose, not an overdose, and they are monitored continually.

What are the take-home points?

• Limit caffeine intake to the equivalent of 1 to 2 cups of regular coffee per day during lactation. That’s a maximum of about 200 mg of caffeine for the entire day. This recommendation is based on the Institute of Medicine’s Nutrition During Pregnancy and Lactation.⁵ (Yes, it’s “old” but it is still arguably the most authoritative source for this recommendation.) Here’s the mention of caffeine.

• Watch the size of the “cup.” Remember, a “cup” of coffee is a traditional 6-oz china cup. The mug in front of me (and maybe your mug, too!) holds 10 ounces, and my favorite travel mug holds 15 ounces! A contemporary 12-oz mug is likely to contain around 200 mg of caffeine.

• Watch the timing. It’s best to consume a caffeinated beverage immediately after the infant suckles. That’s because research shows that caffeine has a very long half-life, and the peak effects occur up to 2 hours after ingesting the caffeine.⁴ Most infants will wait more than 2 hours before suckling again.

• Beware of multiple sources of caffeine. Caffeine in coffee is just one possible source of caffeine consumption. Other beverages contain varying amounts of caffeine: a 6-oz cup of hot black tea contains about 50 mg of caffeine and a 12-ounce can of a cola beverage contains about 50 mg or possibly more. Hence, the person who drinks multiple cans of cola all day long is consuming much more caffeine than the person who enjoys their morning cup of coffee. I think I’ve made a clear case that the chocolate isn’t all that big of a deal, but again, look at the total consumption and the cumulative effect. Calculate the total intake of caffeine in coffee and other sources of caffeine for the day.

• Reduce overall daily load of caffeine. Avoiding cola drinks (which often have a ton of sugar, too!) is a good idea. Alternatively, 7UP, ginger ale, and root beer contain little or no caffeine.

• Caffeine does not change human milk composition.⁶ It actually may stimulate milk production.

• Complete abstinence is unnecessary. Moderation is the key.

Bottom line

In summary, one “usual” size cup of coffee, or two small cups of coffee, are unlikely to create a problem for the breastfed infant. Other sources of caffeine, if consumed in many “doses,” can be.  Overall awareness and moderation are the key to initiating and continuing breastfeeding without negative effects.   

Do you drink coffee while lactating? What have you been told about caffeine in coffee and breastfeeding? Share your experiences in the thoughts below!

  1.   Ryu JE. Caffeine in human milk and in serum of breast-fed infants. Dev Pharmacol Ther. 1985;8:329-37.

  2.   Ryu JE. Effect of maternal caffeine consumption on heart rate and sleep time of breast-fed infants. Dev Pharmacol Ther. 1985;8:355-63.

  3.   Rivera Calimlim L. The significance of drugs in breast milk. Pharmacokinetic considerations. Clin Perinatol.  1987;14:51-70.

  4.   Stavchansky S, Combs A, Sagraves R, Delgado M, Joshi A. Pharmacokinetics of caffeine in breast milk and plasma after single oral administration of caffeine to lactating mothers. Biopharm Drug Dispos. 1988;9:285-99.

  5.   Institute of Medicine; Nutrition During Lactation. Washington DC: National Academy Press; 1991.

  6.   Nehlig A, Debry G. Consequences on the newborn of chronic maternal consumption of coffee during gestation and lactation: a review. J Am Coll Nutr. 1994;13:6-21.