Caffeine and pregnancy
Information about caffeine and pregnancy
What is caffeine and where is it found?
Caffeine is a mildly addictive stimulant which is found naturally occurring in foods and drinks such as coffee, tea and cocoa. Caffeine is also used as an additive in soft drinks, energy drinks, some chewing gums and medications. It is therefore possible that pregnant and lactating women may consume caffeine from multiple sources.
Why is it important to limit caffeine intake during pregnancy?
Caffeine can be absorbed freely across the placenta, but cannot be broken down by either the placenta or the foetus. Therefore, the amount of caffeine the foetus is exposed to is very close to the amount consumed by the mother.
High caffeine intakes during pregnancy (greater than 400 mg per day) have been shown to increase the risk of miscarriage and sudden infant death syndrome. Additionally, a recent study examining caffeine consumption in 2,500 pregnant women, showed negative effects on foetal growth from as little as 200 mg per day. This negative effect on birth weight increased as caffeine intake increased, and was seen even in women who were non-smokers. Smoking during pregnancy is well known to adversely affect foetal growth.
Besides the issue with caffeine and foetal growth, many caffeine-containing foods, such as tea, contain significant amounts of tannins which make it difficult to absorb iron. Iron is an essential nutrient, but the human body can only absorb a limited amount of the iron from food. The need for iron rises during pregnancy, and many pregnant women find it difficult to consume and absorb enough dietary iron. Insufficient iron during pregnancy can adversely affect foetal growth. Therefore, factors which reduce the absorption of dietary iron (such as tannins in tea and coffee) should be avoided.
How much caffeine is safe during pregnancy?
Although not all studies have reported a link between caffeine and negative effects on the foetus, there is sufficient evidence to suggest that caffeine may be harmful. Considering this, the guideline for the upper limit of caffeine intake in pregnancy has been reduced from 300 mg per day to 200 mg per day throughout pregnancy.
Many women naturally develop an aversion to caffeinated drinks during pregnancy; however, those who do not, as well as those women who are planning a pregnancy, should be advised to reduce their caffeine intake if necessary to below 200 mg per day. Care should be taken not to replace these drinks with sugary or alcoholic drinks. In other words, caffeine containing foods and beverages should be minimized but not replaced with unhealthy alternatives.
How much caffeine is safe during breastfeeding?
Caffeine does not enter freely into breastmilk, and concentrations in breastmilk are lower than those found in the mother’s blood. However, caffeine is eliminated much more slowly from pre-term and newborn infants than from adults, and some caffeine can be transferred to breastmilk, causing irritability and poor sleeping pattern in infants. Despite this, moderate intakes of caffeine are compatible with breastfeeding, with an intake of 2-3 cups of caffeinated beverages (corresponding to 200-300 mg of caffeine) per day considered to have no adverse effect.
How do I know how much caffeine I am consuming?
The table below outlines the caffeine content of beverages and foods that are the common sources of caffeine in the Irish diet. From this table, the daily limit of 200 mg of caffeine can still include as much as one cup of brewed coffee and two cups of tea per day.
Food or Drink Portion Size Caffeine Content (mg) Coffee, brewed 1 cup 111 mg (range 102-200 mg) Coffee, instant 1 cup 78 mg (range 27-173 mg) Coffee, decaffeinated 1 cup 4 mg (range 3-12 mg) Espresso 1 shot 40 mg (range 30-90 mg) Tea, brewed 1 cup 44 mg (range 40-120 mg) Snapple (fruit and diet versions) 1 bottle (480 ml) 42 mg Pepsi 1 bottle (500 ml) 32 mg Pepsi Max 1 bottle (500 ml) 30 mg Diet Coke 1 bottle (500 ml) 64 mg Coke 1 bottle (500 ml) 48 mg Caffeine-free Coke 1 bottle (500 ml) 0 mg 7-up (diet and regular) 1 bottle (500 ml) 0 mg Red Bull 1 can (250 ml) 80 mg Hot cocoa 1 cup 8 mg Milk chocolate 1 bar 11 mg Dark chocolate 1 bar 31 mg Coffee-flavoured ice cream 1 scoop 16 mg (range 15-17 mg)
Information adapted from the Centre for Science in the Public Interest
The exact amount of caffeine will vary according to cup size, brewing methods and brand of tea or coffee. 1 cup = 200 ml; 1 shot = 30 ml; 1 bar = 45 g; 1 scoop = 60 g