Caffeine is a component of many popular drinks like tea, coffee and cola, and is widely consumed by pregnant women, but is it safe? Moderate use of caffeine during pregnancy (not exceeding 300 mg per day) is generally considered safe, but large amounts of caffeine may cause harm.

During pregnancy, the half-life of caffeine increases significantly as a result of a reduction in activity of the liver enzyme, which is responsible for caffeine metabolism. This metabolic activity decreases by one third in the first trimester and by half in the second trimester. 

Caffeine leads to an increase in the concentration of catecholamines (adrenaline, dopamine and serotonin), affects the placental blood flow and impedes the transplacental transport of nutrients to the fetus. In addition, caffeine and its metabolites easily penetrate the placental barrier to the fetus, whose liver is not mature enough for normal caffeine excretion. As a result, any amount of caffeine can lead to changes in your baby’s sleep patterns or normal movement patterns in the later stages of pregnancy.

One cup of instant coffee (200 ml) generally contains 40-100 mg of caffeine and for comparison, one cup of tea generally contains 25-50 mg. The World Health Organization recommends to restrict caffeine intake to less than 300 mg per day during pregnancy. Teas lower in caffeine, like white, herbal or decaffeinated teas, are a safer alternative to coffee. Keep in mind that the method of preparation also impacts the caffeine content. Teas that are brewed for longer and in hotter water tend to produce higher levels of caffeine. Hot chocolate is another alternative that contains a much lower caffeine content per serving (around 5 mg per 250 ml cup).