Caffeine intake during pregnancy has been linked with numerous adverse health outcomes and therefore intake should be limited during this time.
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 women who are breastfeeding may consume caffeine from multiple sources.
Effects on the Foetus
Caffeine can be absorbed freely across the placenta but cannot be broken down by either the placenta or the foetus. Therefore maternal caffeine consumption is closely linked with placental and foetal caffeine concentrations, and the foetus can be easily exposed to the effects of caffeine.
The principal enzyme involved in processing caffeine in humans is absent in the placenta and foetus. The infants’ liver can actually only begin to metabolise caffeine during the first three months of life therefore caffeine can exert a toxic effect on the baby in the womb.
In the 90’s guidelines for caffeine consumption in pregnancy were based on studies which have reported the heavy caffeine intakes (<400mg/day) can increase the risk of miscarriage (Fenster et al, 1991) and sudden infant death syndrome. Additionally, a caffeine intake of >300mg/day has been linked to unhealthy low birth weights. However, recent research suggests that caffeine intake during pregnancy should be even limited more strictly.
In a recent study which examined caffeine consumption amongst 2,500 pregnant women, it was observed that the adverse effects on foetal growth increased progressively as daily caffeine intakes increased from 200 – 300 mg/day.
Besides the effect of caffeine on foetal growth, many caffeine containing foods such as tea contain significant amounts of tannins, which may negatively impact iron absorption. Iron is essential nutrient but it has limited availability, i.e. the human body only absorbs a limited amount of iron in the food. The mum’s requirements for iron rises during pregnancy and many pregnant women find it difficult to consume and absorb sufficient dietary iron. Lack of sufficient iron during pregnancy can adversely affect foetal growth, therefore another reason to go easy on teas and coffees.
Although not all studies have reported a link between caffeine and negative foetal outcomes, there is sufficient evidence to suggest that caffeine may be harmful, and therefore it is best not to consume excessive amounts. Interestingly many women naturally develop an aversion to caffeinated drinks during pregnancy
Taking the most recent scientific research into consideration, pregnant woman or those planning a pregnancy should aim to reduce their caffeine intake to 200mg/day or below.
From table below, the daily limit of 200mg of caffeine can still include one cup of brewed coffee and two cups of tea per day. Note the difference between the decaffeinated and regular drinks! Obviously the caffeine content is dependent upon the length of brewing time for teas and coffees.
|Food or Drink||mg Caffeine|
|Cup brewed coffee||111|
|Cup instant coffee||78|
|Cup decaff coffee||4|
|Can red bull||80|
|Bottle diet coke||39|
|Bottle coke, pepsi, pepsi max||29|
|Bottle 7up free, coke zero||0|
|Bar dark chocolate||31|
|Bar milk chocolate||11|