Caffeine in pregnancy?

Most people have some amount of caffeine in their diet, whether it is from coffee, tea, soft drinks, or energy drinks. Given the prevalence of these products, many women of reproductive age consume these beverages, but seldom stop to wonder - how much is safe during pregnancy?

Caffeine and it’s metabolites cross the placenta and can be found in the amniotic fluid and fetal blood.  Metabolism is also slowed during pregnancy, thus the effects are exerted for a prolonged duration. Despite this, systematic reviews evaluating the effects of caffeine on pregnancy have demonstrated insufficient evidence that caffeine should be completely avoided.

Most recommendations state that women can safely consume up to 200 mg of caffeine per day, without negative effects on fertility or pregnancy.  Data on the effects of caffeine on fertility is limited, but adverse effects do not seem to occur with low intake (i.e. less than 200 mg/day).  During pregnancy, higher intake can increase risk of miscarriage and very high intake levels (>1000 mg/day) have shown a potential for increased risk of birth defects.  Interestingly, caffeine has shown a protective effect against the development of gestational diabetes mellitus and pre-eclampsia (high blood pressure during pregnancy). 

During lactation, high levels of caffeine may cause irritability and sleep disturbances, thus intake should still be limited (200-300 mg per day).

You’re probably wondering how much 200 mg of caffeine is - see the table below for the caffeine content in a number of common substances:

Reference:  March of Dimes

Other common substances not listed above:

• Espresso – 40 mg (range 30-90 mg)
• Iced Tea (e.g. Snapple, Arizona, Nestea) – between 10-42 mg  
• Coffee Ice Cream – 50-84 mg

For a very detailed list of caffeinated products, check out: http://www.cspinet.org/new/cafchart.htm

In summary, it appears that moderate caffeine intake before, during and following pregnancy is safe for most women.  You should try to consume <200 mg/day and make sure to consider “hidden sources” that may not be obvious. 

As always, these are general guidelines and you should consult your doctor to ensure this information applies to you.  Stay tuned for another post on the effects of caffeine on exercise.