During pregnancy, changes in your body mean caffeine stays in your body longer. It readily crosses the placenta and enters your baby’s circulation. Many women want to know, does it matter?
What Caffeine Does and Does Not Do
We know that unborn babies respond to caffeine by increasing heart rate.1 Heart rate changes were found with the equivalent of a cup of espresso or 30 grams of dark chocolate. When the caffeine use stops, the heartbeat returns to normal. Caffeine is also associated with an increase of uterine contractions. Despite these changes, research has failed to find any links between caffeine and miscarriage or poor fetal growth, birth defects and the normal development of children.2,3 One recent study found an association between the amount in 2 to 4 cups of coffee per day and small for gestational age, but this study was observational which means it is only able to show a relationship and definitely not a cause effect.4
What is the difference between a relationship and a cause and effect? It is possible the coffee (and the caffeine in the coffee) is responsible for the increased rates of small for gestational age. However, it is also possible that women who drink large amounts of caffeinated beverages have other things in common. For example, women who drink several soft drinks each day may be less likely to eat lots of vegetables. Overall research is not conclusive on any ill effects in pregnancy specifically from caffeine.
Research also suggests there are no behavioral or emotional changes in children whose mothers used caffeine during pregnancy. One study in Amsterdam followed a group of women and their children from pregnancy. They found no difference in risk for behavioral or emotional problems for children whose mothers used caffeine, even among women consuming the highest amounts of caffeine during pregnancy.5
How much is OK?
Until research is able to sort everything out, it is probably a good idea to limit your caffeine intake to less than 200 mg per day. But it occurs naturally in coffee, tea, chocolate and cocoa. It is also added to soft-drinks, over the counter drugs, stay-awake medications and allergy medications. This can make it a hard substance to avoid during pregnancy.
A 5 ounce serving of coffee can have up to 100 mg of caffeine, while a 5 ounce serving of tea averages around 50 mg. You can reduce your intake during pregnancy by reducing the amount of coffee and tea you drink, or by using caffeine-free varieties or herbal teas.
Soft drinks average about 36 mg of caffeine in a 12 ounce serving. Like coffee and tea, caffeine-free versions are available. Milk chocolate and cocoa have about 5 mg per serving, semisweet chocolate (the kind in chocolate chip cookies) averages 20 mg per 1 once.