Prior studies have linked caffeine to increased risk of miscarriage, fetal death, and low birth weight, though results have been inconsistent.
In this study, researchers explored the link between caffeine intake from coffee and tea and the impact on fetal growth among 7,346 pregnant women from the Netherlands. Women filled out questionnaires during their pregnancy about the amount of coffee and tea they drank. Fetal growth was monitored by ultrasound during each trimester of pregnancy. In this study, each unit of caffeine reflects caffeine exposure equal to 1 cup of caffeinated coffee (90 mg caffeine). Results showed:
Say the authors, “Caffeine intake might selectively affect bone and skeletal development. Further follow-up studies are needed that focus on the effects of fetal caffeine exposure on postnatal skeletal and bone measurements.”
The American College of Obstetricians and Gynecologists states that moderate caffeine intake—200 mg a day or the equivalent of two 8-ounce cups of brewed coffee—does not appear to lead to miscarriage or premature birth. The College comments that it is not clear whether caffeine increases the risk of having a low-birth-weight baby. The organization advises that limiting caffeine is good for several reasons during pregnancy including the fact that it may interfere with sleep, increase nausea, lead to more frequent urination and as a result, increase the risk for dehydration. The bottom line? Check with your doctor about the amount of caffeine that is appropriate for you.
Do you know how much caffeine you are drinking each day? Caffeine amounts aren’t normally listed on product labels, so it is important to educate yourself about typical amounts found in beverages and food. Although this study looked at caffeine from coffee and tea, many other beverages and foods and even supplements or medications that may contain caffeine.
Also, it is important to know that all coffee and tea is not created equally: the amount of caffeine may vary from beverage to beverage depending on the type of coffee beans or tea leaves used, whether it is caffeinated or decaffeinated, and whether extra caffeine has been added through the addition of other ingredients such as chocolate or kahlua, for instance.
The International Food Information Council Foundation estimates the caffeine content of common beverages as follows:
(Am J Clin Nutr 2010;91:1691–8)