Caffeine… friend or foe? Americans love caffeine, and it’s found in countless food and beverage items: coffee, chocolate, soda, tea and even some medications. News headlines tell conflicting stories of its effects: one day, caffeine is safe and may even aid weight loss; the next, caffeine consumption is linked to everything from cancer to cardiovascular disease. Many scientific studies on caffeine safety are equally as contradictory, making it a challenge for consumers to know exactly what amount is safe.
The table below lists the amount of caffeine found in common foods and beverages:
Pregnant women and women trying to become pregnant are often told to avoid “too much” caffeine, as it has been linked to adverse effects like spontaneous abortions and restricted fetal growth. Here, we’ll break down the most recent (credible) research on caffeine safety for women trying to conceive and women who are pregnant or breastfeeding.
There is a growing body of evidence to support the importance of a healthy lifestyle among women trying to conceive. Strong evidence suggests, for example, that smoking cigarettes and drinking excessive amounts of alcohol and caffeine adversely affect fertility for both men and women. Conventional wisdom dictates that avoiding alcohol and cigarettes during pregnancy is the safest choice for the fetus; does the same warning hold for caffeine? A study published in March of 2016 by the National Institute of Child Health and Human Development found that women and their partners who limited caffeine consumption to two drinks per day were less likely to miscarry than those who exceeded that threshold. In 2015, the government of Australia published guidelines advising women trying to conceive to limit their daily intake to 200 mg, approximately the amount of caffeine found in two 8 oz. cups of coffee. While conclusive evidence directly linking high caffeine consumption with infertility is lacking, the association with increased risk warrants the suggested daily caffeine limit of two drinks (about 200 mg) per day for couples trying to conceive.
Pregnancy & Lactation
Why is there concern about caffeine consumption among pregnant women? The most simple explanation is that caffeine is a stimulant that can cross the placental barrier and enter the fetal bloodstream, and fetuses cannot fully metabolize it. The compound also has a longer half-life in pregnant women (15.08 hours) than in non-pregnant women (4.71 hours). Physicians have long warned pregnant and breastfeeding women to limit their consumption of caffeine because of possible adverse effects to the baby, such as preterm birth, restricted growth or miscarriage. Again, evidence of cause-and-effect seems to be lacking. In a 2015 position paper on the topic, the American College of Obstetricians and Gynecologists stated that, “moderate caffeine consumption (less than 200 mg per day) does not appear to be a major contributing factor” in either miscarriage or premature birth. The same recommendation to limit caffeine intake to approximately 200 mg per day, or about 2 cups of coffee, holds for pregnant women as well as those trying to become pregnant.
Breastfeeding women may also want to be cautious about the amount of caffeine they drink. Caffeine can pass into breast milk and, because of its stimulant effect, can interrupt an infant’s sleep pattern. Although the amount of caffeine that is passed through the breast milk to the baby is only about 1% of what the mother consumes, it can take babies up to 160 hours to fully process the compound. Organizations like the March of Dimes recommend that breastfeeding women limit their consumption to about 2 caffeine-containing drinks per day, or less if their babies are fussy or have difficulty sleeping.
So, while evidence that high caffeine intake causes infertility, preterm birth or miscarriage is lacking, the recommendations for pregnant and breastfeeding women (and those trying to become pregnant) is clear and nearly universal: consuming up to 200 mg of caffeine per day is perfectly safe and unlikely to cause any harm to either mother or baby.
American College of Obstetricians and Gynecologists http://www.acog.org/Resources-And-Publications/Committee-Opinions/Committee-on-Obstetric-Practice/Moderate-Caffeine-Consumption-During-Pregnancy
American Pregnancy Association http://americanpregnancy.org/pregnancy-health/caffeine-during-pregnancy/
Australian Breastfeeding Association https://www.breastfeeding.asn.au/bfinfo/breastfeeding-and-maternal-caffeine-consumption
The Fertility Society of Australia http://yourfertility.org.au/wp-content/uploads/2016/02/2015-11-19-Effects-of-caffeine-alcohol-and-smoking-on-reproductive-outcomes.pdf