Caffeine and Pregnancy

Safety of caffeine consumption during pregnancy is controversial. Some studies say as little as two cups of coffee a day creates a risk factor. 

Caffeine is a stimulant.  It increases your blood pressure and heart rate, both of which are not recommended during pregnancy. Caffeine also increases the frequency of urination. This causes reduction in your body fluid levels and can lead to dehydration.

Caffeine crosses the placenta to your baby.  Your baby's metabolism is still maturing and cannot fully metabolize the caffeine. Any amount of caffeine can also cause changes in your baby's sleep pattern or normal movement pattern in the later stages of pregnancy. Remember, caffeine is a stimulant and can keep both you and your baby awake.

Caffeine is not only found in coffee but also in tea, sodas, chocolate, and even some over-the-counter medications that relieve headaches.

The following information, adapted from the websites listed at the bottom of the page, will help you understand more about caffeine and your pregnancy.

The March of Dimes notes that during pregnancy, caffeine easily passes from the mother to her unborn child through the placenta. A developing fetus may have higher and more sustained blood levels of caffeine than the mother because of the immature metabolism of the fetus. A few studies have shown that even moderate caffeine consumption affects fetal heart rate and movement patterns.

Some studies have found that pregnant women who consumed large quantities of caffeine (five or more cups of coffee a day) were twice as likely to miscarry as those who consumed less, while fewer or no effects were seen at lower levels of caffeine consumption. 

High caffeine intake during pregnancy should be avoided. Individual sensitivity to caffeine may vary for both pregnant women and developing fetuses, and risks of moderate caffeine consumption are not clear. Women trying to become pregnant may conceive sooner if they limit caffeine intake to moderate amounts. To minimize infants' exposures to caffeine, breastfeeding women can avoid very high caffeine intake.

Caffeine's Effects on Fertility
Some studies have found a link between high levels of caffeine consumption by women and delayed conception. Those who consumed more than 300 mg of caffeine per day were twice as likely to have conception delayed for a year or more. Another study also linked high caffeine intake to delayed conception, but only in women consuming 500 mg or more (about four cups of coffee) per day.

Caffeine and Breast Feeding
Caffeine can enter the breast milk of nursing mothers.  According to the American Academy of Pediatrics, "Caffeine tends to build up in babies systems because their bodies cannot get rid of it very easily. A morning cup of coffee is not likely to harm your baby, but too much caffeine in a breast feed baby can cause problems such as poor sleeping, nervousness, irritability, and poor feeding.

Caffeine in Coffee, Tea, Chocolate and Other Products
The caffeine content of a serving of coffee or tea depends on the beans or leaves used, serving size, and the method of preparation.  An 8-oz. cup of  brewed coffee averages 150 milligrams (mg) of caffeine. Instant coffee contains less. Black tea averages 80 mg per 8-oz. cup. Green tea contains less. A 12-oz. caffeinated soft drink may contain 30-60 mg. (See the table below for more specific values.)

Other sources of caffeine include chocolate, chocolate syrup, hot cocoa, and certain medications. Amounts differ greatly from one such source to another. Chocolate or cocoa generally has very low caffeine content. Medications containing caffeine include some formulations for pain relief, migraine, the common cold, diuretic purposes, and delaying sleep. Unlike foods and beverages, FDA-approved medications carry labels that say how much caffeine they contain. Some dietary supplements may contain caffeine.

Levels of caffeine typically found in drinks and foods are listed in the following table obtained from the IFIC website (IFIC August 2002).