Women who are trying to conceive often wonder whether there's something they're eating that might be negatively impacting their ability to get pregnant. While small amounts of caffeine aren't likely to impact your fertility, there are several reasons you might want to avoid large quantities of caffeinated foods and beverages.
Caffeine is a stimulant that falls into the same category of chemicals as theobromine, which is the stimulant compound found in chocolate. It's a sympathomimetic, meaning it stimulates the "fight or flight" neural response, or leads to effects similar to those of adrenaline. When you consume caffeine, your attention increases, you feel more awake and your heart rate increases. If you consume too much caffeine, you may feel very jittery and have trouble focusing or sleeping.
If you're trying to get pregnant, your health is of particular importance. A woman's body is designed such that you are most fertile if you're most prepared to carry a baby to term--this is why very underweight and very overweight women often have trouble conceiving. Further, if you're vitamin deficient, you may have difficulty conceiving. A 2009 study published in the "Journal of Bone and Mineral Research" found that caffeine can decrease absorption of vitamin D, leading to calcium imbalance. As such, pregnant women might want to avoid caffeine so as to avoid potential vitamin D deficiency.
Risk of Miscarriage
Drs. Michael Roizen and Mehmet Oz, in their book "You: Having A Baby," note that researchers have found conflicting effects of caffeine on early pregnancies. Some studies suggest that caffeine has little effect upon early pregnancy viability, while other studies show that rate of miscarriage is much higher in habitual coffee drinkers who consume large quantities of caffeine each day. To be safe, Drs. Roizen and Oz recommend limiting yourself to a cup or two of coffee a day.
If you're interested in getting pregnant, you probably know that once you achieve your goal, you'll start losing sleep--literally. Insomnia is a common complaint during pregnancy, and new mothers face months of being awakened regularly to feed their new baby. Since caffeine can lead to difficulty sleeping or sleep disturbance, you might want to start dialing back your caffeine use during the preconception months, so that you can maximize your sleep while you still can.
Dr. Miriam Stoppard, in her book "Conception, Pregnancy and Birth," notes that most of the research on caffeine suggests that, unlike alcohol, caffeine tends to have an "all or nothing" effect upon a pregnancy. That is, rather than causing birth defects, caffeine either does no harm or causes miscarriage. Because you may be pregnant for many weeks before realizing you're pregnant, and because the first weeks of pregnancy are the most sensitive in terms of miscarriage risk, Dr. Stoppard advises very conservative caffeine use while you're trying to conceive.