You might have heard that caffeine isn't healthy in immoderate amounts during pregnancy. This is true, but the reason has nothing to do with the unborn baby's DNA structure -- there's no evidence that caffeine causes mutations. Instead, caffeine can interfere with an embryo's ability to thrive and a later fetus's ability to grow.
Caffeine
Caffeine is a stimulant compound that activates the sympathetic -- the "fight or flight" -- branch of your nervous system. It increases your heart rate, makes you feel more awake and increases your attention. It can also cross the placenta and induce similar effects in your developing child. Because caffeine crosses the placenta in some quantity, most obstetricians recommend limiting caffeine use during pregnancy.
Mutagenic Activity
In the mid-1900s, many scientific studies were designed to determine whether caffeine had potential as a mutagen or teratogen. A mutagen causes changes to DNA structure and mutation, while a teratogen causes birth defects. A 1973 article published in the scientific journal "Teratology" by Dr. John Mulvihill suggests that caffeine has a molecular structure that gives it potential as a mutagen. However, there's no real evidence that caffeine actually causes mutations in humans -- at least not in amounts that humans use routinely.
Miscarriage Concerns
Just because there's no evidence that caffeine will cause mutations to your unborn baby's DNA doesn't mean it's safe, however. In their book "You: Having A Baby," Drs. Michael Roizen and Mehmet Oz explain that caffeine use increases your risk of a miscarriage in early pregnancy. The mechanism for this isn't known, but it's most likely to occur in women who drink moderate to large quantities of caffeine each day.
Late Pregnancy
Later in pregnancy, caffeine isn't likely to induce miscarriage, note Roizen and Oz. It may, however, restrict fetal growth, leading to low birth weight. This, in turn, predisposes your baby to additional health problems. Roizen and Oz recommend avoiding or limiting caffeine during pregnancy. Keep your caffeine consumption below 300 mg per day to help prevent health problems in your unborn baby.
References
- "Teratology"; Caffeine as teratogen and mutagen; J. Mulvihill; 1973
- "You: Having A Baby"; Michael Roizen, M.D. and Mehmet Oz, M.D.; 2009
