I devote a fair proportion of my practice to women’s health and infertility, so I was surprised to learn from a patient recently about green tea and pregnancy that I didn’t know.

 I am a strong proponent of regular green tea consumption. Green tea contains compounds that help people to breathe easier, relax, prevent cancer cells from multiplying, and inhibit cancer cells’ ability to invade healthy tissue. Not bad from a simple drink. Maybe this is why it has been consumed in Asia for thousands of years, with apparent excellent health results.

 I didn’t think there was a downside to green tea. But I learned that there is, or rather that there might be. As it turns out, the compounds that inhibit cancer cell multiplication do so by interfering with the body’s ability to use the b-vitamin folic acid. Folic acid is a staple in every pregnant woman’s multivitamin, as a deficiency in folic acid can lead to neural tube defects, like spina bifida, in her baby. By interfering with folic acid in the body, green tea could theoretically increase the chances of these birth defects. Therefore, I have started to recommend to women currently pregnant or wishing to get pregnant that they avoid green tea.

Black tea does not have the same effect and is safe to drink in moderate quantities. So is coffee. The green tea effect has nothing to do with caffeine.

If you are a green tea drinker and you are pregnant, don’t panic. I actually found no published medical study that demonstrates an increase in neural tube defects in green tea drinkers. The heaviest green tea drinkers do have lower blood levels of folic acid than those who don’t drink green tea. I did read in the abstract to one paper the following sentence: “The association between folate and the consumption of green tea…may be useful to clarify the mechanism which links adverse perinatal outcomes and tea consumption.” So this author makes a statement as though there is an established link. Again, I found not a single published study that actually demonstrated such a link. It is a theoretical risk only.

Nevertheless, when it comes to your baby, why take risks? In my practice, where women are sometimes conceiving after years of inability to do so, we try to tip the scales in favor of a healthy outcome however possible. So abstain from green tea during pregnancy…but start drinking it again after your baby is born!