It is unclear whether tea consumption affects the fetus. Most epidemiologic studies include important confounders, especially socioeconomic status, which may influence tea or another beverage intake as well as pregnancy outcome. This review found insufficient evidence to conclude possible adverse effects of tea on pregnancy outcomes. However, it does raise questions about the safety of very high levels of tea consumption during pregnancy.
part of their daily routine
Tea is a popular drink all over the world, and many pregnant women enjoy tea as part of their daily routine. Some believe that tea has health benefits for both the mother and the baby, while others are concerned that too much tea may be harmful to the baby. So what does the evidence show?
The medical evidence of antioxidant compounds
Catechins are a group of antioxidant compounds found in all tea leaves. Several studies have measured the level of these compounds in pregnant women or their umbilical cord blood, but most were small and not well-designed. Of 19 larger studies, only five included appropriate controls for potential confounders such as socioeconomic status, smoking, and alcohol consumption. Of these five studies only two found a correlation between catechins in the mother or unborn child and one of them did not adjust for the mother’s age, which is a possible predictor of both tea drinking and pregnancy outcome.
A study from Peru showed a potential benefit of tea drinking on iron-deficiency anemia during pregnancy. However, the study was small and not well-designed.
pregnant women who enjoy drinking tea
There is no clear evidence that drinking tea has any adverse effects on pregnant women or their babies. However, more research is needed to confirm this. Some studies have shown a correlation between catechins in the mother or unborn child and tea drinking, but these studies are too small to be reliable.
High doses of green tea extract (>5 g/d) might reduce insulin sensitivity in pregnant women with gestational diabetes mellitus (diabetes during pregnancy). However, this was only found in one study which used high-dose green tea extract (>5 g/d) and was not designed to look at this question.
In one study from the UK, women who used green tea supplements during pregnancy were more likely to have a baby with a cleft lip or palate than those who did not use green tea supplements. Importantly, the level of catechins in these supplements was high (5.8 mg/d).
Overall, the evidence is inconclusive and more research is needed. However, it is probably safest to drink moderate amounts of tea during pregnancy – around two cups per day.