Yes, excessive green tea consumption may increase the risk of neural tube defects (NTDs) in pregnancy, primarily because catechins in green tea can reduce folic acid absorption, which is essential for proper fetal neural tube development.
Evidence and Mechanism
- Studies, including large-scale epidemiological research, have found that mothers who drank more than three cups of green or black tea per day during early pregnancy had lower serum folate levels and a higher risk of neural tube defects compared to non-tea drinkers. The risk is especially elevated in the critical first trimester, when the neural tube is closing.
- Green tea’s catechins and specific antioxidants (e.g., EGCG) inhibit intestinal folic acid absorption and may also interfere with enzymes necessary for folate’s action in cell development.
- Moderate intake (one cup per day) does not present a significant risk, especially if pregnant individuals take prenatal folic acid supplements.
Recommendations
- Limit green tea and other tea intake to one or two cups per day and ensure adequate folic acid supplementation before and during the first trimester.
- Heavy tea drinking (three or more cups/day) should be avoided in early pregnancy due to its possible antifolate effects and increased NTD risk.
Summary Table: Green Tea & Neural Tube Defect Risk
| Aspect | Risk Explanation |
| Folate absorption | Green tea blocks folic acid uptake |
| Quantity-related risk | >3 cups/day linked to higher NTD risk |
| Risk window | Highest in first trimester (neural tube closure) |
| Supplementation mitigating | Prenatal folic acid can offset moderate tea intake |
Excess green tea in pregnancy can increase the risk of neural tube defects by hindering folic acid absorption. Stick to low-moderate intake and take prenatal vitamins to support fetal development.
