This study was done to test the belief that foods rich in polyphenols, especially flavonoids, consumed by mothers during the third trimester interfere with fetal heart ductal dynamics. Constriction of the ductus arteriosus before birth can harm the fetus and can cause pulmonary hypertension.
Patency of the ductus arteriosus, which stays open until birth, depends on prostaglandin production from arachidonic acid. Nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit prostaglandins and cause ductal constriction. Flavonoids are anti-inflammatory and inhibit prostaglandin production.
Flavonoids are a type of polyphenol found in herbal tea, grape and orange derivatives, dark chocolate, berries, green and black teas, olive oil, soy beans, berries, tomatoes, spinach, mate tea (Ilex paraguariensis,) resveratrol (from grapes and wine,) oranges, red apples and peanuts. The study used questionnaires to calculate flavonoid content from the USDA Database for the Flavonoid Content of Selected Foods. Catechins are the flavonoids in green tea and are 30-40% of solid green tea extract. Catechins have antioxidant and anti-inflammatory activity.
Fetuses whose mothers ate diets rich in polyphenols were compared to fetuses whose mothers ate diets poor in polyphenols by Doppler testing of heart ducts. Previous studies show constriction of the ductus arteriosus in fetuses from mothers who consumed significant amounts of polyphenols. This study shows increased ductal blood flow and large right ventricles even without ductal constriction. This changed with reduced maternal polyphenol use.
CONCLUSION: Fetuses exposed the most to polyphenols during the third trimester had abnormal ductus arteriosus dynamics. The authors believe that perinatal dietary warnings are indicated for polyphenol use, especially during the third trimester of pregnancy.
NOTE: Doppler testing tests blood flow by ultrasound. The ductus arteriosus blood vessel constricts and closes after birth.