Maternal restriction of polyphenols and fetal ductal dynamics in normal pregnancy: an open clinical trial.

Background: We have recently demonstrated reversal of fetal ductal constriction after dietary maternal restriction of polyphenol-rich foods (PRF), due to its inhibitory action on prostaglandin synthesis.

Objective: To test the hyphotesis that normal third trimester fetuses also improve ductus arteriosus dynamics after maternal restriction of polyphenols.

Methods: Open clinical trial with 46 fetuses with gestational age (GA) > 28 weeks submitted to 2 Doppler echocardiographic studies with an interval of at least 2 weeks, being the examiners blinded to maternal dietary habits. A validated food frequency questionnaire was applied and a diet based on polyphenol-poor foods (<30 mg/100 mg) was recommended. A control group of 26 third trimester fetuses was submitted to the same protocol. Statistics used t test for independent samples.

Results: Mean GA was 33 ± 2 weeks. Mean daily maternal estimated polyphenol intake (DMPI) was 1277 mg, decreasing to 126 mg after dietary orientation (p=0.0001). Significant decreases in systolic (SDV) and diastolic (DDV) ductal velocities, and RV/LV diameters ratio, as well as increase in ductal PI were observed [DSV = 1.2 ± 0.4 m/s (0.7-1.6) to 0.9 ± 0.3 m/s (0.6-1.3) (p = 0.018); DDV = 0.21 ± 0.09 m/s (0.15-0.32) to 0.18 ± 0.06 m/s (0.11-0.25) (p = 0.016); RV/LV ratio = 1.3 ± 0.2 (0.9-1.4) to 1.1 ± 0.2 (0.8-1.3) (p=0.004); ductal PI = 2.2 ± 0.03 (2.0-2.7) to 2.4 ± 0.4(2.2-2.9) (p = 0.04)]. In the control group, with GA of 32 ± 4 weeks, there were no significant differences in DMPI, mean SDV, DDV, PI and RV/LV ratio.

Conclusion: The oriented restriction of third trimester maternal ingestion of polyphenol-rich foods for a period of 2 weeks or more improve fetal ductus arteriosus flow dynamics and right ventricular dimensions.