Maternal consumption of polyphenol-rich foods in late pregnancy and fetal ductus arteriosus flow dynamics

Abstract

We read with interest the article by Zielinsky et al. 1 , and we have some questions about the study methods and conclusions.In this paper, Zielinsky et al. 1 show alterations in ductal dynamics in fetuses exposed to polyphenol-rich foods and argued that maternal consumption of polyphenol-rich food is a risk factor for ductal constriction.Our first concern is related to the study design: was it a prospective study or a transversal study? The relative risks were adjusted for gestational age?Although the paper says: 'Pregnant women with systemic abnormalities or taking any medicines were excluded from the study', what about other confounding factors? Were the patients asked about smoking and illicit drug use that could also amend the echocardiography parameters? Some other important factors can also modify the fetal echocardiography during the pregnancy as urinary tract infection, diabetes, asthma or vaginal bleeding, with potentially harmful consequences in the neonatal period, such as pulmonary hypertension. Other confounding factors such as education, race or ethnicity, fetal gender and prepregnancy body mass index (BMI) could also affect the results. 2 Mean maternal BMI is described as 28.13±3.00 kg/m 2 , and the literature shows that persistent pulmonary hypertension of the newborn occurs in 15.5% in women with BMI >27 kg/m 2 and 7.2% for those with BMI <20 kg/m 2 . We question whether both groups presented similar BMI values.We calculated the effect size of mean peak systolic velocity as 1.61 (1.20-2.01), mean diastolic velocity was 1.27 (0.87-1.65) and mean right-to-left ventricular dimensions ratio (RV/LV) ratio was 1.39 (0.99-1.78), and although it seems a large effect, these variations do not have clinical relevance. Other point is the determination of the cutoff points: fetal systolic ductal velocity >0.85 m/s, diastolic velocity >0.15 m/s and RV/LV >1.1. Have they been determined by an receiver-operator characteristic curve with the maternal consumption of polyphenol-rich food? Would it not be interesting to use the known ultrasound parameters as shown in users of nonsteroidal anti-inflammatory drugs 3,4 with constrictive effect on the fetal ductus? We really think it is extremely important to follow-up the newborns in neonatal life to verify the real impact of these findings. The modifications in sonographic parameters and the other known risk factors may suggest a need for monitoring and intervention during antenatal period.Although differences were founded in mean diastolic velocity and mean diastolic velocity between the groups, both values are in the normal range. Previous reports suggest that a peak systolic velocity of >1.4 m/s and a diastolic peak flow velocity >0.35 m/s are suggestive of ductal constriction. 5 Huhta et al. 6 described the maximum systolic velocity ranged from 50 to 140 cm/s, with a mean of 80 cm/s and normal ductal velocity in diastole ranged from 6 to 30 cm/s in >20 weeks fetuses. This fact does not permit to state that 'changes in perinatal dietary orientation are warranted'...

Response to Galão et al

“…I thank you for giving me the opportunity to comment on the letter by Galão et al 1 regarding our article published in the Journal of Perinatology. 2 As Galão et al state, we have demonstrated alterations in ductal dynamics when normal fetuses were exposed to a high maternal intake of polyphenol-rich foodsFabove the 75th centile for our populationFand we indeed do hypothesize that these alterations may be a risk factor for ductal constriction, even though this issue was not the object of the present investigation.…”