Aortic isthmus blood flow in fetuses of diabetic mothers.

OBJECTIVE: To test the hypothesis that the aortic isthmus flow index (IFI) is lower in fetuses of diabetic mothers than in fetuses of nondiabetic mothers. STUDY DESIGN: We performed a cross-sectional observational study to assess the IFI in fetuses, with (n = 13) and without (n = 37) myocardial hypertrophy, of mothers with diabetes mellitus and in fetuses of nondiabetic mothers (n = 23). Analysis of variance and Tukey test were used to assess differences among the groups. RESULTS: There were no differences in maternal or gestational age among the groups. In fetuses of diabetic mothers, the mean IFI in fetuses with myocardial hypertrophy was 1.19 ± 0.06, and in fetuses without it was 1.18 ± 0.09. The mean IFI in fetuses of nondiabetic mothers was 1.32 ± 0.07 (P < 0.001). CONCLUSIONS: The IFI in fetuses of diabetic mothers is lower than in fetuses of nondiabetic mothers, possibly as a result of a decreased left ventricular compliance.

Influence of fetal respiratory movements on left atrial functional status.

OBJECTIVE: Because fetal respiratory movements increase left ventricular compliance, we hypothesized that the left atrial shortening fraction increases during fetal respiratory motions. METHODS: A group of 26 normal fetuses with gestational ages between 28 and 38 weeks were assessed in a prospective cross-sectional study. Left atrial telesystolic and presystolic diameters were measured during apnea and after five consecutive respiratory movements. Left atrial shortening fraction was obtained by the ratio: [maximal left atrium diameter (telesystolic) - minimal left atrium diameter (presystolic)]/maximal left atrium diameter (telesystolic). The mean of three measurements were considered. Two-tailed Student's t-test was used. RESULTS: Mean gestational age was (mean ± SD) 30.7 ± 2.8 weeks. Mean left atrial telesystolic diameter in apnea was 10.6 ± 0.7 mm and during respiratory movements it was 10.5 ± 1.1 mm (p = 0.98). Presystolic left atrial diameter was 5.2 ± 0.1 mm in apnea and 4.4 ± 1.3 mm during respiratory movements (p < 0.001). Left atrial shortening fraction was 0.50 ± 0.05 in apnea and 0.58 ± 0.13 during respiratory movements (p < 0.001). CONCLUSION: Left atrial shortening fraction is higher during respiratory movements as a result of increased left ventricular compliance and consequent optimization of left atrial functional status.

Mobility of the Septum primum does not depend on the foramen ovale diameter in normal fetuses.

OBJECTIVE: To test the hypothesis that a correlation exists between the maximum foramen ovale diastolic diameter and the excursion index (EI) of the septum primum in normal fetuses. METHODS: One hundred and two normal fetuses with gestational ages ranging from 20 to 40 weeks were submitted to echocardiography. The foramen ovale diameter and the "maximal excursion" of the septum primum were measured in a 4-chamber view. The data were analyzed by Pearson's correlation coefficient. RESULTS: The mean foramen ovale (FO) diameter was 5.06 +/- 1.29 mm; the maximal excursion of the septum primum was 5.42 +/- 1.41 mm; the left atrium diameter 11.47 +/- 2.76 mm; the septum primum "excursion index" was 0.48 +/- 0.09. Mean FO/EI ratio was 11.35 +/- 3.94 mm. No FO/EI correlation (r = -0.03) existed, and a weak foramen ovale/left atrium correlation (r = 0.31) was observed, as well as a weak foramen ovale/excursion of septum primum correlation (r = 0.21). CONCLUSION: Septum primum mobility does not depend on the foramen ovale diameter in normal fetuses, suggesting that the modifications of its diastolic displacement is not influenced by the size of the interatrial opening.

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.

Myocardial hypertrophy and dysfunction in maternal diabetes.

Diabetes in pregnancy, both pre-gestational and gestational, is a frequent cause of fetal myocardial hypertrophy, partly due to fetal hyperinsulinism. In fetal life, cardiac function may be impaired, especially during diastole, as a result of decreased left ventricular distensibility and altered left atrial dynamics secondary to myocardial hypertrophy. In neonates, the hypertrophy is a transient disorder, with spontaneous regression of the increased myocardial thickness during the first months of life. Nevertheless, cardiac hypertrophy may be associated with neonatal cardiomegaly and respiratory distress secondary to poor left ventricular compliance. The development of a number of new echocardiographic parameters discussed in this article, and primarily based on the pathophysiological consequences of myocardial hypertrophy, highlight an area of research priority: the assessment of diastolic function in fetuses of diabetic mothers with (and without) myocardial hypertrophy. A score for grading the severity of fetal diastolic dysfunction in these fetuses is proposed.

New insights on fetal ductal constriction: role of maternal ingestion of polyphenol-rich foods.

Fetal ductus arteriosus constriction is a clinical disorder that occurs as a result of inhibition of the prostaglandin synthesis pathway, and has long been associated to maternal intake of nonsteroidal antiinflammatory drugs in late pregnancy. As a consequence of an increased right ventricular pressure, with tricuspid regurgitation and heart failure, there is a risk for the development of neonatal pulmonary artery hypertension. This article reviews the basic knowledge of the mechanisms involved in this important disorder. Clinical and experimental evidence that maternal consumption of polyphenol-rich substances, such as herbal teas, orange and grape juice, chocolate, and others, may interfere with fetal ductus arteriosus dynamics are discussed. Preventive measures to avoid fetal ductal constriction in the third trimester of pregnancy are discussed, including the possible need to change maternal dietary orientation, aiming to limit ingestion of foods with high concentrations of polyphenol-rich substances.