Evaluation of Abdominal Fetal Electrocardiography in Early Intrauterine Growth Restriction

Fetal growth restriction (FGR) affects 5% to 10% of newborns and is associated with increased cardiovascular mortality in adulthood. The most commonly accepted hypothesis is that fetal metabolic programming leads secondarily to diseases associated with cardiovascular disease, such as obesity, diabetes mellitus, and hypertension. Our main objective was to evaluate the alternative hypothesis that FGR induces primary cardiac changes that persist into childhood. Within a cohort of fetuses with growth restriction identified in fetal life and followed up into childhood, we randomly selected 80 subjects with FGR and compared them with 120 normally grown fetuses, matched for gender, birth date, and gestational age at birth. Cardiovascular assessment was performed in childhood (mean age of 5 years). Compared with control subjects, children with FGR had a different cardiac shape, with increased transversal diameters and more globular cardiac ventricles. Although left ejection fraction was similar among the study groups, stroke volume was reduced significantly, which was compensated for by an increased heart rate to maintain output in severe FGR. This was associated with subclinical longitudinal systolic dysfunction (decreased myocardial peak velocities) and diastolic changes (increased E/E' ratio and E deceleration time). Children with FGR also had higher blood pressure and increased intima-media thickness. For all parameters evaluated, there was a linear increase with the severity of growth restriction. These findings suggest that FGR induces primary cardiac and vascular changes that could explain the increased predisposition to cardiovascular disease in adult life. If these results are confirmed, the impact of strategies with beneficial effects on cardiac remodeling should be explored in children with FGR.

Intrauterine growth retardation (IUGR) is mainly due to a pathologic slow-down in the fetal growth pace, resulting in a fetus that is unable to reach its growth potential. IUGR frequency will vary depending on the discrimination criteria adopted. It is extremely important to use local or national fetal growth graphs in order to avoid some confounding factors. IUGR incidence in newborns would be between 3% and 7% of the total population. In our experience it is 5.13% a figure similar to the one obtained by other authors but with a progressively higher incidence during the last decade. There are multiple maternal factors that can generally be grouped into constitutional and general factors given that they affect age, weight, race, maternal cardiac volume, etc, socioeconomic factors with key incidence in the mother's nutrition level, where a poor maternal nutrition level would be the key factor in this group. We have evaluated multiple factors as possible contributors to the IUGR risk: race, parents' age, mother's height (cm), mother's birth weight and before pregnancy (kg), ponderal gain and blood pressure during pregnancy, and previous SGA newborns. Socioeconomic factors like social class, parents' profession, habitual residence, salary, immigration, and diet were also evaluated. We also included variables such as total daily working time and time mothers spent standing up, daily sleeping time (hrs), stress self-perception test at work and primiparity age. Toxic factors during pregnancy: tobacco (active and passive), alcohol, drugs and coffee consumption. Fetal or utero-placental factors were considered. In our study, the most significant etiologic factors were: Active and passive tobacco consuming, mother's stress level, increase of total months worked during pregnancy, total daily working hours and time mothers spent standing up and finally, the parent's height. Our data support the main objective of reducing the incidence of SGA newborns after IUGR by fighting against tobacco from all fields, including the passive smoking habit, and improving the laboral conditions of the pregnant mother, lowering the number of daily hours worked, the physical activity and trying to avoid and to cope with stressful situations.

The purpose of this study was to assess cardiac function and cell damage in intrauterine growth-restricted (IUGR) fetuses across clinical Doppler stages of deterioration. One hundred twenty appropriate-for-gestational-age and 81 IUGR fetuses were classified in stages 1/2/3 according umbilical artery present/absent/reversed end-diastolic blood flow, respectively. Cardiac function was assessed by modified-myocardial performance index, early-to-late diastolic filling ratios, cardiac output, and cord blood B-type natriuretic peptide; myocardial cell damage was assessed by heart fatty acid-binding protein, troponin-I, and high-sensitivity C-reactive protein. Modified-myocardial performance index, blood B-type natriuretic peptide, and early-to-late diastolic filling ratios were increased in a stage-dependent manner in IUGR fetuses, compared with appropriate-for-gestational-age fetuses. Heart fatty acid-binding protein levels were higher in IUGR fetuses at stage 3, compared with control fetuses. Cardiac output, troponin-I, and high-sensitivity C-reactive protein did not increase in IUGR fetuses at any stage. IUGR fetuses showed signs of cardiac dysfunction from early stages. Cardiac dysfunction deteriorates further with the progression of fetal compromise, together with the appearance of biochemical signs of cell damage.