Birth Weight and Cardiac Structure in Children

Abstract

OBJECTIVE. Epidemiologic studies have shown associations between impaired fetal growth and risk for coronary heart disease in adults. The underlying mechanisms are unknown. We investigated whether restricted intrauterine growth affects cardiac structure.METHODS. We performed echocardiography on 216 9-year-old children who were measured previously at birth. The diameter of the coronary left and right main branches was derived from the widest dimension; total coronary artery diameter was calculated by adding the diameters of the left and right coronary arteries. Aortic root diameter, left atrial diameter, left ventricular diameter, left ventricular outflow tract diameter, and left ventricular mass were measured.RESULTS. On average, children who had weighed less at birth had a smaller total coronary artery diameter, aortic root diameter, and left ventricular outflow tract diameter after adjustment for gender, gestational age, current height and weight, and maternal height and prepregnant weight. For each SD increase in birth weight, total coronary diameter rose by 0.10 mm, log aortic root diameter rose by 1.5%, and log left ventricular outflow tract diameter rose by 1.6%.CONCLUSION. Impaired fetal growth may have long-term effects on cardiac structure. This may help to explain why adults whose birth weight was low are at greater risk for coronary heart disease. [1][2][3][4][5] The mechanisms that underlie this relation are unclear. One possibility may be that poor fetal growth has effects on cardiac structure that persist into childhood and beyond, increasing the risk for coronary artery disease.We used echocardiography to examine a group of 216 children who were aged 9 years and had been measured at birth. Our aim was to investigate the relation between birth weight and cardiac chamber, aortic root, and coronary artery diameters. METHODSThe mothers of the children in this study all had taken part in an earlier study of nutrition during pregnancy between April 1992 and June 1993. White women who were aged 16 years or more and had singleton pregnancies of Ͻ17 weeks' gestation were recruited during their first visit to the midwives' antenatal booking clinic at the Princess Anne Maternity Hospital in Southampton, UK; women who had diabetes and those who had undergone hormonal treatment to conceive were excluded. There were routine obstetric data about the pregnancy and delivery, and anthropometric data on the child were collected at birth. Gestation was estimated from menstrual history and scan data. 6 In total, 559 children were followed up to the age of 9 months, and these children form the sampling frame for this study.When the children approached 9 years of age, we asked the Community Pediatric Service in Southampton to write to their parents with an invitation to take part in an additional follow-up study to investigate the effect of early growth on the structure and function of the heart and blood vessels, on cognitive function, and on bone mass. We chose to study the children at 9 years of age because ...

Evidence of Arteriolar Narrowing in Low-Birth-Weight Children

“…We have previously shown in adults that narrower retinal arterioles predict by many years the onset of clinical hypertension, 19 -21 diabetes mellitus, 31 and coronary heart disease, 22,23 which highlights the contribution of microvascular disease to these disorders. The present results thus complement and extend to small arterioles the substantial existing literature documenting associations of low birth weight with abnormalities of the large arteries such as reduced aortic dimension 14 and compliance, 13 increased wall thickening, 32 narrower coronary arteries, 33 and increased carotid atherosclerosis. 15,16 Smaller head circumference and shorter birth length are associated with higher blood pressure 9,34 and subsequent cardiovascular disease in adulthood, 10,35 and the present study is among the first, and the largest to date, to report associations of these birth parameters with structural abnormalities of the microcirculation.…”

Low Birthweight Is Associated With Narrower Arterioles in Adults

“…Low birthweight is known to be associated with narrower aortic, common carotid, 35 and coronary arteries. 10 Our study now shows that low birthweight is also associated with narrower resistance arterioles in addition to arteries. Importantly, we have previously demonstrated that retinal arteriolar narrowing is linked to a number of hypertension-related genes, 36 and prospectively predicts the development of hypertension 16,18 -20 and cardiovascular events such as coronary heart disease and stroke.…”

“…8 This led to the concept that fetal "programming" during critical phases of development in utero 2,9 may result in long-term structural changes in the vascular system. 10,11 However, the underlying vascular mechanisms are not known, but their elucidation is clearly important in further understanding the etiology of hypertension and cardiovascular disease. 12 It has been hypothesized that low birthweight may have an adverse impact on microcirculatory structure, 13,14 possibly initiating a cascade of arteriolar narrowing and vasoconstriction that ultimately leads to the development of hypertension.…”

Left Ventricular Mass and Geometry in Adolescence

“…2,19,20 Discrepancy in the results may in part be explained by the smaller study cohorts and a wider age range in the previous studies. In a recent population-based prospective cohort study, LVM at the age of 2 years, however, increased with increasing birth weight in line with our results.…”