Since (subclinical) HCM can be demonstrated in up to 45% of ODM and long-term cardiovascular sequelae in offspring born after a type 1 diabetic pregnancy may already present in childhood [2
], we hypothesized that subtle changes in cardiac dimensions or function might also be present in ODM at school age. In this study, we are the first to show that systolic and diastolic function as well as cardiac dimensions in ODM at 7-8 years of age are completely normal and comparable with those in a control group of nondiabetic women.
In our cohort of ODM only three children (out of 30) were diagnosed with HCM after birth. However, in newborn ODM from our cohort echocardiography was only performed when HCM was clinically suspected, in contrast to the studies reporting higher prevalences of neonatal HCM [9
]. As fetal cardiac growth is promoted by binding of insulin to the cardiac insulin-like-growth-factor- (IGF-) 1 receptor, HCM is believed to resolve within weeks after birth due to normalization of fetal hyperinsulinaemia [30
]. Indeed cardiac dimensions and function parameters in the three children with previous neonatal HCM were normal at 7 years of age, but a larger prospective follow-up study of ODM with HCM should substantiate these results.
We previously showed that systolic blood pressure was significantly higher in ODM compared with controls [22
]. In this subgroup of children who underwent additional echocardiography, the difference in systolic blood pressure did not reach statistical significance, most likely due to the fact that the groups were smaller. Despite a slightly higher mean SBP in ODM there were no differences in left ventricular function parameters between controls and ODM jet. Larger follow-up studies are necessary to investigate whether the difference in systolic blood pressure persists throughout childhood and may have consequences for cardiac function in later life.
Previous studies have shown that offspring of diabetic women who were macrosomic at birth are at increased risk of developing overweight and other cardiovascular risk factors [3
]. Therefore, we investigated the possible influence of neonatal macrosomia on cardiac outcome in ODM. We found that neither cardiac dimensions nor cardiac function significantly differed between macrosomic ODM and those with an appropriate-for-date birth weight. As some studies have shown more cardiac alterations in macrosomic newborns of diabetic mothers when compared with macrosomic newborns of nondiabetic mothers [31
], we compared cardiac outcome of macrosomic ODM with that of macrosomic controls. No significant differences between those subgroups were found, indicating that neonatal macrosomia in ODM has no adverse effects on cardiac function at 7-8 years of age.
Extrapolating Freinkel's theory on “fuel-mediated teratogenesis,” which states that high glucose concentrations during diabetic pregnancy make the developing tissues in the offspring vulnerable to alterations later in life [33
], one might expect less favorable cardiovascular outcome in offspring of diabetic mothers with poorer glycemic control during pregnancy. However, maternal glycemic control during pregnancy did not significantly correlate with cardiac dimensions or function parameters in ODM at 7-8 years of age. It should be noted that maternal HbA1c may not be an accurate tool for the classification of level of glycemic control as it does not reflect the complexities of glycemic control in pregnant diabetic women [34
As we are the first to describe cardiac dimensions and function in ODM at school age, this study should be a valuable addition to previous studies on long-term effects of a diabetic pregnancy on the development in the offspring. A limitation of this study is the relatively small sample size. Larger, ideally prospective follow-up studies should substantiate our results.