High blood sugar during pregnancy associated with congenital heart defect

Washington: A study has observed that maternal diabetes can lead to fetal heart development of the child.

Congenital heart disease (CHD) is the most common birth defect, and even with remarkable advances in care, it remains the leading cause of non-infectious death in infants.

CHD is the result of a complicated interplay between genetic and non-genetic, or “environmental,” factors acting on the fetus. While the genetic contributors have become increasingly defined, the environmental factors are an important area of investigation. One of those environmental factors is maternal hyperglycemia.

A study, published in the Journal of Birth Defects Research, offers a “state of the science” look at the impact of maternal diabetes, and potential gene-environmental influences in that context, on fetal heart development.

“Many epidemiological studies have demonstrated a strong correlation between maternal diabetes and increased risk of CHD in babies born to affected mothers,” said Dr Garg, a researcher. “And many factors, including the type of diabetes, other environmental influences, and potentially certain genetic predispositions can influence which CHD subtypes are likely to develop.”

For example, type 1 and type 2 diabetes are linked with specific CHD subtypes. Babies born to mothers with type 1 diabetes had a greater association with conotruncal malformations and atrioventricular septal defects. Those born to mothers with type 2 diabetes had the highest risk of heterotaxy and left ventricular outflow tract obstructive malformations. Both types of maternal diabetes also increased the risk of other types of CHD in the infants, including right ventricular outflow tract obstructive malformations and atrial and ventricular septal defects, albeit to lower levels.

The gestational age at which the fetus is exposed to maternal diabetes is also important. Maternal diabetes before conception and during the first trimester is associated with diabetic embryopathy in the fetus, which affects the heart, great vessels, and neural tube. When maternal diabetes develops in the latter half of pregnancy, it is associated with fetal macrosomia, cardiomyopathy, increased incidence of perinatal complications and mortality.

Diabetes is a complex disease, with abnormal homeostasis of multiple components in metabolism that ultimately leads to the overall metabolic syndrome. Despite this complexity, hyperglycemia has been determined to be the primary teratogen in all forms of diabetes.