Elevated Blood Glucose Levels may pose Heart Defect Risk to Infants

Elevated blood glucose levels during early pregnancy may increase the risk of congenital heart disease in infants even if the mother is nondiabetic.

Highlights

Elevated glucose values during early pregnancy can be associated with increased risk for congenital heart disease in babies
Early recognition of the defects prenatally can improve patient outcomes as both the mother and baby can receive specialized care
Congenital heart risk was found to be elevated to 8 percent for every 10 milligrams per deciliter increase in blood glucose level

Higher blood sugar levels during the first trimester of pregnancy can increase the chances of congenital heart disease in infants born to nondiabetic mothers. The findings of this study are published in The Journal of Pediatrics.

For many years, physicians have known that women with diabetes face an increased risk of giving birth to babies with heart defects. Some studies have also suggested a link between nondiabetic mothers' blood sugar levels and babies' heart defect risk. However, the new study is the first to examine this question in the earliest part of pregnancy, when the fetal heart is forming.

Congenital Heart Defects - Causes, Symptoms, Diagnosis & Treatment
Congenital heart defects are structural abnormalities of the heart present at birth, and that affect blood flow through the heart and to the rest of the body.

‘Blood glucose level check just before the period of heart development (first trimester) may predict congenital heart disease in infants of expectant mothers who do not have diabetes.’

"Most women who have a child with congenital heart disease are not diabetic," said the study's senior author, James Priest, MD, assistant professor of pediatric cardiology. "We found that in women who don't already have diabetes or develop diabetes during pregnancy, we can still measure risk for having a child with congenital heart disease by looking at their glucose values during the first trimester of pregnancy."

The study's lead author is Emmi Helle, MD, Ph.D., an affiliate in pediatric cardiology and former postdoctoral scholar.

One challenge associated with conducting the research was the fact that maternal blood glucose is not routinely measured in nondiabetic pregnant women. Instead, women typically receive an oral glucose tolerance test halfway through pregnancy to determine whether they have gestational diabetes, but this test is performed well after the fetal heart has formed.

Patent Ductus Arteriosus
Patent Ductus Arteriosus is a congenital defect of the heart where the fetal passage between pulmonary artery and aorta remains open and causes excess pulmonary blood flow.

The research team studied medical records from 19,107 pairs of mothers and their babies born between 2009 and 2015. The records included details of the mothers' prenatal care, including blood test results and any cardiac diagnoses made for the babies during pregnancy or after birth.

Infants with certain genetic diseases, those born from multiple pregnancies and those whose mothers had extremely low or high body-mass-index measures were not included in the study. Of the infants in the study, 811 were diagnosed with congenital heart disease, and the remaining 18,296 were not.

Truncus Arteriosus - Types, Risk Factors, Clinical Features, Management & Prevention
Truncus arteriosus is a birth defect in which there is only one main artery in the heart that conveys blood both to the lungs and to the rest of the body.

The scientists analyzed blood glucose levels from any blood sample collected from the mothers between four weeks before the estimated date of conception and the end of the 14th gestational week, just after the completion of the first trimester of pregnancy. These early blood glucose measurements were available for 2,292, or 13 percent, of women in the study. The researchers also looked at the results of oral glucose tolerance tests performed around 20 weeks of gestation, which were available for 9,511, or just under half, of the women in the study.

After excluding women who had diabetes before pregnancy or who developed it during pregnancy, the results showed that the risk of giving birth to a child with a congenital heart defect was elevated by 8 percent for every increase of 10 milligrams per deciliter in blood glucose levels in the early stages of pregnancy.

Diabetes - Oral Hypoglycemic Agents and Glycemic Control
Glycemic control in type 2 diabetes is achieved with oral diabetic medications. Combination drugs and insulin therapy is sometimes required.

The next step in the research is to conduct a prospective study that follows a large group of women through pregnancy to see if the results are confirmed, Priest said.

If researchers see the same relationship, it may be helpful to measure blood glucose early in pregnancy in all pregnant women to help determine which individuals are at greater risk for having a baby with a heart defect, he said.

"We could use blood glucose information to select women for whom a screening of the fetal heart could be helpful," Priest said, adding that modern prenatal imaging allows for detailed diagnoses of many congenital heart defects before birth. "Knowing about defects prenatally improves outcomes because mothers can receive specialized care that increases their babies' chances of being healthier after birth."

The work is an example of Stanford Medicine's focus on precision health, the goal of which is to anticipate and prevent disease in the healthy and precisely diagnose and treat disease in the ill.

References

Emmi I.T. Helle, Preston Biegley, Joshua W. Knowles, Joseph B. Leader, Sarah Pendergrass, Wei Yang, Gerald R. Reaven, Gary M. Shaw, Marylyn Ritchie, James R. Priest. First Trimester Plasma Glucose Values in Women without Diabetes are Associated with Risk for Congenital Heart Disease in Offspring, Journal of Pediatrics (2017). DOI: http://dx.doi.org/10.1016/j.jpeds.2017.10.046

Source-Eurekalert