High blood sugar in pregnant women can lead to heart problems in children

Lowering blood sugar levels before pregnancy may decrease the risk of having a baby born with congenital heart disease or a heart defect, a new study shows.

It’s known that pregnant women with gestational diabetes, and pregestational diabetes — which include both Type 1 and Type 2 diabetes — are at greater risk of delivering a baby with heart issues.

But a study published in The Journal of Pediatrics nearly three months ago shows alarming evidence that women who have elevated blood sugar as early as their first trimester, who aren’t diabetic, risk having a baby born with heart problems.

“The heart develops very early — between two and six weeks — by seven weeks the fetal heart is completely formed,” said Dr. Sethuraman Swaminathan, a pediatric cardiologist at the University of Miami Hospital and at Jackson Health.

“There is some effect on the high glucose level of the mother to the embryo,” he said, noting that high sugar levels from the mother are transferred to the embryo. “The high sugar in the embryo affects how the genes are expressed, affecting the way the heart develops.”

Dr Sethuraman Swaminathan UHealth

Dr. Sethuraman Swaminathan


A fasting sugar level less than 100 mg/dL is ideal, and shouldn’t exceed 120 mg/dL (two hours) after eating, he said.

Congenital heart defects are the most common birth defects, and affect nearly 1 percent of births per year in the United States — or about 40,000 births, according to the Centers for Disease Control and Prevention. About 25 percent of babies with congenital heart defects need surgery or other procedures in their first year of life.

In most cases, when a baby is born with a heart defect, there is no known reason for it, and depending on the extent of the defect, it may not pose a problem until later on in life.

Such was the case of 16-year-old Ariana Baserio, of Pembroke Pines, who was diagnosed at 6 months old with dilated cardiomyopathy, a condition in which the left ventricle, the heart’s main pumping chamber, is enlarged and weakened, hindering her heart’s ability to pump blood.

Her mother, Adriana Pazmin, says that although Ariana has been on heart medication all her life, it was stomach issues that led her to take her daughter to the doctor.

“She showed no symptoms of heart issues — no fatigue or shortness of breath,” said Pazmin, of her daughter.

But Ariana’s heart was deteriorating, causing her lungs to fill up with fluids that were dripping into her abdomen area.

“She was getting sick. She was getting paler and paler. She started throwing up,” Pazmin said.

Ariana became Joe DiMaggio Children’s Hospital’s 32nd heart transplant patient last September, and she was the first pediatric patient at the hospital to be implanted with a small battery-operated ventricular assist device, called HeartWare.

“Growing up, Ariana was always weaker,” her mother said. “She was developmentally delayed. It took her awhile to reach her milestones. She also has autism, which makes it even more challenging.”

Children with congenital heart disease are at increased risk of having developmental disorders or disabilities or developmental delays, according to the American Heart Association.

“Congenital heart disease is not created equal,” said neonatologist Dr. Saima Aftab, director of the Fetal Care Program at Nicklaus Children’s Hospital. “Even the mildest form of congenital heart disease increases your risk of learning problems.”

Dr Saima Aftab Nicklaus Childrens Hospital

Dr. Saima Aftab

Nicklaus Children’s Hospital

Babies who carry the highest risk for neurodevelopmental issues, she said, are those who suffer from significant congenital heart disease, those whose heart condition is paired with a genetic problem, or those who remained “blue” for some time due to a heart malformation that prevents the baby’s blood from being fully oxygenated.

“In the past six years there’s been an overwhelming amount of information gathered from studies which shows a significant risk of learning disabilities or developmental impairment in babies that have congenital heart disease,” she said.

The Fetal Care Program at Nicklaus provides pre-natal diagnostic testing, pre-natal genetic testing, fetal echocardiograms, counseling and consultations for families.

“The Fetal Care Program came together because there was a huge need in the community for women who have high-risk babies with heart problems and other congenital problems to get high-level testing done,” said Aftab.

Nicklaus is not allowed to deliver babies on campus, as it doesn’t treat adults. Babies born with critical health problems get airlifted there immediately after birth for surgery or to receive care in the cardiac ICU, she said.

A new Fetal Care Center at Nicklaus is underway.

“It’s specifically for babies who need surgery immediately after birth, where any delay in transfer could be life threatening,” Aftab said. “By the end of this year or the beginning of next year, we’ll be able to deliver these high-risk babies on campus.”

Aftab said the findings associating the risk of babies being born with congenital heart disease to women with high blood sugar can do much to benefit women before they conceive.

“If it bears true, than we found a potentially preventable cause of congenital heart disease,” she says. “We may have something that we can actually do about it — women may need to get their blood sugars checked more frequently. Maybe there’s dietary adjustments that can be recommended that would normalize it to lower that risk.”

She and Swaminathan recommend that women who are planning on getting pregnant get a hemoglobin A1c (HbA1c) test done, which reads a person’s average level of blood sugar from the past two to three months.

Both doctors also say that planning pregnancies can reduce the risk of having a baby with a congenital heart defect. That way, there’s time to review one’s family history to see if there’s an increased risk of heart disease, and testing for pre-diabetes, diabetes and high blood pressure can be done, as well as reviewing any medications, which may affect the developing heart.

Gestational diabetes and excessive weight gain during pregnancy often correspond with giving birth to a large baby, which carries risks for both the mother and her offspring, including hypoglycemia (low blood sugar) of the baby after delivery.

Large for Gestational Age (LGA) babies can often become an obese child, which raises the risk of heart disease, even before puberty.

“Children are already developing plaques in some of the large arteries in their bodies,” said Dr. Frank Scholl, the chief of Pediatric and Congenital Heart Surgery at Joe DiMaggio Children’s Hospital.

“I’ve had 8-, 9-, 10-year-old children who already have atherosclerotic disease in their aorta,” he says, “which is what we think about adults and older people having.”

Early testing and management of blood sugar during pregnancy may help decrease the risk of congenital heart disease in newborns.

Women planning to conceive should talk with their doctors to review family history and medications, and get bloodwork done to see whether there are issues that can be corrected before conception.

Pregnant women should get a fetal echocardiogram test (often done in the second trimester) to screen for any major congenital cardiac anomalies in their developing baby.

A hemoglobin A1c (HbA1c) test reads a person’s average level of blood sugar from the past two to three months. If the levels are too high, steps should be taken to get the blood sugar within a normal range to reduce the risk of heart defects in the developing fetus.