Updated 27 February 2017

Higher sugar levels in pregnancy bad for baby's heart

A new study suggests that even moderately elevated sugar levels during pregnancy may cause heart defects in unborn babies.

High blood sugar levels during pregnancy may increase a baby's risk of a heart defect, even among women without diabetes, a new study suggests.

"Diabetes is the tail end of a spectrum of metabolic abnormalities," said study lead author Dr James Priest, a postdoctoral scholar in paediatric cardiology at Stanford University in California. "We already knew that women with diabetes were at significantly increased risk for having children with congenital heart disease.

Blue baby syndrome

"What we now know... is that women who have elevated glucose or blood sugar values during pregnancy that don't meet our diagnostic criteria for diabetes also face an increased risk."

The researchers examined blood samples taken from 277 California women during the second trimester of pregnancy.

Read: Maternal obesity may influence brain development

The study participants included a control group of 180 women who had babies without heart defects. The other women had babies with one of two serious heart defects.

Fifty-five babies were born with structural problems in the heart and the blood vessels that connect the heart to the lungs, called tetralogy of Fallot. It is one of the heart defects that cause blue baby syndrome, in which a baby gets too little oxygen, the researchers said.

The other 42 babies were born with dextrotransposition of the great arteries, in which the two main arteries leading from the heart are switched in position. This prevents oxygenated blood from the lungs from circulating to the body, the researchers explained.

New avenues for research

The researchers' analysis linked elevated blood sugar levels even if below the cutoff for diabetes with an increased risk of tetralogy of Fallot, but not with dextrotransposition of the great arteries.

Read: 6 diabetes myths debunked

Also, the researchers found no significant association between levels of insulin the hormone that regulates blood sugar and either type of heart defect.

"I'm excited by this research," Priest said in a university news release. "Most of the time we don't have any idea what causes a baby's heart defect."

Several other kinds of structural birth defects, in addition to heart defects, have been linked with diabetes, he added.

The new findings could lead to new avenues for research, added study senior author Gary Shaw.

"This new work will motivate us to ask if underlying associations with moderately increased glucose levels may be similarly implicated in risks of some of these other birth defects," Shaw, a professor of paediatrics in neonatal and developmental medicine, said in the news release.

Read more:

Drinking at conception ups baby's diabetes risk  

Mom's diabetes control in pregnancy may affect kids' brains

Diet tips for pregnant moms

Image: Baby with a heart monitor from iStock


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Ask the Expert

Diabetes expert

Dr. May currently works as a fulltime endocrinologist and has been in private practice since 2004. He has a variety of interests, predominantly obesity and diabetes, but also sees patients with osteoporosis, thyroid disorders, men's health disorders, pituitary and adrenal disorders, polycystic ovaries, and disorders of growth. He is a leading member of several obesity and diabetes societies and runs a trial centre for new drugs.

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules