Study: Pregnant Women With Type 1 Diabetes at Risk of Giving Birth Prematurely

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By : dLife Editors

Pregnant women with Type 1 diabetes are at increased risk of delivering their baby prematurely, according to new research from Sweden.

In a previous study published in The BMJ, the research group from Karolinska Institutet and the Sahlgrenska Academy in Sweden showed that pregnant women with Type 1 diabetes were at an increased risk of having babies with heart defects.

Now, a new study is published that shows how women with Type 1 diabetes have an increased risk of giving birth prematurely.

“High long-term blood sugar, so-called HbA1c, during pregnancy is linked to an increased risk for complications, including preterm birth,” explains Jonas F. Ludvigsson, professor at the department of medical epidemiology and biostatistics at Karolinska Institutet and Senior Physician at the Department of Paediatrics at Örebro University Hospital.

“The risk is highest amongst those with HbA1c levels above 8-9 percent, but even those who maintain their HbA1c below 6.5 percent are at an increased risk of giving birth prematurely,” he says.

How was the Study Conducted?

The study involved linking the Swedish Medical Birth Register (MFR) to the Swedish National Diabetes Register (NDR) for the years 2003 to 2014.

Researchers identified 2,474 infants born to women who recorded long-term glycosylated hemoglobin levels (HbA1c) during pregnancy. These were compared to 1.16 million infants born to women without diabetes.

Approximately 22 percent of infants born to women with Type 1 diabetes were born prematurely, which can be compared to below five percent of infants born to women without Type 1 diabetes.

37 percent of women with Type 1 diabetes and an HbA1c level above 9 percent gave birth prematurely. Yet even 13 percent of those with adhering to the current recommendations for blood sugar gave birth too early.

“This is the first study large enough to demonstrate a clear relationship between different HbA1c levels and preterm birth,” says Ludvigsson. “Our study has been conducted nationally and thus provides a result that can be applied to the average woman with Type 1 diabetes.”

The study also found an increased risk of these newborns being “large for gestational age,” being injured during childbirth, experiencing respiratory problems, low blood sugar and suffering from lack of oxygen in addition to higher neonatal mortality rates amongst those exposed to high blood sugar during pregnancy.

Also, the risk of stillbirth was linked to HbA1c levels in pregnant women with Type 1 diabetes.

The next step for researchers is to examine the long-term outcome of these children.

The study was conducted with support from the Swedish Diabetes Fund.

Research published in Annals of Internal Medicine.

Karolinska Institutet.


  1. Karolinska Institutet. Pregnant women with type 1 diabetes are at risk of giving birth prematurely. EurekAlert! Retrieved: