High Blood Sugar During Pregnancy Ups Risk of Mother’s Type 2 Diabetes, Child’s Obesity

Research conducted in part at Ann & Robert H. Lurie Children’s Hospital of Chicago found that mothers with elevated blood glucose during pregnancy – even if not high enough to meet the traditional definition of gestational diabetes – were significantly more likely to have developed type 2 diabetes a decade after pregnancy than their counterparts without high blood glucose.

For children born to mothers with elevated or normal glucose, researchers found no statistically significant difference between the two groups of children in terms of their combined overweight and obesity, the study’s primary outcome. However, when obesity was measured alone, children of mothers with elevated blood glucose were significantly more likely to be obese.

The results are part of a follow-up study published Sept. 11 in the Journal of the American Medical Association (JAMA). Funded primarily by the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), part of the National Institute of Health, and conducted at 10 study sites, including Lurie Children’s, the Hyperglycemia and Adverse Pregnancy Outcomes-Follow-up Study or HAPO-FUS, followed mothers and their children 10-14 years after birth.

“Our results demonstrate that even women with mild hyperglycemia during pregnancy and their offspring are at risk of harmful maternal and child health outcomes, potentially increasing the number of women and children at risk of acquiring lifelong chronic medical conditions,” says study Principal Investigator and co-author Wendy Brickman, MD, pediatric endocrinologist at Lurie Children’s and Associate Professor of Pediatrics at Northwestern University Feinberg School of Medicine. 

The original HAPO study found that even modestly elevated blood glucose levels increased the risks of complications for the baby both before and shortly after birth. Based on these results many, but not all, organizations adopted a new definition of gestational diabetes, a type of diabetes that occurs during pregnancy.

HAPO-FUS compared the long-term effects of blood glucose levels in mothers who would have met the new definition of gestational diabetes with those who did not. Researchers aimed to learn if modest increases in blood glucose increased the mother’s risk of developing type 2 diabetes or prediabetes and the risk of obesity in the mother’s offspring at least a decade after giving birth.

The study found the harms of even modestly elevated blood glucose for both mother and child extend more than a decade. Among women with elevated blood glucose during pregnancy, nearly 11 percent had type 2 diabetes at the follow-up study visit 10-14 years after childbirth and about 42 percent had prediabetes. Of their counterparts who did not have elevated blood glucose during pregnancy, about 2 percent had type 2 diabetes and about 18 percent had prediabetes. The study examined 4,697 mothers for type 2 diabetes, prediabetes and other disorders of glucose metabolism.

Researchers analyzed 4,832 children for overweight and obesity, collecting data using body mass index (BMI), body fat percentage, skin fold thickness and waist circumference. They found that these measures all showed that children born to mothers with elevated glucose levels were more likely to be obese. For example, using BMI, 19 percent of children born to mothers with elevated blood glucose were obese, compared with 10 percent for children of mothers with normal glucose.  

Adjusting for the mother’s BMI reduced – but did not eliminate – the differences between the groups.

“Future research will provide an opportunity to learn how to prevent these poor outcomes, potentially intervening before the child is born or even before pregnancy has started,” says Dr. Brickman.

The original HAPO study looked at 23,316 mother-child pairs and found that a mother’s blood sugar levels, even short of diabetes, were associated with her newborn’s birth weight and body fat. HAPO results led an international panel of experts to recommend new diagnostic criteria for gestational diabetes in 2010. However, not all professional groups adopted these proposed criteria.

None of the women in HAPO-FUS were diagnosed with or treated for gestational diabetes during their pregnancy. HAPO recruited an international, racially and ethnically diverse group. Limitations of the data in HAPO include that body mass index was obtained during pregnancy, not before. As well, HAPO-FUS did not collect data on the women or children’s lifestyles to evaluate other factors that could contribute to obesity or type 2 diabetes.

The results build on findings from other studies showing that type 2 diabetes in mothers during pregnancy is associated with obesity in that mother’s offspring and that elevated blood glucose increases risk of type 2 diabetes in the woman after pregnancy.

HAPO-FUS was conducted at 10 clinical centers around the world:

• Northwestern University and Ann & Robert H. Lurie Children’s Hospital of Chicago, Chicago
• Kaiser-Permanente Southern California Department of Research and Evaluation, Pasadena, California
• Case Western Reserve University at Metro Health Medical Center, Cleveland
• The Hospital for Sick Children, Toronto
• Rajavithi Hospital, Bangkok
• The University of the West Indies, Bridgetown, Barbados
• Royal Victoria Hospital, Belfast, Northern Ireland
• The Chinese University of Hong Kong
• Royal Manchester Children’s Hospital, Manchester, England
• Helen Schneider Hospital for Women, Petah Tikva, Israel

HAPO-FUS was funded under NIDDK grant 1U01DK094830, and NIH’s National Center for Advancing Translational Sciences grant UL1TR001422, with additional support from NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development.

Learn more about HAPO-FUS at www.hapo.northwestern.edu/index.html.

Research at Ann & Robert H. Lurie Children’s Hospital of Chicago is conducted through the Stanley Manne Children’s Research Institute. The Manne Research Institute is focused on improving child health, transforming pediatric medicine and ensuring healthier futures through the relentless pursuit of knowledge. Lurie Children’s is ranked as one of the nation’s top children’s hospitals in the U.S.News & World Report. It is the pediatric training ground for Northwestern University Feinberg School of Medicine. Last year, the hospital served more than 208,000 children from 50 states and 58 countries.