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Medical Screening and Special Testing Team from Women & Infants Publishes in Public Library of Science on Gestational Diabetes Findings

Release Date: 03/03/2016

James E. Haddow, MD, co-director of the Division of Medical Screening and Special Testing at Women & Infants Hospital, a Care New England hospital, and professor in the Department of Pathology and Laboratory Medicine at The Warren Alpert Medical School of Brown University; Geralyn M. Messerlian, PhD, director of the Division of Medical Screening and Special Testing and a professor in the Department of Pathology and Laboratory Medicine at the Alpert Medical School; Glenn E. Palomaki, PhD, associate director of the division and associate professor in the Department of Pathology and Laboratory Medicine at the Alpert Medical School, in collaboration with investigators in Dublin, New York, and Maine, have published their study “Free Thyroxine During Early Pregnancy and Risk for Gestational Diabetes” in the Public Library of Science (PLOS) ONE.

According to Dr. Haddow, their findings are the first to show that the well-known connection between obesity and gestational diabetes can be partially explained by altered thyroid hormone production. The thyroid gland itself functions normally among women with gestational diabetes. Altered thyroid hormone production takes place elsewhere in the body, where the inactive form of the hormone [thyroxine (T4)] is converted to the active form of the hormone [triiodothyronine (T3)].

Gestational diabetes mellitus (GDM) affects between three and 10 percent of pregnant women in the United States, depending on the nature of the population and how GDM is diagnosed. Women who are overweight or obese, older women, and some ethnic groups (particularly Asian women) are at particularly high risk.

The team identified obesity-induced deiodinase enzymes in the liver and muscles as the agent responsible for activating T3. Primary elements of this discovery emerged from analyses performed as an extension of a large observational study sponsored by the National Institutes of Health. Insights gathered from other published sources then supplemented the primary discovery. 
“Previously, nobody has connected the dots of triiodothyronine (T3) being a factor in gestational diabetes,” said Dr. Haddow. “The publication describes our finding that higher caloric intake leading to obesity, can trigger an increase in the active form of thyroid hormone, thereby contributing to gestational diabetes.”

“At present, accumulation of fat in the liver and muscles associated with over-nutrition is the best understood cause of insulin-resistance and type 2 diabetes,” said Dr. Haddow. “Our discovery identifies T3 as an additional causal agent, again driven by calories. While there is no immediate, obvious solution to modify the T3 hormonal balance associated with gestational diabetes other than weight reduction, our discovery is certainly a next step in allowing research questions to be designed aimed at improving management.”

For more information on the Women & Infants Division of Medical Screening and Special Testing visit

The world’s first multidisciplinary Open Access journal, PLOS ONE accepts scientifically rigorous research, regardless of novelty. PLOS ONE’s broad scope provides a platform to publish primary research, including interdisciplinary and replication studies as well as negative results. The journal’s publication criteria are based on high ethical standards and the rigor of the methodology and conclusions reported.


About Women & Infants Hospital 

Women & Infants Hospital of Rhode Island, a Care New England hospital, is one of the nation’s leading specialty hospitals for women and newborns. A major teaching affiliate of The Warren Alpert Medical School of Brown University for obstetrics, gynecology and newborn pediatrics, as well as a number of specialized programs in women’s medicine, Women & Infants is the 9th largest stand-alone obstetrical service in the country and the largest in New England with approximately 8,500 deliveries per year. A Designated Baby-Friendly® USA hospital, U.S.News & World Report 2014-15 Best Children’s Hospital in Neonatology and a 2014 Leapfrog Top Hospital, in 2009 Women & Infants opened what was at the time the country’s largest, single-family room neonatal intensive care unit.

Women & Infants and Brown offer fellowship programs in gynecologic oncology, maternal-fetal medicine, urogynecology and reconstructive pelvic surgery, neonatal-perinatal medicine, pediatric and perinatal pathology, gynecologic pathology and cytopathology, and reproductive endocrinology and infertility. It is home to the nation’s first mother-baby perinatal psychiatric partial hospital, as well as the nation’s only fellowship program in obstetric medicine.

Women & Infants has been designated as a Breast Imaging Center of Excellence by the American College of Radiography; a Center of Excellence in Minimally Invasive Gynecology; a Center of Biomedical Research Excellence by the National Institutes of Health (NIH); and a Neonatal Resource Services Center of Excellence. It is one of the largest and most prestigious research facilities in high risk and normal obstetrics, gynecology and newborn pediatrics in the nation, and is a member of the National Cancer Institute’s Gynecologic Oncology Group and the Pelvic Floor Disorders Network.