New Hope for Safe and Effective Gestational Diabetes Treatment

Gestational diabetes is a global health issue affecting almost 3 million pregnant women worldwide every year. It is a condition characterized by elevated blood sugar levels during pregnancy, posing increased health risks for both mothers and their babies.

Professor Fidelma Dunne, Professor of Medicine at University of Galway and Consultant Endocrinologist at Saolta University Health Care Group, managed the EMERGE, randomized, placebo-controlled trial, involving more than 500 pregnant women.

It found:

  • Women assigned to metformin were 25% less likely to need insulin, and when insulin was necessary, it was started later in the pregnancy. Metformin is used routinely in the treatment of Type 2 Diabetes and has been widely available for over 60 years.
  • Fasting and post-meal sugar values in the mother were significantly lower in the metformin exposed group at weeks 32 and 38.
  • Women receiving metformin gained less weight throughout the trial and maintained this weight difference at the 12-week post-delivery visit.
  • Importantly, delivery occurred at the same mean gestational age (39.1 weeks) in both groups. There was no evidence of any increase in preterm birth (defined as birth before 37 weeks) among those who received metformin.
  • Infants born to mothers who received metformin weighed, on average, 113g less at birth, with significantly fewer infants classified as large at birth, or weighing over 4kg (8lbs 8ounces).
  • While there was a slight reduction in infant length (0.7cm), there were no other significant differences in baby measurements.
  • There were slightly more babies who were small at birth but this did not reach statistical significance.

Professor Dunne said: “While there is convincing evidence that improved sugar control is associated with improved pregnancy outcomes, there was uncertainty about the optimal management approach following a diagnosis of gestational diabetes.

“In our pursuit of a safe and effective treatment option we explored an alternative approach — administering the drug metformin. A previous trial compared metformin to insulin and found it to be effective, yet concerns remained, especially regarding preterm birth and infant size.”

Professor Dunne said: “Traditionally, gestational diabetes has been managed initially through dietary advice and exercise, with insulin introduced if sugar levels remain suboptimal. While effective in reducing poor pregnancy outcomes, insulin use is associated with challenges, including low sugars in both the mother and infant which may require neonatal intensive care, excess weight gain for mothers, and higher cesarean birth rates.

Professor Dunne added: “The results from the EMERGE study are a significant step forward for women with gestational diabetes. Metformin has emerged as an effective alternative for managing gestational diabetes, offering new hope for expectant mothers and healthcare providers worldwide.”


Fidelma Dunne, Christine Newman, Alberto Alvarez-Iglesias, John Ferguson, Andrew Smyth, Marie Browne, Paula O’Shea, Declan Devane, Paddy Gillespie, Delia Bogdanet, Oratile Kgosidialwa, Aoife Egan, Yvonne Finn, Geraldine Gaffney, Aftab Khattak, Derek O’Keeffe, Aaron Liew, Martin O’Donnell. Early Metformin in Gestational Diabetes. JAMA, 2023; DOI: 10.1001/jama.2023.19869

University of Galway. “Pregnant women offered new hope for safe and effective gestational diabetes treatment.” ScienceDaily. ScienceDaily, 3 October 2023. < >.

Materials provided by University of Galway. Note: Content may be edited for style and length.

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Photo by Juan Encalada