Pregnant woman and Moderna vaccine
Women who received metformin also exhibited lower weight gain throughout the trial, maintaining this difference even at the 12-week post-delivery visit. Photo: Pixabay

Gestational diabetes mellitus (GDM) has long posed a significant health risk to expectant mothers and their babies, affecting nearly three million pregnant women worldwide each year.

However, a groundbreaking clinical trial conducted by researchers at the University of Galway is providing new hope for the management of this condition.

The findings from this trial, known as EMERGE (Effective Management of Gestational Diabetes with Metformin: a Randomised Controlled Trial), have been published in the prestigious Journal of the American Medical Association (JAMA).

Gestational diabetes is a condition characterised by elevated blood sugar levels during pregnancy, which can lead to various health complications for both mothers and infants.

Professor Fidelma Dunne, a renowned expert in the field of endocrinology and a professor at the University of Galway, spearheaded the EMERGE trial, which involved more than 500 pregnant women. The trial's results have the potential to revolutionise the way GDM is managed and treated.

The key findings from the EMERGE trial are remarkable. Pregnant women treated with metformin were not only 25 per cent less likely to require insulin therapy, but when insulin was necessary, it was typically initiated later in pregnancy.

Metformin, a medication with a long history of use in Type 2 diabetes management spanning over 60 years, demonstrated its effectiveness in addressing gestational diabetes.

Furthermore, the study highlighted improved blood sugar control among women receiving metformin, as evidenced by significantly lower fasting and post-meal sugar values at weeks 32 and 38 of pregnancy. These results signify a potential shift in the way gestational diabetes is managed, emphasising the benefits of metformin treatment.

In addition to improved sugar control, metformin-treated women also managed their weight more effectively throughout the trial. This difference in weight gain was sustained even at the 12-week post-delivery follow-up, offering a holistic approach to better maternal health during and after pregnancy.

Importantly, the EMERGE trial dispelled concerns about metformin's impact on gestational age, as it found that delivery occurred at the same mean gestational age (39.1 weeks) in both groups. There was no evidence of an increase in preterm births (birth before 37 weeks) among those who received metformin, further reinforcing its safety and efficacy.

The benefits extended to newborns as well, with infants born to mothers who received metformin having an average birth weight of 113 grams less than those in the control group.

Moreover, significantly fewer infants in the metformin group were classified as large at birth, weighing over 4 kilogrammes (8 pounds 8 ounces). This finding suggests a potential reduction in the risks associated with high birth weight, which can have various health implications for newborns.

Remarkably, the study revealed no differences in adverse neonatal outcomes between the two groups. There were no variations in the need for intensive care treatment for newborns, respiratory support, jaundice, congenital anomalies, birth injuries or low sugar levels. These results provide reassurance regarding the safety of metformin in the context of gestational diabetes management.

Additionally, the trial assessed maternal outcomes and found no variations in rates of labour induction, caesarean delivery, maternal haemorrhage, infection, or blood pressure issues during or after birth. These findings suggest that metformin treatment does not introduce any additional maternal health risks compared to standard management approaches for gestational diabetes.

These remarkable findings were presented by Professor Fidelma Dunne at the 59th Annual Meeting of the European Association for the Study of Diabetes in Hamburg, Germany, on October 3, 2023.

Professor Dunne emphasised the significance of the EMERGE study, stating: "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."

She further 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."

The EMERGE trial involved 535 pregnant women, with 268 receiving metformin and 267 receiving a placebo. Remarkably, 98 per cent of women remained in the trial until delivery, and 88 per cent completed the 12-week post-delivery follow-up assessment. Moreover, only 4.9 per cent of women discontinued medication due to side effects, highlighting the safety of the interventions.

Traditionally, gestational diabetes has been managed initially through dietary advice and exercise, with insulin introduced if sugar levels remain suboptimal. However, insulin use can pose challenges, including low sugars in both the mother and infant, excessive weight gain for mothers, and higher caesarean birth rates. Mothers with gestational diabetes are also at greater risk of high blood pressure and preeclampsia.

Babies born to mothers with gestational diabetes face their own set of risks, such as excessive birth weight, birth injuries, respiratory difficulties, and low sugar levels after delivery, potentially requiring admission to neonatal intensive care. Gestational diabetes also increases the lifetime risk of diabetes for both mothers and their children, as well as elevating mothers' lifetime risk of cardiovascular disease.

The implications of the EMERGE study extend beyond high-income countries, as low and middle-income countries bear a significant burden of gestational diabetes cases. The availability of a safe and effective treatment like metformin can potentially benefit women and infants worldwide.