Early blood testing could identify women at risk of gestational diabetes

Early blood testing could identify women at risk of gestational diabetes
Early blood testing could identify women at risk of gestational diabetes Photo: Shutterstock

Early blood testing could identify women at risk of developing gestational diabetes later in the pregnancy, according to the findings of a recent study.

Instead of waiting until between 24 and 28 weeks of pregnancy to take a Glucose Tolerance Test (GTT), researchers claim women could be tested much earlier to see if they are at risk of developing the condition. Pregnant women could then better protect themselves against developing gestational diabetes by making lifestyle changes earlier in the pregnancy. 

Gestational diabetes is a pregnancy-related condition, where the level of blood sugar, or glucose, rises too high. It has potentially serious health risks for mothers and infants. Risks include high blood pressure, the need for cesarean delivery and large birth sizes. 

Researchers at the National Institute of Child Health and Human Development (NICHD) discovered a blood test conducted as early as the 10th week of pregnancy could help identify pregnant women at risk of developing gestational diabetes.

In the study, researchers evaluated whether the test used to commonly diagnose type 2 diabetes - HbA1c test - could be used to identify signs of gestational diabetes in the first trimester of pregnancy. 

They examined records from the NICHD Fetal Growth Study, a study of more than 2,000 low-risk pregnant women in the United States during 2009 and 2013. The researchers compared HbA1c test results from 214 women who did not develop gestational diabetes to those of 107 women who did. 

It was found that the women who went on to develop gestational diabetes had higher HbA1c levels, compared to those without it.

"Our results suggest that the HbA1C test potentially could help identify women at risk for gestational diabetes early in pregnancy, when lifestyle changes may be more effective in reducing their risk," said the study's senior author, Dr Cuilin Zhang.

Lifestyle changes that may help lower blood glucose levels during pregnancy include exercise and a healthy diet. However, when these measures are not successful, insulin is used to bring blood glucose under control.

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Fellow of the Royal Australian and New Zealand Council of Obstetricians and Gynaecologists (RANZCOG) Dr Philippa Costley said the results of the study were interesting in that there seemed to be an apparent association in HbA1c early in pregnancy and the development of gestational diabetes. 

"The range is very small which could make it difficult to implement into clinical practice as the cut-off used to distinguish between high and low risk may be difficult to determine," Dr Costley said.

"It is also difficult to know whether labelling a woman as high-risk and implementing lifestyle changes early in the pregnancy would have any impact on the outcome of her pregnancy."

Dr Costley said more research was needed to determine if the early blood test would be a useful screening tool.

"It would then need to be examined whether or not early lifestyle modifications would impact on the pregnancy," she said.

Gestational diabetes affects 10 to 15 per cent of the population and is most prevalent among women aged over 40-years-old, those with a family history of diabetes or polycystic ovarian syndrome, or who had previously had large babies or were overweight. Asian, Indian subcontinent, Aboriginal, Torres Strait Islander, Pacific Islander, Maori, Middle Eastern and non-white African women are also at risk.

"Women should ensure they are maintaining a healthy diet and exercising regularly," she said. "This will help maintain a healthy body weight and can help prevent gestational diabetes.

"However, some women have a genetic predisposition, and despite these measures, may still develop gestational diabetes and may require medication to maintain their blood glucose levels."