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03 January 2023

BMI less useful than other measures of adiposity when assessing risk of developing gestational diabetes amongst women with obesity

Weight gain and adiposity change during pregnancy were less important in determining risk, reinforcing the idea that women with obesity should concentrate on becoming as fit as they can before pregnancy.

Gestational diabetes insulin

Several well-known factors have been shown to contribute to the development of gestational diabetes (GDM) in the general pregnant population, and women with a raised Body Mass Index (BMI) are considered to be at higher risk.

To better understand which women with obesity might develop GDM, researchers in the School of Life Course & Population Sciences set out to discover whether the factors that might predispose pregnant women with obesity to GDM were similar or different to those recognised in the general population.

The researchers, led by Dr Sara White in the Department of Women & Children’s Health, found that some factors were as important in women with obesity; increasing age was significant, and previous GDM – whether the individual was obese or not – was associated with an increased likelihood of having GDM again.

They also found that specific markers of size/adiposity measured in early pregnancy, such as neck circumference and subscapular (under shoulder blade) skinfold thickness, were more useful than weight alone in this group. Notably, the researchers found that in this obese group the change of weight or measures of weight across pregnancy was less important than at the beginning of pregnancy, reinforcing the idea that the best time to improve weight to reduce GDM risk is before conception.

The findings of the study have expanded knowledge around measures that are associated with the development of GDM specifically amongst pregnant women with obesity, rather than assuming that the whole group is at risk. Equally, it has shown that the change in weight/adiposity measures across pregnancy are less important in determining risk of GDM than these same measures when a woman becomes pregnant, emphasising the need for improving weight and fitness before conception.

This work has expanded knowledge on the risk factors for gestational diabetes that are specific to women with obesity; some, such as age and a previous experience of gestational diabetes are equally important as for normal weight women, but specific patterns of weight/adipose distribution in early pregnancy are more discriminatory for women with obesity than weight alone amongst an obese group.”

Dr Sara White

The researchers are now working towards a targeted intervention to try to improve outcomes in this group through an understanding of which specific group of women with obesity are at higher risk of developing GDM.

Read the full paper Gestational diabetes in women with obesity; an analysis of clinical history and simple clinical/anthropometric measures in PLOS One.