Maternal insulin resistance linked to higher abdominal fat in girls

Girls born to mothers with higher insulin resistance during the third trimester are more likely to have more abdominal fat at age 7, according to research presented at the 28th European Congress of Endocrinology in Prague. Maternal insulin resistance was not associated with body fat in boys, suggesting that girls may be more susceptible to the mother's insulin resistance during late pregnancy. The findings highlight the importance of maternal metabolic health for the future wellbeing and health of children.

During pregnancy, the body needs much more insulin after the first trimester due to hormonal changes in the placenta. Insulin resistance peaks in the third trimester of pregnancy – typically around weeks 32-36. Early life exposure to different hormones can shape long-term health in children.

In this study, researchers from the Odense University Hospital in Denmark analysed data on insulin resistance, fasting blood sugar and insulin levels of 903 women during their third trimester of pregnancy, from the Odense Child Cohort. They also measured the body composition of 903 children aged 7 years and found that girls exposed to higher insulin resistance in the womb had more fat around the central trunk and upper body, around the lower body, and more total body fat. In addition, every 1 mmol/L higher maternal fasting blood sugar level was associated with about a 6% higher body fat percentage in girls. These findings held irrespective of the mother's pre-pregnancy weight.

Though previous studies have shown an association between maternal blood sugar levels and children's body fat mass, there are inconsistent results on the differences between boys and girls. "Our findings indicate that girls may be more susceptible than boys to the effects of maternal insulin resistance during pregnancy. In boys, more body fat was primarily explained by the mother's BMI, whereas in girls, the specific metabolic environment in the womb – independent of the mother's weight – seems to play a larger role," said Dr Camilla Viola Palm, who was involved in the study.

Our study contributes new insight by using measures of insulin resistance in the third trimester and DXA scans to assess fat distribution in 7-year-old children. In addition, the participating mothers and health professionals had no knowledge of the glucose and insulin assessments, which ensured that the results were not influenced by any changes in diet or medical treatment".

Dr. Camilla Viola Palm

"The pregnant women in our study were relatively lean and healthy, suggesting that even in mothers without metabolic risk, higher insulin resistance during pregnancy may programme future abdominal fat deposition in their girls," said Dr Palm. "Extra abdominal fat may increase the girls' risk of developing type 2 diabetes and cardiovascular disease later in life, thus maternal insulin resistance should ideally be addressed early in pregnancy − or ideally prior to conception."