If the pregnant woman is overweight rather than obese, the increased risk of type 2 diabetes in the child is 40%, said the researchers from the University of Edinburgh.
“Pregnancy represents a potential time to intervene with health advice for the family”
As a result, they called for strategies to be introduced urgently to reduce obesity and overweight in women of reproductive age, noting that pregnancy represented a ”potential time to intervene with health advice for the family”.
Their study is published in Diabetologia, the journal of the European Association for the Study of Diabetes.
They noted that the short-term complications of maternal obesity were well recognised, including gestational diabetes, pre-eclampsia, larger infants and a higher likelihood of caesarian delivery.
In addition, they warned there was now an increasing awareness that there were longer term cardiovascular health problems for infants born to obese mothers.
The study, led by Professor Rebecca Reynolds, examined the link between maternal body mass index and the risk of the offspring developing a clinically confirmed diagnosis of diabetes up to adulthood.
The study linked birth records of 118,201 children from 1950 to 2011 in the Aberdeen Maternity and Neonatal Databank with data from the national register for diagnosed diabetes in Scotland.
The data showed that 25% of the pregnant women were overweight and 10% were obese across all years studied.
Compared with normal weight mothers, being overweight or obese during pregnancy was associated with a significantly increased risk of any diabetes in the child, with an increased risk of 26% for overweight mothers and 83% for obese mothers.
However, when looking only at type 2, the increased risks were even higher. Being an obese mother was associated with a 3.5 times increased risk in the child, while it was 40% for overweight mothers.
The underlying mechanism for the association is unknown, noted the researchers. One theory is that obesity in the mother produces an “adverse in-utero environment”.
“Our findings have profound public health implications”
The study authors said: “This large cohort study, using over 60 years of pregnancy data linked to the national diabetes dataset in Scotland, showed a significant association between maternal BMI and incidence of diabetes in the offspring.
“This association may partly explain the link between being overweight or obese during pregnancy and offspring cardiovascular disease and mortality rates – highlighting a potential target for intervention,” they said.
They added: “With the rising prevalence of being overweight/obese in women of childbearing age our findings have profound public health implications.”
“There is an urgent need to establish effective approaches to prevention of obesity and diabetes among mothers and their offspring. Pregnancy represents a potential time to intervene with health advice for the family,” they said.
Data from Health Survey for England 2017 suggests around half of all women of childbearing age are overweight or obese. Looking only at women aged 25-44 years, this proportion rises to almost 60%.