Cancer Research UK has urged the Scottish Government to act after the “deeply concerning” statistics were revealed.
It urged a crackdown on supermarket multi-buy deals for junk food, arguing this would help everyone, including mothers-to-be, to cut back on foods with high levels of sugar, fat and salt.
Figures for 2017/18 showed 42 per cent of women who gave birth were classed as being a healthy weight, while 26.2 per cent were overweight and 22.7 per cent were obese.
Three-fifths (61 per cent) of pregnant women over the age of 40 were either overweight or obese compared to 36 per cent of those who were under 20.
“There has been a gradual increase in the proportion of overweight and obese women in all the age groups in the past five years,” the report noted.
Professor Linda Bauld, Cancer Research UK’s prevention expert based at the University of Edinburgh, said: “It’s deeply concerning that around half of women are overweight or obese in pregnancy.”
She spoke out after new NHS figures for 2017/18 showed 13,427 mothers-to-be were recorded as being overweight when they had their initial booking appointment for their pregnancy, with a further 11,604 classed as being obese.
Both of these totals were down on the previous year, when 50.7 per cent of mothers to be were in these groups.
Prof Bauld said: “Carrying too much weight causes around 2,200 cases of cancer every year in Scotland.
“New laws would work hard to turn around Scotland’s poor health record, but also do a great deal to ensure the future of new generations is in much better shape.” She said: “Tackling obesity is complex, but laws to restrict supermarket multi-buy offers on junk food would be an effective measure, helping everyone, including mums-to-be, from filling their shopping trolleys with foods high in fat and sugar.”
The figures also showed another rise in the number of women having surgical births, with 15.7 per cent of all babies delivered in 2017/18 born by planned Caesarean section.
A record number of 7,886 infants were born this way compared to 3,051 in 1975/76.
There was a slight fall in the number of babies delivered by emergency Caesarean section, falling from 8,710 in 2016/17 to 8,460 in 2017/18.
NHS data revealed of the 51,197 hospital births in Scotland in 2017/18, 14.4 per cent were to mothers who were smokers, down from 14.8 per cent the previous year and 28.7 per cent two decades ago.
More than half (54.2 per cent) of women giving birth were aged 30 or above.