Children born to obese and overweight mothers are more likely to die early of heart disease, a study has found.
Scottish research showed a 35% higher risk of dying before the age of 55 in adults whose mothers were obese in pregnancy.
It is not known how much of the link is down to genetics, influences in the womb or later lifestyle.
But the authors say their findings, in the British Medical Journal, are of “major public health concern”.
One woman in five in the UK is obese at their antenatal booking appointment.
The analysis included 28,540 women whose weight was recorded at their first antenatal check-up and their 37,709 children now aged between 34 and 61.
One in five mothers was classed as overweight with a body mass index (BMI) between 25 and 29.9 and 4% were obese with a BMI above 30.
There were 6,551 premature deaths from any cause and heart disease was the leading contributor.
The risk of premature death was 35% higher among people born to obese mothers compared with those whose mothers had had normal weight in pregnancy. This was after adjusting the results for factors such as the mother’s age at delivery, social class and infant birthweight.
The results also revealed that children born to obese mothers went on to be at 42% increased risk of being treated in hospital for a heart attack, stroke or angina.
Study leader Prof Rebecca Reynolds, of the University of Edinburgh, said the results highlighted the importance of current advice to maintain a healthy weight, eat sensibly and keep active during pregnancy.
She added that more work was needed to unpick the reasons for the increased risk and to look at the impact of weight gain over pregnancy.
“It would be nice to know how much of this risk is modifiable.”
Previous research has shown a link between obesity in pregnancy and changes in appetite control and metabolism in children.
Prof Sir Stephen O’Rahilly, of the University of Cambridge, warned that obesity runs in families.
“Obese people are at higher risk of heart disease, so it is very likely that the people in this study whose mothers were obese were fatter than those whose mothers were lean.”
The researchers did not measure or account for this.
The Royal College of Midwives said it was important for women to start their pregnancy at a normal weight.
But Louise Silverton, RCM director for midwifery, said not all pregnancies are planned and midwives work hard to support women avoid excess weight gain and lose weight sensibly after birth.
Drastic dieting is not recommended.
Doireann Maddock, senior cardiac nurse at the British Heart Foundation, which part-funded the study, said: “This study emphasises the need for everyone, but in particular pregnant women, to try to eat healthily and be active.”