London - One woman in three experiences "out of control" eating while pregnant, a study has found.
While expectant mothers often joke about "eating for two", it can have serious implications for their health and that of their children, researchers said.
One in 20 pregnant women surveyed gained half a stone (about 3kg) more than those who did not lose control over eating.
The children of these women had double the chance of becoming obese by the age of 15, the researchers discovered.
The study of more than 11 000 women, published in the American Journal of Clinical Nutrition, found 36.3 percent experienced loss of control eating in pregnancy.
Researcher Dr Nadia Micali, of UCL Great Ormond Street Institute of Child Health, said: "This is the first study to investigate loss of control eating during pregnancy and its effects on pregnancy, child birth-weight and long-term weight.
"We found loss of control eating is common and despite having serious implications for mothers and children, it has received very little attention. Gestational weight gain not only puts children at a greater risk of being obese but is a predictor of later obesity in mothers."
She added: "Our findings further the understanding of risk factors for obesity and highlight an urgent need for better identification and support for mothers who experience loss of control eating."
The study was based on an analysis of data from 11 132 women in the Avon Longitudinal Study of Parents and Children, also known as Children of the 90s.
It found that 582 women reported frequent loss of control eating and 3 466 experienced it occasionally.
Women completed a food frequency questionnaire at 32 weeks pregnant and their weight gain and babies’ birth-weight were obtained from obstetric records.
To determine any effect on the next generation, the weight and height of 5 515 children were measured at 15 years. Those whose mothers experienced out of control eating were more likely to be obese.
Women who experienced loss of control eating were also more likely to diet while pregnant and were more dissatisfied with their body shape.
At the same time, they consumed more snacks such as chocolate and cakes, ate more calories overall and had lower intakes of vitamins A, C and B6.