The research into the causes of bulimia, anorexia and related symptoms shows that there are significant links with a number of disruptive childhood experiences, but sexual abuse is the main factor.
The report, from the Children of the 90s project at the University of Bristol, is published in the British Journal of Psychiatry.
Of almost 10,000 women, 18 per cent said they had experienced unwanted sexual contact before the age of 16. Those women were twice as likely to show symptoms of an eating disorder.
The lead authors Dr Rob Senior from the Leopold Muller Centre for Child and Family Mental Health, University College London and Professor Jacqueline Barnes, Birkbeck, University of London say that among women of childbearing age, the signs of anorexia or bulimia nervosa are common.
Up to 4 per cent show symptoms such as extreme concern about body shape and weight, and disrupted eating patterns, with self-induced vomiting and use of laxatives to lose weight.
The report says: "Pregnancy itself has an inevitable impact on attitudes to weight and shape and on eating disorder symptoms. There is evidence from a number of studies that pregnant women are generally accepting of their larger body size and make few attempts to control it.
"However, in samples of women with eating disorders, many expressed negative feelings about the weight gain and changes in body shape during pregnancy."
Previous research has shown that eating disorders may be connected to a wide range of unhappy childhood influences including parents alcohol misuse, physical or emotional cruelty, and other family disruption.
In this study 79 per cent of the women recalled a happy childhood. They were less likely to worry about their shape or weight, or to show other symptoms of eating disorder.
Of those who reported sexual abuse, 15 per cent showed symptoms of an eating disorder, and 30 per cent showed marked concern about their shape during pregnancy.
The report concludes: "There are substantial public health implications. Eating disorders in mothers in the period immediately after childbirth pose a particular risk to the developing child by interfering with parenting and child growth.
"It has already been shown that women with excessive concerns about shape and weight are less likely to plan breast-feeding.
"Health professionals dealing with pregnant women need to be aware of the high prevalence of eating disorder symptoms and the possible association in some women with a history of adverse experiences in childhood.
"The majority of women with concerns about weight, shape and eating do not describe a history of abuse and GPs or midwives may have reservations about raising the topic, but it may be important to enquire during pregnancy about a history of eating problems and to provide the opportunity for early experiences to be discussed."
'Early experiences and their relationship to maternal eating disorder symptoms, both lifetime and during pregnancy' R.Senior, J.Barnes, J.R.Emberson and J.Golding on behalf of the ALSPAC Study Team The British Journal of Psychiatry