"The phenomenon has forced maternity wards to purchase stronger operating room tables, extra-wide chairs, heavier scales and other specialized equipment to cope with the growing proportion of dangerously obese pregnant women arriving on labour and delivery wards."

That's the concluding paragraph of a news report with the attention-grabbing headline of Study finds obesity during pregnancy bad for baby's heart. Apart from the very glaring obviousness that extreme weight gain poses a health threat for anyone whose BMI exceeds 30, with abdominal fat in particular causing huge problems for human viscera, there is the issue of difficulties during childbirth among obese women.

A nurse attends to a premature newborn in the neo-natal ward of the Delafontaine hospital in Saint Denis near Paris on March 19, 2013. A mother’s obesity during pregnancy appears to set her baby up for an increased risk of heart attack and stroke when he or she is older, Canadian researchers are reporting.  Photograph by: JOEL SAGET , AFP/Getty Images

And since it is estimated by figures available through Statistics Canada that 23% of women in Canada of child-bearing age are obese, this is a startling and growing problem. It is not that unusual, according to obstetricians reporting on their own experiences, to come across expectant mothers with a BMI of 50. That's not merely overweight, heavy, fat and even obese, it's over-obese to the point of morbidity.

New Canadian-sourced data, as published in the Proceedings of the National Academy of Sciences, points to obese expectant mothers giving birth to children whose genes are deleteriously affected by the fact of the mother's obesity, to make them susceptible for increased risk of heart attack and stroke when the offspring mature.

That's not a useful legacy for a mother to leave to her children. No mother would deliberately seek to do such a thing. But it makes sense when someone plans parenthood for their future to look to the state of their health before embarking on that course. Not only for their own state of health, but that of their planned children.

The study undertaken by Laval University researchers in Quebec City sought as recruits twenty women who had undergone stomach-shrinking surgery. They examined the genes of children born to these women before that surgery had taken place as well as the genes of offspring born afterward. Obesity, according to the study's conclusions, somehow alters the womb environment and by extension, a baby's DNA.

Higher rates of serious complications for women and their babies are surfacing as new generations of pregnant women with extreme obesity are increasingly giving birth. 'Fetal programming' appears to be a pattern in these high-risk births with a critical process called methylation, where molecules grip on DNA, acting to turn genes up or down.

"We wanted to know what was going on at the molecular level", explained study co-author Marie-Claude Vohl, of Laval's Institute of Nutrition and Functional Foods.

Weight-loss surgery called biliopancreatic bypass, to make for a reduced abdomen for with women presenting with an average body mass index of 45, was shown to affect babies born after that surgery, endowing them with different genes than their siblings born before that surgery took place.

Children born before surgery had compromised 'metabolic' health; increased risk factors for heart disease and diabetes. "If they develop a healthier lifestyle, it may compensate for this susceptibility. It may help protect them against the development of several chronic diseases", Dr. Vohl stated placatingly.

However, she added, "What we can see here is the impact of obesity not only on the mother, but the impact of obesity on the next generation."