Pregnant women who are obese put their children at higher risk of developing asthma compared to mothers of normal weight, a large study in Sweden has found. The study, which covered over 129,000 mothers in Stockholm and their 189,000 children, found that mothers who were very obese, or with a body mass index of 35 and over, had a 61 percent increased risk of their children developing asthma by the time they were between 8 and 10 years of age.