If you are pregnant, it is normal to gain weight; however, carrying too many extra pounds before and during pregnancy is unhealthy not just for you, but your unborn child.
According to a report in the Journal of Allergy and Clinical Immunology, babies of obese mothers (i.e., mothers having a pre-pregnancy body-mass index [BMI] of 30 or more) were 41 percent more likely to develop asthma. Even babies of overweight women (i.e., mothers having a pre-pregnancy BMI of 25.0-29.9) were 18 percent more likely to get asthma. The study also indicated babies born to obese mothers were more likely to be obese themselves.
Since dieting during pregnancy is discouraged, the best advice for obese and overweight women is to start a weight-loss program before starting a family.