New known fact: Children of obese women died earlier and had more heart problems later in life than those of normal weight mothers.
The offspring’s risk of death from any cause was 35% higher than individuals born to normal weight mothers. This was even AFTER adjustment for demographics, gestational (during pregnancy) and socioeconomic factors.
This study of 37,000 newborns born from 1950 to 1976 suggests that interventions for obese mothers should start BEFORE pregnancy. One of the researchers postulated that there are probably two reasons for this: both intrauterine metabolic programming (while still inside mother while the fetus is forming) and postnatal environment (exercise/diet patterns in the home after birth).
There are lots of health benefits, both physical and mental, for maintaining a healthy weight. Consider losing weight to be within a BMI of 20-25 before conception.
BMI calculator link. http://www.nhlbi.nih.gov/guidelines/obesity/BMI/bmicalc.htm
Hope this helps.