Growing rates of overweight and obese women is triggering a new generation of overweight children. Women over the age of 25, and especially those over 35, have the highest risk of gestational diabetes. It can be genetic but experts agree that one’s lifestyle is the most important predictor. Up to 60 per cent of women who have gestational diabetes will develop type 2 diabetes within 5 years of their pregnancy.If you’re overweight or obese, your chances of having gestational diabetes is two and four times higher, respectively, than women of normal weight, according to a report in the journal Diabetes Care. If you use tobacco, your chances double.Gestational diabetes is a type of diabetes that affects women during pregnancy, causes babies to be large for their gestational age, and sets mothers and children up to suffer type 2 diabetes and related conditions later in life. Most women who have gestational diabetes can deliver healthy babies but it increases the likelihood of needing delivery by C-section. Excess blood glucose that is seen in diabetes crosses the placenta, triggers insulin and promotes fat storage. Larger babies get wedged in the birth canal and can suffer severe birth complications. Gestational diabetes can also cause early or preterm birth and respiratory distress syndrome – both major contributors to high infant mortality rates. Babies of mothers with gestational diabetes are more likely to experience respiratory distress syndrome even if they’re not born early.After birth, when insulin starts to kick in and the baby’s blood sugar drops, the infant is at risk for seizures, jaundice, polycythaemia vera, low calcium and low magnesium, according to Dr Timothy Morley, medical director for Women’s Healthy Hormones. Immediate breastfeeding can often normalize a baby’s blood sugar level.Gestational diabetes can cause high blood pressure, preeclampsia and eclampsia in otherwise healthy mothers. Preeclampsia is the most common complication during pregnancy and is characterized by a sudden, sharp rise in blood pressure.Preeclampsia affects about 1 in every 20 pregnancies but obesity trends are causing it to become even more common."More people are going into pregnancy overweight,” said Dr Danine Fruge, director of women’s health and family medicine at the Pritikin Longevity Centre and Spa.Many women who aren’t diabetic going into pregnancy may still have metabolic syndrome and insulin resistance – risk factors they may not have had if they had a normal body mass index (BMI), Fruge said.Type 2 diabetes is a major risk factor in the development of heart attack and stroke. Women who had gestational diabetes have a 26 per cent higher 10 year-risk for heart disease, according to a recent study in the journal Circulation.In a similar study published in the journal Diabetes Care, women who have had gestational diabetes have a higher risk of blood vessel disease, cholesterol problems, clogged blood vessels, and metabolic syndrome.Exercise is the most effective way to improve insulin control, keep blood sugar in check, reduce harmful cholesterol and lower blood pressure that is linked to type 2 diabetes and cardiovascular diseases. Exercising during pregnancy is perfectly safe and can promote a healthy baby and mother. However, a woman should not try to lose weight during pregnancy without first consulting with her doctor. A mother can reduce her post-labour risk of type 2 diabetes by 58 per cent by losing 7 per cent of her body weight and exercising moderately 30 minutes a day, five days a week. Dr Cory Couillard is an international health columnist that works in collaboration with the World Health Organization’s goals of disease prevention and control. Twitter: DrCoryCouillard