Just one unit increase in BMI between pregnancies doubles a woman's diabetes risk, new research reveals.
Gaining between two and four units increases a woman's risk of developing gestational diabetes mellitus (GDM) by 2.6 times, a study found.
The increased risk is strongest in women who had a BMI of less than 25kg/m2 in their first pregnancy, the study found.
Evidence of a preventive effect occurs in overweight women who reduce their weight by two or more BMI units between pregnancies.
GDM is high blood sugar that develops during pregnancy and usually disappears after giving birth.
Just one unit increase in BMI between pregnancies doubles a woman's diabetes risk (stock)
Taking fish oil in pregnancy may reduce a child's risk of diabetes, research suggested last month.
Giving overweight pregnant rats fresh fish oil improves their offspring's response to insulin, a study found.
Previous research has demonstrated insulin sensitivity is protective against diabetes.
Lead author Dr Ben Albert from the University of Auckland, said: 'This is exciting because it raises the question: if overweight women take fresh fish oil in pregnancy, will it lower the risk of their children later developing diabetes?'
Yet, researchers advise women eat more oily fish rather than taking fish oil as some supplements are of dubious quality.
Gaining four BMI