According to a new research, putting on too much weight while being pregnant can have results that last long after the pregnancy is over.

The results are perhaps no secret to new mothers who have to make great efforts to shed off that extra weight, but they are the first to confirm that these pounds might stick around for a long time.

There's proof that surplus weight gain in pregnancy, elevates the risk of obesity after delivery, but few studies have looked at the effects of weight gain on obesity risk for more than a couple of years after delivery.

Dr. Abdullah A. Mamun of the University of Queensland in Herston, Australia and associates observed the body mass index (BMI) in 2,055 women, who had delivered babies between 1981 and 1983. BMI is a standard measure of weight in relation to height, which is used to find out if a person is overweight or obese. The researchers employed 1990 Institute of Medicine suggestions on pregnancy weight gain that are based on a woman's pre-pregnancy BMI. The IOM revised these guidelines in 2009.

Women who had added too much weight during their pregnancy period, based on the IOM's previous guidelines had put on an average of around 20 kilograms (44 pounds) 21 years later, while women who added a healthy amount of weight put on 14 kilograms (31 pounds).

The relationship didn't change even after the researchers took account of factors like, whether a woman exercised during pregnancy or for how long she breastfed her baby.