Experts have said that three to 12 months after birth is the key time to start losing the "baby weight", as the excess weight not lost after a year poses health risks.
The Canadian researchers have said that mothers who fail to lose excess weight within a year after delivery or gain weight may be risking their health and have higher blood pressure and other risk factors for later diabetes and heart disease, the BBC reported.
Dr Ravi Retnakaran, the diabetes researcher and clinician who led the study, said that most women are not going to go back to their pre-pregnancy weight right away and they have found that the typical pattern is more than 80 percent don't by three months.
The research found that the elevated risk factors seen one year after giving birth are not present at three months after childbirth and not losing the weight one year after birth is a stronger predictor of the likelihood of being overweight 15 years.
The research was published in Diabetes care.