New child growth charts are being advocated in the UK which accurately reflect the slower weight gain associated with breastfeeding.
Child growth charts currently in use in the UK and in many countries are 20 years old and based on predominantly formula-fed babies, who tend to grow more quickly.
Experts believe the charts are a cause for concern as they lead breastfeeding mothers to feel their babies are not thriving because they do not gain weight fast enough.
The new child growth charts were drawn up by the World Health Organization and have the backing of the Scientific Advisory Committee on Nutrition and the Royal College of Paediatrics and Child Health.
It is hoped that the new standards will help alleviate mothers' concerns regarding the difference in growth patterns often seen between breastfed and formula-fed babies.
The WHO charts are recommended to be used for babies aged two weeks to 24 months and though they are based on breastfed babies, they are designed to assess and monitor the growth of all babies.
Experts agree that breast milk is the best source of nutrition for babies and the Department of Health recommends exclusive breastfeeding up to the age of six months.
The WHO charts are based on a select group of 8,000 babies from six cities around the world, who were entirely breastfed for six months, with continued breastfeeding into their second year, and where none of the families smoked.
Babies who are breastfed gain weight at a slower rate than their formula-fed peers and research suggests that such a pattern of growth could potentially reduce the risk of later obesity.
The new charts will advocate a lower range of 'healthy' weights for all babies, with fewer deemed to be underweight at any age.
Under the existing charts a healthy one-year-old weighs between 22.5lb and 28.5lb but the new chart says the ideal range is from 21lb and 26lb.
Child experts believe that if the new charts are adopted in the UK a quarter of all babies will be redefined as heavier than the norm.
A pilot study will be the forerunner of the adoption of the new charts to assess the practical aspects of their implementation.