Swaddling has been widely used in many cultures globally. It is thought the blanket wrapping can simulate the feelings of being in the womb and calm the child.

But the technique holds the legs out straight and restricts movement, which can alter the development of the hip joint.

New research suggests that swaddling is partly responsible for hip dysplasia.

Writing in the journal Archives of Disease in Childhood, Prof Clarke argued: "In order to allow for healthy hip development, legs should be able to bend up and out at the hips. This position allows for natural development of the hip joints. The babies' legs should not be tightly wrapped in extension and pressed together."

Jane Munro, of the Royal College of Midwives, said it was a "seemingly innocuous" thing to swaddle babies, but it posed "significant problems" for the baby. She said there was also the risk of the baby overheating and a raised risk of cot death.

Baby sleeping bags are designed in a way to allow lots of room for leg movement and do not restrict or straighten baby’s legs. At the same time they keep babies calm and safe, overheating is greatly reduced. Midwives recommend the usage of baby sleeping bags from birth.

At Slumbersac there are two sizes of baby sleep sacks available for new-borns: 56cm for small babies with birth weight below 4 kg and 70 cm for babies with a minimum birth weight of 70cm. When choosing a baby sleeping bag for your new-born make sure its head cannot pass through the neck opening.

Used correctly baby sleeping bags reduce the risk of overheating and cot death and promote healthy development of baby’s hips.