Scientists say this is because tiny glands on the breast produce a fluid with a smell that attracts babies.
The findings reveal newborns fed more and put on more weight when feeding from mothers who had lots of the glands, which are the small bumps around the nipple.
Scientists claim this scent could be used to teach tube-fed premature babies how to breastfeed.
It is believed this would mean that when babies are able to feed naturally, they would find it easier.
Benoist Schaal, from the National Centre for Scientific Research in Dijon, led the research and said the discovery could lead to the chemicals that make up the smell being bottled.
‘It could help prepare the babies for the transition from tube-feeding to direct sucking on the nipple of a mother or bottle,’ he said.
The number of glands, which can produce a small amount of liquid, often increase during pregnancy.
It has been widely thought that the liquid lubricates the skin.
And previous studies have shown that newborns prefer to feed from an unwashed breast to a clean one.
But the study, published in
New Scientist magazine, is the first to show that the fluid from the glands may attract babies.
A total of 121 mothers were involved in the study, in which French researchers counted the number of glands on their nipples three days after birth.
They recorded how well the babies suckled, as well as how much they weighed.
The results also revealed that mothers with more than nine glands on each breast started to produce milk sooner than those with fewer glands.
They also showed that the effect was increased for first-time mothers.
