BREASTFEEDING mums who enjoy the odd spliff could be getting their tots high, a study found.

Smoking cannabis leaves traces of the drug in breast milk for up to six days, it was revealed.

Researchers in San Diego, California, said that tetrahydrocannabinol, cannabis’s psychoactive compound, was present in 63 per cent of breast milk samples studied.

And cannabinoids, marijuana's active compounds, like to bind to fat molecules, which are abundant in breast milk.

Lead researcher Dr Christina Chambers said: "Paediatricians are often put into a challenging situation when a breastfeeding mother asks about the safety of marijuana use.

"We don't have strong, published data to support advising against use of marijuana while breastfeeding, and if women feel they have to choose, we run the risk of them deciding to stop breastfeeding - something we know is hugely beneficial for both mum and baby."

The team looked at 54 samples from 50 women who used cannabis.

The World Health Organization recommends exclusively breastfeeding a baby until is it six months old.

Breast milk has been shown to improve a baby's immune health and increased intelligence test results.