A New South Wales mother has won a legal battle to breastfeed her 11-month-old boy after the Family Court overturned a court-ordered injunction.

The 20-year-old, known by the pseudonym Ms Jackson for legal reasons, was ordered in early June to refrain from breastfeeding her baby on the grounds that she had recently been tattooed and might transmit a blood-borne disease such as hepatitis or HIV to the infant.

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The full bench of the Family Court unanimously overturned the decision on Friday, finding the judge who presided over the initial hearing, Matthew Myers, made the order based on evidence that “should not have been relied upon”.

This included information from organisations such as the Australian Breastfeeding Association that Judge Myers found while surfing the web, rather than expert testimony, Justice Murray Aldridge said in his judgment.

He added that the case appeared to have “the flavour of” prejudgment and cautioned judges not to mistake “their own views for facts”.

The court earlier heard Ms Jackson had tested negative to HIV but was considered by Judge Myers to remain within a time window during which a positive result may yet show up.

But Justice Aldridge said the risk to the baby “must be regarded as low” and that the injunction had failed to recognise the importance of breastfeeding to mother-child bonding.

The court earlier heard Judge Myers had originally suggested Ms Jackson should refrain from breastfeeding because of issues connected with medication she was taking to treat post-natal depression.

Court transcripts were read out in which Judge Myers told the mother, on the first day of a two-day hearing, “Don’t breastfeed anymore. Seriously. It’s not in the best interests of the child.”

He also said he did not care if his injunction attracted adverse media attention, saying, “I will do it. I don’t care whether it hits the front page.”

In considering the court’s decision, Justice Aldridge said he and fellow justices Judith Ryan and Hillary Hannam had been able to find only one breastfeeding injunction, which dated back to 1999.

That ruling, involving a mother who was HIV positive, “is an entirely different case”, he said.

He said the issue of breastfeeding had not been driven by the baby’s father, but rather that there was a “real sense” that the issue “was being driven by the trial judge”.