A 40-year-old Melbourne, Australia, woman who had a sexual relationship with her child's 12-year-old friend, spanning a period of five months, will spend at least six years in prison after she gave birth to the boy's child.

The woman who has been jailed on charges of child abuse, was said to be having unprotected sex with the boy at least once a week over the period.

The woman who cannot be named, was sentenced at the Victorian County Court after she had pleaded guilty to the persistent sexual abuse of a child under the age of 16 over her relationship with the boy, who was her daughter's friend.

She however admitted she started developing feelings for the boy and began a sexual relationship with him.

In May of 2014, the woman gave birth to a girl after telling the boy she thought the baby was his. The boy's mother visited the woman in hospital to support her but was unaware her son was the father and she was the grandmother.

Shortly afterwards the boys' parents found out about the relationship and confronted the woman and reported her to police and a DNA test confirmed the boy is the baby's father.

In sentencing her, the angry judge lashed out at her:

"You failed to recognise that your feelings for the boy were completely inappropriate. You commenced and continued an abusive sexual relationship.

You have allowed your physical and emotional urges overcome what should have been the proper adult response."