A pregnant woman and her unborn baby have died after a suspected snake bite in the Mid-West WA town of Meekatharra, 775 kilometres north-east of Perth.

St John Ambulance officers were called to a home in Main Street at 8.43pm on Monday.

It was reported the woman, in her 20s, had been bitten while outside her home and began fitting.

She alerted family members who called emergency services.

The woman was taken to Meekatharra Hospital but died shortly after arrival.

Despite their best efforts, doctors were unable to save her unborn baby.

Her body will be taken to Perth for a post-mortem examination but it could take some months to determine the exact cause of death and type of bite.

Police are preparing a report for the coroner.