Stephanie, aged 34, was reported missing on July 23 and was last seen on July 16 in the area of the main hospital in Newcastle city centre.
Officers have carried out extensive enquiries to locate her including a review of available CCTV and going door-to-door too.
Stephanie has links to Darlington and North Yorkshire.
She is described as a white woman, 5ft 5in tall of slim build with long dark brown hair.
Meanwhile, Gary, who is 65, has not been seen for several weeks. A search is underway for him too.
He was reported missing after his van was found near Aldi in the Newton Aycliffe area.
He has links to Whitby.