Petra Hansen b. 1868

My g.f. born to this woman, Petra Hansen on the Bilet farm, Fredrikstad, in 1896. Would appreciate efforts to locate any other information about her. G.F given to foster parents to raise. We have no understanding of what became of her after my g.f.'s birth in 1896. HIS baptismal indicates she was born in 1868. Can anyone find any other records for her[?] Thanks so much. Regards KAnnie