It would appear that Wu Wuyan had swapped bodies with Lan Waihu. Given the difficulties that Lan Waihu had to go through to get pregnant, Gu Xijiu did not want her body to get damaged. She had to do her best to drive Wu Wuyan soul out so that Little Fox could return to this body.
She secretly clenched her fists in her sleeves as she was frustrated that she had not learned how to switch people's souls and bodies. Therefore, she had to wait for Di Fuyi to arrive. She had thought of a thousand other ideas in her mind of the best way to get Wu Wuyan out of Lan Waihu's body.