Is a husband's divorce of his wife considered a Bid'i divorce or a Sunnah divorce if she has not had her menstrual period for 10 months after childbirth?

Divorce during a period of purity in which a man has had intercourse with his wife is an innovated divorce (talaq bid'i), whether that period of purity is long or short. The basis for this is that the Prophet, peace and blessings be upon him, ordered Ibn Umar to take back his wife whom he had divorced while she was menstruating, and he instructed him to divorce her when she was pure and he had not had intercourse with her, or when she was pregnant. This is the lawful divorce (talaq shar'i). As for divorcing her while she is menstruating, or in postpartum bleeding (nifas), or during a period of purity in which he had intercourse with her and her pregnancy was not yet apparent, this is an innovated divorce (talaq bid'i). And despite it being innovated, it is still valid.