Musannaf Ibn Abi Shayba 3:4856

Abu Bakr narrated to us, he said: Ibn ‘Ayyash narrated to us, from Ibn Mughira, from al-Sha’bi, who said: If the time for prayer enters for a woman, and she does not pray until she begins her menses, while she was within the time of the prayer, she shall make it up when she becomes pure.