Ikrimah (may Allah have mercy on him) said: "Ghayz refers to menstruation occurring during pregnancy, and for every day that passes in the state of menstruation, one day is added to her pregnancy until she completes the pregnancy in a state of purity."
Hadith Referenceسنن سعید بن منصور / كتاب التفسير / 1157
Hadith Gradingمحدثین:سنده صحيح.
Hadith Takhrij«أخرجه الدارمي فى (مسنده) برقم: 963، 965، وسعيد بن منصور فى (سننه) برقم: 1157»