Musannaf Ibn Abi Shaybah 19417 — A man who says to his wife: if you

Qatadah (may Allah have mercy on him) said: If a man says to his wife, "When you become pregnant, you are divorced," then he should have intercourse with her once in each period of purity and then not have intercourse with her again until she becomes pure after her next menses; when her pregnancy becomes evident, she is irrevocably separated.