What is the ruling on aborting a fetus resulting from adultery with an atheist woman, knowing that the fetus is currently three months old, and is abortion permissible before 40 days or before four months, and what is the expiation for both cases?

The young man must sincerely repent and avoid everything that leads to indecency, such as unlawful seclusion. The jurists have agreed on the prohibition of abortion after the ensoulment, and the preponderant view among us is that it is impermissible at all stages. If the abortion occurs after 40 days, the blood money (diyya) for the fetus is obligatory, and it is more prudent to offer expiation (kaffara). The ruling on the impermissibility of abortion does not differ between a pregnancy resulting from unlawful sexual intercourse (zina) or a valid marriage. A child born from unlawful sexual intercourse is attributed to its mother, not to the fornicator. It is not permissible for a Muslim man to marry a disbelieving woman who is not from the People of the Book.