“I once said to abu ‘Abd Allah (a.s.), that I may purchase a slave-girl. Her Hayd (menses) stops because of spoiled blood or some kind of air in her womb, and she uses medicine for cure and her Hayd (menses) begins on the same day. I do not know if it is because of pregnancy or for other reasons, is it (use of medicine) permissible? He (the Imam) said, ‘You must not (allow to) do so? I then said that her Hayd (menses) has stopped for a month. Were it because of pregnancy, it would be a seed like the seed of man for which he may use contraceptives. He (the Imam) said, ‘If the seed falls inside the womb, it changes into a lump, then into flesh, then into what Allah wills. If the seed (semen) falls in places other than the womb nothing is created thereof. You must not give her medicine, when her Hayd (menses) stops, for a month and her time of Hayd (menses) passes?” (Fatwa best explains the above Hadith; it deals with several issues such as contraceptives, liability for abortion and the stages of fetuses.)