What is the ruling on a man having intercourse with his wife when he sees a small spot of blood at the beginning of menstruation and before the abundant flow of blood?

It is not permissible for a man to have sexual intercourse with his wife during menstruation, whether at its beginning or its end, and whether the bleeding is heavy or light. Whoever does so must repent and seek forgiveness. According to the majority of scholars, there is no expiation (kaffarah (definition)) required for him, while the Hanbalis hold that it is obligatory to give half a dinar in charity as expiation, and this expiation is waived if one is unable to do so. What is incumbent upon the man is also incumbent upon his wife if she is compliant, but there is nothing upon her if she is coerced.