Having sexual intercourse after taking Ghusl, then seeing blood

A: A menstruating woman should not have Ghusl until she sees the sign of Tuhr (purity from menses signaled by white discharge or complete cessation of bleeding). It is not permissible for her husband to have sexual intercourse with her until her menses completely stops, and she has Ghusl and becomes Tahir (ritually pure). Allah (Exalted be He) says: They ask you concerning menstruation. Say: that is an Adha (a harmful thing for a husband to have a sexual intercourse with his wife while she is having her menses), therefore keep away from women during menses and go not unto them till they are purified (from menses and have taken a bath). And when they have purified themselves, then go in unto them as Allâh has ordained for you (go in unto them in any manner as long as it is in their vagina). In your case, you should offer Tawbah (repentance to Allah) and Kaffarah (expiation), which is to give in charity what is equal to one or half a Dinar of gold. The Dinar equals 4/7th of one Saudi pound according to the exchange rate of Dirhams.May Allah grant us success. May peace and blessings be upon our Prophet Muhammad, his family, and Companions.