What are the rulings concerning a husband's intercourse with his wife four days before her menstrual period, given that the wife saw a faint, light color for two days before the usual signs of menstruation appeared?

If a woman finds a brownish discharge (kudrah) during the period when menstruation is possible (i.e., after fifteen days from the end of the previous cycle), it is considered menstruation, even if it appears before her usual time. This is according to the madhhabs of the Malikis and Shafi'is, and those who agree with them. If a man intentionally has intercourse with his menstruating wife, he has committed something forbidden and must repent to Allah. The same ruling applies to the wife if she is compliant, but there is no sin upon her if she was coerced.