What is the ruling on a woman who sees red blood for a period exceeding her usual menstrual cycle, and what is the ruling on her husband having intercourse with her during that period?

The menstrual period may increase or decrease. Whatever blood a woman sees that is connected to her usual period is considered menses, as long as it does not exceed fifteen days. Otherwise, it is istihada (non-menstrual vaginal bleeding). Yellowish or brownish discharge after purification is not considered menses.

A woman experiencing istihada can fast and pray. She should perform ablution (tahara) for prayer after the time for that prayer has begun. She is permitted to combine the Dhuhr and Asr prayers, and the Maghrib and Isha prayers. She has the choice between combining them at the time of the earlier prayer (jam' al-taqdim) or at the time of the later prayer (jam' al-ta'khir). She should not pray two obligatory prayers with a single ablution if they are not combined. She may pray the obligatory prayer and as many supererogatory (nafl) prayers as she wishes. It is preferable that her husband does not approach her during the period of istihada, unless it is prolonged.