Disturbance of the Monthly Menstrual Cycle

Question:

I am a forty-two year old woman, and sometimes my monthly period lasts for four days, then it stops for three days, then on the seventh day, it starts again, lighter than before, then it (the discharge) turns brown until the twelfth day, and I have been suffering from a bleeding condition, but it has stopped following treatment-all praise and thanks be to Allah. I consulted a religious righteous doctor about the above mentioned condition, and he recommended me to make Taharah after the fourth day and to perform my acts of worship-prayer and fasting. And actually, I continued to do as the doctor had advised me for a period of two years, but some women said I should wait for eight days...so I request your Excellency to guide me to the truth.

Answer:

All of the days mentioned, four and eight are days of al-Haidh, so you should leave prayer and fasting during them, and it is not lawful for your husband to have intercourse with you during the days mentioned. You should make ghusl after four days and pray and you will be permitted to your husband during the period of Taharah from the fourth day and the eighth day, and there is no objection to you fasting during them.
If it be during Ramadhan, it is obligatory for you to fast, and once you have purified yourself from the eighth days, you must make Ghusl, pray and fast like the rest of the purified women, because the monthly cycle - that is, the menstrual period - increases and decreases, and the days are (sometimes) joined and (sometimes) broken up.

Source:
Shaykh `Abdul-`Azeez Bin Baz
Fatawa Islamiyah, vol.1, p113-114, DARUSSALAM.