The menses before giving birth to a baby was regular and lasts for six days every month. After giving birth to a baby, and after the end of the forty-day period, I was surprised by the discharge of blood of menses for two days only and then the blood stopped. So I waited for six days as usual and then I purified myself and performed the prayer. Then I had menses for another six days. This happened for two months consecutively. So is this the period of menses or is it a post period bleeding? Has my menses become thirteen days or should I purify myself and perform the prayer when the blood stops for the first time?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

If the blood discharges after the end of your post partum bleeding coincides with the period of your menses, it is menses, but if the blood does not coincide with your usual period, then it is a post period bleeding. The period during which you become pure between the two bleedings is considered as a pure period [you become pure in this period], so you should not abandon the prayer during it, and you are obliged to make up for the prayers you missed during this time. Since this situation happened twice in two months, this means that your menses has changed from six days to eight days (when all the days of menses are added together). There is nothing in what you mentioned which proves that your menses changed from six to thirteen days, as the period between the two bleeding is not considered as menses, but it is a pure period as discussed.

Allaah Knows best.