All perfect praise be to Allah, the Lord of the Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
Muslim jurists have two different opinions concerning the blood that a woman sees during pregnancy:
First: It is menstrual blood; thus, she shouldn`t pray and fast. This is the view of the Maliki jurists and the reliable opinion of the Shafies.
Al-Imam An-Nawawi (May Allah have mercy on him) said: "When the pregnant sees blood that has the same characteristics of menstrual blood and comes at the time when she really menstruates, then there are two famous opinions: The author of Al-Hawee, Al-Motawaalli, Al-Baghwee and others said that it is menstrual blood. This is according to the new opinion of the Shafie School.
However,according to their old opinion, it isn`t. Fellow scholars have agreed that the stronger opinion is that it is menstrual blood… Amongst the proofs that it is as such is that it has the characteristics of menstrual bleeding, itcomes at the time when a woman usually menstruates and there are two possibilities: blood due to sickness or menstruation, and, in principle, it is menstrual blood." {Al-Majmou`, vol.4/pp.412}.
Second: It isn`t menstrual blood. Rather, it is either an Istihadah {Irregular menstrual flow} or blood due to sickness. This is the view of the Hanfi and Shafie jurists. Ibn Quddamah (May Allah have mercy on him) said: "This view is based on the Hadith in which it was narrated from Ibn 'Umar that:he divorced his wife when she was menstruating, and 'Umar mentioned that to the Prophet (PBUH). He said: "Tell him to take her back then divorce her when she is pure (not menstruating) or pregnant." In this narration, pregnancy and purity indicate that she isn`t experiencing menstrual bleeding and when a woman gets pregnant, she doesn`t menstruate, and so the blood that she sees (during pregnancy) isn`t menstrual blood. Al-Imam Ahmad said, "A woman can tell that she is pregnant by the stoppage of her menstrual bleeding." {Al-Moghni, vol.1/pp.218}.
Nowadays, modern medicine affirms that the blood which a woman sees during pregnancy can`t be menstrual blood, because menstruation means the detachment of the endometrium after failure in the insemination of the ovum. If the ovum is inseminated and attached to the wall of the uterus, then the endometrium can`t be detached save with abortion.
Therefore, we (Iftaa` Department) adopt the old view of the Shafie school of thought as do the Hanafi and the Hanabali jurists: the pregnant should make ablution and pray, even if she sees blood. If the blood continues, then she should make ablution for every prayer at its due time. This is because the blood she is having is due to a sickness and not menstruation. We recommend that she visit a female doctor to receive the suitable treatment. And Allah Knows Best.