The Difference Between Menstruation and Post-Natal Bleeding

The Shaykh : However, the difference between menstruation and post-natal bleeding is that menstruation is blood of nature and constitution that comes out of a female when she reaches puberty. The scholars said: Allah created it for a wisdom, which is the nourishment of the child, the fetus, in her womb, for it feeds on it. This is why we find that a pregnant woman, in most cases, does not menstruate. When the woman gives birth, this [blood] turns into milk. This is why we find that a nursing woman, in most cases, does not menstruate, because that [blood] turns into milk. This is from the wisdom of Allah: when the child was in the womb, its nourishment was blood in which there are no excretions coming out of the fetus. When it came out, its nourishment became milk. It is not obligatory for the menstruating woman or the woman with post-natal bleeding to fast, but they must make up the fasts.