Is there a scriptural (naqli) legal proof that differentiates between the blood of a miscarried fetus that has formed (or had the soul breathed into it) and a miscarried fetus that had not formed before forty days?

The scholars differed regarding the beginning of nifas (postpartum bleeding). The Hanbalis and Hanafis held that it is established by the delivery of something in which the form of a human being becomes apparent. Whereas the Shafi'is held that it is established by the delivery of something in which the image of a human being appears, or what specialists determine to be human flesh. As for the Malikis, they held that nifas is established by the delivery of clotted blood that does not dissolve in hot water.