Is a wife considered to be in a state of nifas (postnatal bleeding) after miscarrying a six-and-a-half-week-old fetus whose limbs and head had begun to form?

The blood discharged due to a miscarriage is not considered nifas (post-natal bleeding) unless human features are discernable in the fetus. If this is not the case, then the blood is istihadha (irregular bleeding) which does not prevent prayer or fasting.