The father of Abd al-Rahman bin Abi al-Zinad (may Allah have mercy on him) says: I found the jurists of our (region), who followed the opinion of the Successors of the people of Madinah, saying (and he mentioned some rulings, among them) that prayer is not due from an unconscious person, unless he recovers while he is within the time of a prayer, in which case he will pray it; and he will make up the fasting. And if the unconscious person recovers before the sun sets, he will pray Zuhr and Asr, and if he recovers before dawn breaks, he should pray Maghrib and Isha. They said: The menstruating woman will also do the same when she becomes pure before the sun sets or before dawn breaks.
A musnad hadith has been narrated on this, and there is weakness in its chain. And Allah knows best.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 1819