Is it permissible to fast the ten days of Thul-Hijjah with the intention of making up the days of Ramadan that one missed, knowing that I gave birth on the 3rd of Ramadan?

All perfect praise be to Allah, The Lord of the Worlds. I testify that none is worthy of worship except Allah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and messenger.

It is permissible for a Muslim to fast during the ten days of Thul-Hijjah with the intention of making up what he missed of Ramadan.

However, if he wants to combine two acts of worship with one intention, i.e. fast during the ten days of Thul-Hijjah with the intention of making up for the fasts of Ramadan that he missed along with the intention of fasting the ten days, then this is not valid. That is because doing this implies combining two acts of worship, one of which is intended separately for itself.

Allah Knows best.