Was John the Baptist born without original sin?
The short answer
There is a pious speculation that John was freed from sin when he was filled with the Holy Spirit in the womb (cf. Luke 1:15, 41-44), but the Church has not declared it doctrine, and has not taught that he was baptized in the womb in the sense of ordinary baptism.
There is a pious Christian speculation that John the Baptist was freed from sin when he was filled with the Holy Spirit in his mother's womb (cf. Luke 1:15, 41-44). The Church has not declared this to be doctrine.
Nor has the Church taught that John was baptized in the womb, if that means the kind of baptism infants receive after birth.