Good question! The tradition is that Jesus’s birth was painless. St. Thomas Aquinas makes the argument for it in his Summa Theologica.
It generally is argued that as the pains of childbirth are a consequence of original sin from which Mary was preserved from, she did not suffer the pains of childbirth.
That being said, this is not a dogmatic teaching necessary for salvation, and some difference of opinion may be held on this point, so long as no opinion held violates dogmatic teaching necessary for salvation. (ex. That Mary bore her Son without any violation of her virginal integrity. (De fide on the ground of the general promulgation of doctrine) and After the Birth of Jesus Mary remained a Virgin. (De fide.))
Does this help? God bless!