To the best of my knowledge, the Church hasn’t defined one way or the other whether or not Mary suffered in childbirth. It is within the realm of acceptable theological opinion to hold either that Mary was free of childbirth pain because she was free of original sin; *or *that, even though she was not subject to this punishment of original sin, that she may have suffered it to be in deeper conformity to her suffering Son, Jesus Christ. Until the Church decides one way or the other, Catholics are free to hold either opinion.
Even so, Revelation 12 does not contradict the opinion that Mary may have been free of childbirth pain. For more information, please see the article linked below.
DISCLAIMER: Catholic Answers has turned over the archive to Catholic-Questions.org and no longer owns, manages, or moderates the forums. For additional apologetics resources please visit www.catholic.com.