The dogma reads as follows: “Mary bore her Son without any violation of her virginal integrity”. As Catholics we are bound to believe only that statement. Dr. Ludwin Ott in Fundamentals of Catholic Dogma pg. 205 says that “the dogma merely asserts the fact of the continuance of Mary’s physical virginity without determining more closely how this is to be physiologically explained”.
But while many of the Church Fathers (few exceptions) did hold to the belief that “Mary gave birth in miraculous fashion without opening of the womb and injury to the hymen, and consequently experienced no pain” (Ibid, pg. 205), that is not part of the dogma and, thus, there is no obligation to believe it.
For more information on this subject I recommend the following:
Stanley Jaki’s booklet, The Virgin Birth and the Birth of Science
Father Stefano Manelli’s book *All Generations Shall Call Me Blessed *
