The number of abortions reduces after a visit by the Pope in the area because his presence makes people have less unprotected sex, according to researchers.
A study suggests abortion rates usually fall by a fifth for up to 14 months after a papal visit but the birth rate stays the same.
Scientists led by a team from the University of Sussex team looked at 129 official visits made to 85 Italian provinces by Popes John Paul II and Benedict XVI between 1979 and 2012.
It does not include visits by Pope Francis, who became head of the Catholic Church in 2013.
Scientists conclude that the Pope's message must have driven the trend, inspiring local women to take a vow of chastity, or an increase in the use of contraception.
Study co-author Dr Vikram Pathania said: "While use of contraception is also contrary to Catholic teaching, it may be viewed as the lesser of two evils when compared to abortion."
Popes John Paul II and Benedict XVI mentioned abortions in a quarter of visits during the period.
The team also found that the Pope influenced sex much more than churchgoing.
Previous studies found women go to church more often for three months after a visit - with no increase for men.