The book Babylon Mystery Religion by Ralph Woodrow, details how tunnels were discovered underground in monasteries for priests and convents for women, and how the children were buried in graves so that that nation would not discover the fact that the nuns and priests were covering up abortions. In many cases, the babies were killed by suffocation as confirmed by doctors....
The following article says that forty percent of Catholic nuns have been sexually abused by priests. If they got pregnant, their babies were murdered. I offer this article for your consideration, although I am skeptical about the source.