Can I Prevent Italicizing Type from Changings the Leading (Line Spacing)?

Working in iBooks Author, I have text in the Regular or Book version of a typeface. When I italicize a word, the leading of the line it's in changes, sending the line below a skosh below where it had been before the italicizing of the word above. If I italicize a wholr paragraph or more, the lading of all the italicized lines shrinks. Am I stuck with this in all my iBooks? Or have I discovered another weird anomaly of iBooks, and another reason to prefer making print books?