He had called himself “pro-choice” when he was about to become Vice President of the United States. But as President he was strongly against abortion, This article explains how he changed.
–From a report on what this change meant:
After his change in his view of abortion "as President, he directed his attorney general to ask the Supreme Court to overrule its pro-abortion decisions in Roe v. Wade and a later case that reaffirmed Roe’s holdings, Webster v. Reproductive Health Services.
President Bush worked to limit Title X funds from going to organizations that promote abortion and maintained the Mexico City policy, which stops U.S. taxpayer funding of the abortion industry overseas.
President Bush also used his veto pen to protect unborn babies. He vetoed an entire spending bill when congressional Democrats sought to loosen the Hyde Amendment. Overall, he lodged 10 vetoes of bills that lacked protections for the unborn.
And he issued sanctity of life proclamations annually.
(From an article at https://www.lifenews.com/2018/12/05/the-amazing-story-of-how-president-george-h-w-bush-became-pro-life/ )