The National Right to Life Committee and NARAL Pro-Choice America have each released reports on the Republican field of presidential candidates. They agree that all of the most prominent candidates oppose abortion. It appears that pro-life groups have mostly forgiven Romney's earlier opposition to prenatal rights-- and that his former pro-choice supporters have officially bailed on him. (Neither group bothered to address pro-abortion Republican and former governor of New Mexico Gary Johnson.)
As a consequence, the right to life is unlikely to be an issue during the primaries. NRLC and other pro-life organizations are declining to endorse a candidate at this time.