Being adamantly pro-choice means you support abortion on demand and most likely you also support Roe v Wade. Reagan never supported Roe v Wade and its judicially legislated provision granting legality to abortion on demand.
The 1967 Therapeutic Abortion Act that Reagan signed into law did not grant abortions on demand. It was specific to the exceptions of substantial risk that would gravely impair the physical or mental health of the woman, along with rape and incest. It was advertised as a compassionate law that would be used to deal with the difficult abortion cases. Reagan was firmly in the prolife camp and adamantly opposed to most abortions in 1967. Reagan was pro-life until his death and publicly spoke out against Roe v Wade, calling it infanticide.
Reagan had been apprehensive about signing the law. He was afraid it would be abused. Within a year of passage abortions were being performed for most any reason.
Reagan said, "The reform law was based upon policing by the medical profession itself. Committees — medical and psychiatric — were to determine whether the individual wanting the abortion met the requirement of endangered health, life, mental health and so forth. I think it is very apparent that people are literally getting abortions on demand."
This is in the context of a pre-Roe v. Wade world, nevertheless, I’d say that if Reagan had doubts about abuses then he should have not signed the legislation. I’m not being critical of Reagan, governors and presidents have to make tough decisions everyday and it’s not possible to get them all right. You just hope that they get the big ones right; often times it’s many, many years later before you know if it was right.