There are also credible pro-life arguments. The 14th amendment's Equal Protection clause is arguably provides the strongest legal basis for banning abortion: "nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."
So the legal question is whether a baby that hasn't yet been born is a person - if so, their life ought to be protected by state laws in the same way they protect anyone else's life.
It's a pretty straightforward question - is this baby an individual human being or not? I for one can't accept that I wasn't me while I was yet inside my mom (we know scientifically that after fertilization, I was a distinct human from my mom and dad) - and I see no reason to deny that personhood to fellow people. Answering in the affirmative, and various reasons for such an answer, forms the basis of the pro-life view.
Zooming out a bit, pro-life people see abortion as a modern analog to slavery in the US (where enslaved African-Americans were viewed as 3/5 of a person), except that unborn babies are viewed as not a person at all -- and this framing is used to justify killing them, not merely enslaving them and denying them the right to vote.