The threshold, legally, is viability. But even when abortion was illegal and a "Sin" (like extra-maritial sex) - it still happened. Pennyroyal tea... Staircases, and coathangers were all considered options - by desperate women, unprepared to raise a child.
Even with legal abortion - there are plenty of children left in orphanages and Foster Care - and their outlooks and outcomes aren't great statistically. The Foster Care system tends to graduate out to homelessness. And often those kids have short life-expectancies, from that point.
I don't "support" abortion per se... But I think that women need to be given safe options when that's the direction they've decided to go. Ironically... GOP mistresses from "Right-to-Life" States - are well provided for, in that department. The same Congressmen and Senators who rail against abortion - will put someone on a plane - when they need one. Which means that it's most likely the poorest and most unprepared women being forced to have unplanned children, in places like Texas, Kansas or Oklahoma. And once born - do those States provide well for them? Healthcare and education seem to get short shrift in our society - compared to Police and Prisons.
Planned Parenthood is also where poor women seek healthcare of ALL sorts - mammograms, STI-checks, OB-GYN and Birth Control - are actually the vast majority of their business. The idea that they are just abortion-mills - is why they've been defunded by the GOP congress - leaving poor women with scant options in many areas.
I'm against abortion - but pro-choice, for those who're unprepared to raise a child, and pregnant.
And there's also the usual set of outliers - that even some Right-to-Life States recognize - Rape, Incest, and life of the Mother (Ectopic pregnancies, for example).
In California, we allow abortions - but we also believe in good schools and healthcare - so that people can afford to raise the children they have.