I never really found this to be a good argument, honestly. You could use the same logic to say that it's okay to commit murder because people die in accidents all the time. That success rate could be 100% and abortion would still be fine because a fetus isn't a person.
Yeah a lot of attempts to debate pro-lifers end up conceding to them the idea that abortion is murder but then just try and debate that actually it's justified. The real argument is that no it's stupid to act like destroying something that has the potential to become a fully developed person is the same as killing a fully developed person, if it was jacking off and having a period would be mass murder.
It's not a standalone argument. It says that if you believe that life begins at conception, then you believe the vast majority of people who have birthed children are guilty of manslaughter. And I think that illustration is a good way to open up how preposterous it is to equate a handful of cells to a breathing, dreaming, social human being.
Or that if life begins by conception, then by far, the biggest killer of people is miscarriage, or eggs failing to implant in the uterus. There's not a single disease or regime on Earth that comes close to killing as many people as miscarriage. But there's no marches to research a cure for miscarriage. No candlelight vigils for them.