First and foremost, man (includeds women) is not as much a rational creature as a rationalizing creature. A young lady finding herself pregnant, is likely to rationalize a LOT. Secondly, when some of them say "My parents are going to kill me" or "If I change my position, my parents will kick me out of the house" it's not hyperboly. They believe that. My experience may be somewhat outdated, but I suspect that human nature doesn't change that much in a few decades.
When I was in high school, late 60's, abortion was illegal in Ohio, with the weasal words that an abortion could be legally performed if the woman was at risk. I had occasion to find a doctor that was partnered, informally, with a brain squeezer, who would state that the girl in question would harm herself if required to take the fetus to term. That made it legal. My girlfriend and I directed a number of friends and acquaintances through that system. At the time, I wasn't aware of pro/anti choice movements. We regarded it as a social necessity. I was suprised at how ambivalent some of the girls were about it. They were truly confused. They should probably have had better advise than that provided by my sweetie and I. In any event, by 1970 or so, it was legal in New York, and the demand dropped. Somewhat later, abortion was legal in Ohio, and it was no long necessary to go through those kind of hoops any more.
I have a sneaking suspicion that those times are comng back again.