Contraceptives sometimes fail. Sometimes you make a really bad judgement call. Sometimes the guy might be an asshole intentionally break/remove the condom. Sometimes bad things happen.

Not everybody is comfortable with using abortions to deal with unplanned pregnancies even if it is the financially expedient thing to do.

Well, twins probably would have been a surprise. That's probably what the article was referring to; who expects twins?

Twins are unexpected, but surely they knew at least one child will be born? Even one extra is a huge commitment when you don't have the means.

Read the quote carefully. IMO it is not saying that the pregnancy was a surprise, but that twins was a surprise.

Which is exactly my point.

Twins are much more common among people using fertility drugs than the majority of the population; so if you are on those drugs, you might expect them.

P.S. not trying to be snarky, just thought it was an interesting fact