So, let's break down this "insurance" idea a little more.
If they're Ukrainian Citizens living in Ukraine, they would have had health care covered through Ukraine's national health plan, like any other citizens, paid through a tax on earnings. Ukraine is not a part of the EU, so they likely wouldn't have had reciprocal coverage with other European countries. But to be honest, most Europeans that I know don't even think about "health insurance" when they travel. It's really, really not a thing people consider here -- they assume that they can go to a doctor on the state health care system when they travel, and pay a low or not fee. And frankly, you can! I got a perforated ear drum in France in January, and when I tried to pay the doctor for treatment (as an American Citizen living in the EU with no EU Health Care) they shrugged and sent me out the door. (I did have to pay for the meds at the Pharmacy).
So, while traveler's insurance policies exist, I think it would be really unlikely that they would have considered getting one. Some people do get them for travel to the US, but that's mainly because our health system is so horrifically and legendarily bad that even non-savvy travelers know they're up the fecal estuary if they get so much as a cold. If they DID get a traveler's policy -- and I say this as someone who buys them regularly -- functionally all of them would exclude pregnancy as a covered condition, and would not cover the baby until it was born and could be underwritten. Obviously, a premature newborn in need of $230k of care is not going to pass underwriting for any insurance policy, so it's a bit of a moot point. (This is one of the reasons that pregnant women are not recommended to travel internationally late in pregnancy.)
tl;dr: Should they have had insurance? Probably. Would it have helped in this case? Almost certainly not.