I'm not sure. If you read the story, she has a nine year old daughter, so presumably she got pregnant naturally aged 56, which would be older than the limit Jonaj and EricaL are suggesting. It's also worth noting that she had IVF not AI (two very different treatments) and that both are illegal in her home country at her age anyway, and all that happened is she went to another country with different laws. Making things like this illegal just tends to send it underground (think of countries where abortion is illegal) so women are being treated in dangerous conditions and by unqualified people; or sends people abroad to countries where standards are often lower - so if this woman had been treated in Germany, she might well be pregnant but definitely not with four babies, as more careful treatment would have prevented that.
I think that some leeway is needed and that a draconian "nothing after this age" can cause more problems than it prevents. There have been cases of grandmothers becoming pregnant with their daughter's baby, where the daughter was unable to bear a child. A blanket ban based on age would prevent this and that doesn't seem fair to me. I can think of other cases where it might be acceptable for an older woman to become pregnant. So I think doctors should have the ability to make a decision on a case by case basis.