It isn't the only way and they say as much (specifically that it isn't uncommon, which means natural birth happens too). It's common even in the real world for mothers of multiples to require a c-section due to complications.
I don't know about you, but most people in my country prefer natural method to a c section. And, well while C section is common even in real world, in omega world it's.... probably the only method that probably don't make reader question their sanity. I know there will probably be natural birth too,( most certainly with female beta or omega) but imagining the baby born from male omega naturally..... okay, I'll stop talking.
I've read a comment once said that they wonder about how the baby in omega world is born..... welll, I guess they got their answer now.