I've read other Omegaverse and Alphas can do get pregnant but their fertility rate to give birth is low which is why Omegas have a big role when an Alpha needs a sucessor.
I think it depends on the author and how they want to portray the universe. I’ve seen male alpha’s being able to get pregnant In some, and I’ve seen others where it’s said that only male omegas are the only male that can get pregnant.
I've read other Omegaverse and Alphas can do get pregnant but their fertility rate to give birth is low which is why Omegas have a big role when an Alpha needs a sucessor.