Practically speaking, yes, 99.99999% of creatures wouldn't last a literal second against Bahamut, but gods in the Faerun pantheon are not omnipotent, or invincible. He could be harmed or even killed, but there are very few creatures who could do it. A large party of level 20 adventurers could possibly pull it off, but at that level they're effectively demigods in their own right.
Or Ao could just decide to replace him or give his portfolio to another lawful good god, snap his fingers, and even Bahamut would instantly pop out of existence.
Banning abortion doesn't stop abortion, it just shifts it to a black market where women are far more likely to die.
What does demonstrably reduce abortion to effectively insignificant levels is better sex education and easy access to contraceptives.
Prohibition has never worked. Education always has.