Nah he believes he can beat the crap out of all other alphas so he won’t get pregnant ╮(￣▽￣)╭
Jk, Tsugumi is a bit oblivious but that’s also his adorable point (I’m blinded)
it's explained in the recent chapter(s) that the reason he does not take the pills was because when he first tried it when he was younger, his body had a very negative reaction to the pills and I guess it felt worse than just not taking the pills so he decided to just deal with his heat so he doesn't have to go through that again. It could have just been his body adjusting to the pill and he would be fine if he took it now, but feeling that way as a kid really scared him.
AND HE DID
So the omega would rather risk of getting pregnant than taking those heat suppresant pills?? ok. That's something new there but is he a tsundere or just oblivious and adorably dumb???