Husband on medicine

So, my husband is on beta blockers because his heart. It’s not specific for his blood pressure because he has a rare heart thing where his system is off slightly than normal. His system is “resetting” with the medicine! It’s taken us THREEEE cardiologists to get the right answers and medicine. So I’ve read it reduces sperm in a few ways but has anybody gotten pregnant while theyre on them?! I’m hoping by November he’s off of them but after two years I’m starting to feel so hopeless.