Ah, totally get your worry! The good news is cefuroxime is actually a cephalosporin, same class as cephalexin, and honestly, a lot of preggy moms I know have taken it without issues kaya common siya dine sa OBs. Since it doesn't transfer much to baby at mababa ang risk, maraming doctors prescribe it especially for cough and sinus stuff na di mawawala sarili. Your OB knows your situation best, so if she chose that for you, it's a sign na safe siya sa 18 weeks mo. The thing is, leaving an infection untreated while pregnant can actually be harder on you and baby than the antibiotic itself, so it's kind of a "take it so you heal faster" situation. Someone in my mum group mentioned na they felt so much better after the course na worth it talaga, and walang issues sa baby. That said, worth double-checking with your OB ulit if you're still nervous, she can walk you through why she picked that one specifically for you, which sometimes makes the worry easier. You've got this!