Very large fundal height, not polyhydramnios

I’m 34 weeks and my midwife measured my fundal height as 41wks. That’s a pretty big discrepancy. It’s not polyhydramnios because I had a scan and everything looks fine. The baby is also not massive. What else could it be?! Is it possible that maybe I’ve gained a lot of fat around my belly or something? I’m very relieved that it’s not polyhydramnios so I’m not feeling anxious, just curious and wondering if anyone had anything similar.