After sex itching

I know this sounds weird but in my crazy brain it makes sense. Lol. I’m 24 weeks pregnant with our son and literally every time my husband and I have sex, I itch like crazy down there for the next day or two. Is it possible for his semen to be clashing with my hormones and ph balance and throwing things off? He doesn’t pull out obviously because I’m pregnant. We don’t use lube or anything because, well it’s slippery enough since I’m pregnant. We haven’t changed soaps or anything so all I can figure up is that maybe my hormones are messing with the ph balance and his stuff doesn’t help. I don’t have any funky colors or smells going on down there, just insane itching after sex and it’s embarrassing if he catches me scratching lol. Maybe I could have him pull out and see if it helps? Has anyone else experienced this?