K.B.
As everyone has said already...it is normal.
My son went through a no bath phase but also he refused to eat as well. He would scream and run out of the bathroom as soon as I turned the water on.
I found that a lot of the issue was really ME!
I realized that he was refusing to do things because he felt like he had no say in the situation.
Once I started to give him the choice to take a bath (or eat certain foods)instead of expecting him to do it "because I said so!"the stress and struggle went away.
Also your daughter is at an age where she can understand, if you explain it to her simply, she needs to take a bath because she is dirty. Children don't need a bath every night and as long as my son wasn't filthy dirty I didn't worry about it. I would also give him the choice of a bath or a washing with a washcloth to get the dirty parts clean. He usually went with the bath if I gave him that choice but if he wasn't really dirty I would just ask him if he wanted a bath and if he said no I left the issue alone.
As another poster said... Do what makes it easier on you but keep in mind that your daughter probably feels like she is very limited by her world, with what she can and can't do, and to give her choices such as what to wear, if she wants to take a bath, what she wants for a snack etc..will help with struggles in the future because you will be giving her some sense of independence and accomplishment.
Good luck and congratulations on the pregnancy.