Your hormone levels rise again during the third trimester and could cause the morning sickness to return.
I've been throwing up almost daily now, and I'm 32 weeks. It started about a week and a half ago.
My first pregnancy I had it from 16weeks till I gave birth. This pregnancy I've just started being sick I'm 36weeks. So I think you can get it at anytime. Mint tea helps and ice cubes. X