Since I was going natural, my nurse told me that she wouldn't bother checking me until I felt nauseous since that would signal transition. Well, I never got the nauseous feeling, and when I was screaming at my husband to get the nurse to have me checked, she didn't think I would be at an 8 since I hadn't gotten sick.
I had bad morning sickness at the beginning of pregnancy (lost 15 pounds) and didn't experience nausea during labor. So I didn't have a correlation.