Month1 - week1-4
Month2 - week5-8
Month3 - week9-13
Month4 - week14-17
Month5 - week18-21
Month6 - week22-26
Month7 - week27-30
Month8 - week31-35
Month9 - week36-40
Thanks so very much @5Nov
It means you are in your eighth month... but technically you have not been pregnant for a full 8 months until week 35!