hi here is a site that may help. I use it to help me figure out approximately how many months I am.
http://www.****.com/pregnancylength.html
Yay i am 2 days away from my last trimester an 7 months.
I Google a pregnancy calendar to help me convert weeks to months and it says 27wks is the beginning of your third trimester and also the beginning of your 7th month.....its so confusing lol
My doctor told me end of 27 weeks, start of 28 weeks, and my tracker on here switched to 3rd trimester at 28 weeks! :)