Counting from 2 weeks before O, it was 42 weeks (went into labor at 41w5d, had him just after midnight 28 hours later). So glad I knew my O date and wasn't going off LMP or I'd be 42w5d and really impatient. As it was I did drink 1oz of castor oil.
I guess I did mean to add two weeks so you're counting as if from LMP. Not sure if that was clear. So like, if you were actually only pregnant for 37 weeks from ovulation, you would respond, "39 weeks"
I was definitely irregular, due to my petite size, it took us three months of actively trying to get pregnant, but I seemed to ovulate the same time no mater what, which was almost every 35 days and she came the day I knew she would :)