Am insulin resistant & have PCOS. Had my DD through IVF & I was on metformin for the entire first trimester (can't remember dose as it was over 6 years ago now) but had been on 2500 mg/daily at the most. Both FS & OB were happy for me to stay on it 1st trimester & then go cold turkey. After that pregnancy was able to reduce to 500mg/daily & am currently trying for number 2 (again!) it hasn't even been a consideration for my FS this time. Good luck!