I was thinking abut this last night and I do remember there is a reason why they do not reccommend metformin in the last trimester. I can't remember where I found this out...was in a journal somewhere but to the best of memory here goes: metformin is a hypoglycaemic agent/drug that crosses the placenta and therefore can also cause the babies blood sugar to drop causing hypos in utero. This has the potential to cause fetal distress and even fetal death. Insulin does not cross the placenta and therefore cannot affect the babies sugar levels.......If you want I can ask my endo about it, he would be able to confirm this. I don't want to scare you off it but just thought I should share what I know in case you hadnt heard that as it has been nagging at me for some reason. Also remember metformin will only be effective to a certain point. As you have symptoms this early in the pregnancy and havent yet hit the period of major insulin resistance from about 24 weeks, you may find that you will probably need to cross over to insulin at some point anyways. anyhow Best of Luck and if you have any technical D questions feel free to pm me.