Well, many cysters are estrogen-dominant, meaning they have higher levels of estrogen in relation to progesterone. Lower progesterone = lower body temps. Met regulates insulin levels, which in turn helps to regulate the female hormones. So for some, that could mean an increase in progesterone as the hormones are balancing out, which in turn would cause a rise in BBT's. The thyroid gland, which regulates body temp, needs a sufficient amount of progesterone to function optimally (excess estrogen can inhibit thyroid function), so balancing out the progesterone/estrogen ratio can have an indirect effect on thyroid function and body temps.
Just remember that it can take months for the balancing to take place, and cycles can be a bit whacky at first on Met.
Linda
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dx pcos 1984, type II diabetes 2001, also hypertension
Met 2000mg since 2001, started Glucophage XR 4/22/04, then switched to Met ER 6/04; also: multi, Vit. C, Vit. E, B12/folic acid combo, fish oil & borage oil combo, garlic capsules, cinnamon, Vitex, calcium with magnesium/zinc, biotin, CoQ10, selenium,iron
Other meds: Verapamil and Altace(for blood pressure)
Started laser hair removal 7/29/03, completed 3/04 (it works!)
UAE for fibroid 3/24/03 and 3/16/04 | 
metformin and bbt 
My BBT has been insanely high from about CD1 through to now (CD 11). I started metformin on 2 days before CD1. I was concerned about the high temps, but have found a few sources that say this is normal. I'd really just like even temps and to ovulate 
