Progesterone is the big enemy of insulin. The dip of progesterone during menstruation is why many women need a basal reduction at that time. It then ramps up prior to ovulation, decreases a bit, and then climbs and decreases again for the second half of the cycle.
I said in a different post elsewhere on FUD that I always have issues on Day 23. Look at the chart. I’m apparently fairly textbook there.
Something I can’t remember/don’t know…is I don’t remember how Estrogen impacts insulin resistance. Based on the big spike of insulin resistance during ovulation for many women (myself included), I tend to think both estrogen and progesterone are insulin resistant. (Further: During pregnancy, your insulin needs go down initially and then climb steadily…and I believe that is due to the initial estrogen dip. I could be wrong there. Literature on these topics isn’t exactly the easiest to find…nor is any of it terribly concrete. Mayo Clinic’s article about diabetes and menopause just says, " The hormones estrogen and progesterone affect how your cells respond to insulin. After menopause, changes in your hormone levels can trigger fluctuations in your blood sugar level." Yes. Thank you, Mayo Clinic. That was very insightful.)
So yeah, if the ONLY time I had to worry about changing basal rates was during menstruation, I’d be the best damn diabetic you ever met. But that is a woeful misconception in the medical community (and the diabetic public) and it is, IMO, a disservice that there is not more actual information out there. Everyone tells us, “This might affect your blood sugar”, but no one says anything more than that. And I’d love to be wrong about that. I’d love that so much.