Flax A few months ago I was asking exactly the same question when I was on conti utrogestan. Hurdity may remember. (Thanks for all your help hurdity.)
Now that might have been because my eastrogen was low so there wasnt enough to counter the side effects . As hurdity says.
I'm struggeling to get my eastrogen up so
I went onto a 12 day cycle and it has helped me to identify how many days it takes befor the fatigue, drowsiness kicks in. For me it is day 9/10 but you may find you can get to 12, lots of ladies seem to.
One thing I can now say for certain is that it triggers my headaches and migraine.
When I took it conti I had it the first 2 weeks but it went away after that. On a cycle it's happening each month throughout the progesterone part.
I should probably point out that migraine has not come out of the blue for me. They got worse in my 30s and neurologist thought they were hormone sensitive. So I think it's important to say I dont believe utrogestan has caused me to develop migraine, more that it has triggered a condition I was already prone to.
I've been reading up about migraine and HRT and it's thought that fluctuation is a trigger iand a conti regime is considered preferable.
So I now know I need to look at an alternative conti regime. But my point is I only found all this out by trying the cycle. It has been a good exercise for me and helped in beginning to untangle what can feel like a very confusing web.
Hope this may help you a bit.
Good luck.
I cant say whether