Before reading Brightlight's response, I was about to say that I didn't think you could compare blood and saliva levels? Mine, like Hurdity's, were blood levels, measured in pmol which seems to be the NHS standard (?). I was told that my reading of 40, on day 5 of my period, was just below the lower level of tolerance - which seems to be in line with Hurdity's link.
I have been thinking a lot recently about the symptoms of both high and low estrogen levels. One of the reasons I moved from HRT to Qlaira was that I felt I was having fluctuations, so at times, I was having too much estrogen (which caused, I thought, a jittery feeling and nausea/headaches). Now I have been on Qlaira for 5 weeks - which has a much higher level of estorgen, albeit a HRT style estrogen - those symptoms have totally disappeared. The biggest difference is the psychological one (still getting weird tingling occasionally). The lesson I've learned? That in our 40s, it appears, some of us do need (and can tolerate) a much higher level of estrogen than someone 10 or 20 years older. It was the anxiety stopping me from 'risking it'. Catch 22!
The added benefit of Qlaira is that GPs who won't prescribe HRT for peri penopausal women seem to still prescribe this as it's classified as a contraceptive, albeit a low dose, 4 phase, more unusual one.
B x
NB GPs are aware that Qlaira is more expensive than most other pills so sometimes won't mention it. However, if they will prescribe it, it's free.