I've often wondered this too.
Even before peri menopause, whilst I was suffering since the birth of my last baby, with monthly PMS.
In particular because I had sacroiliac joint dysfunction and then a big injury to this joint in my last pregnancy
![Sad :(](https://www.menopausematters.co.uk/forum/Smileys/extended/sad.gif)
and it flares up every month on the run up to a period because the same hormones released in pregnancy to relax the pelvic girdle in readiness for birth, are released in 2nd half of menstrual cycle, causing me great pain.
I still get it now, 13 years later.
I'd have loved to have had the opportunity to have spoken to a hormone specialist, I think it would have been useful.