honeybun - it is likely that your daughter is unfortunately affected by the synthetic oestrogens in the combined pill and that bio-identical estradiol would not necessarily affect her in the same way, so there is still hope for her many years in the future when she will be thinking about HRT. I'm not sure whether any BCP contain estradiol?
Dancinggirl - progesterone is unstable as a molecule so could not be put in a ring as I understand, and dydrogesterone is closely related to progesterone so it may be true for this progestogen too? Dydrogesterone used to be available separately as Duphaston but was withdrawn commercially a few years ago - I think it is still available in some countries. I think there was even one HRT which had separate estradiol and dydrogesterone tablets - but of course that is now available as Femoston in a combined tablet. Not much help for those who want to try a different progesterone from Utrogestan, but one of the least androgenic ones!
I also looked up one of the papers which talks about different routes of administration for HRT and there has been research done on vaginal rings containing higher doses of estradiol than the Estring - which gave favourable systemic concentrations, so it could be made available. Unfortunately we are at the mercy of the big Pharmas in all of this and it is extremely frustrating that perfectly good products are withdrawn from the market, or not developed for commercial use, because of markets and profits. I presume also there have to be trials as well to look into long term effects etc which are costly. Not good news for menopausal women though

Hurdity x