Okay, I had to look this up. Yasmin has 30 micrograms of estrogen
YAZ has 20 micrograms of estrogen
That is 10 micrograms difference, true, only 0.1 mg (milligrams, not micrograms). But still a lot less. Consider that the patch, which has been causing blood clots & stroke problems gallore, is 75 micrograms--"only" 0.4 mg more than Yasmin & 0.3 more than Desogen.
In addition, on YAZ, blood concentration of estrogens ranged from 32.8-45 pg/mL by the end of one cycle, whereas Yasmin estrogen was 87-91 pg/mL.
A little estrogen goes a longgg way!
FYI, the Ring releases daily 15 micrograms estrogen & .12 mg progestin (etonogestrel, a metabolite--byproduct--of desogestrel, like the progestin in desogen more or less). Blood concentrations were incredibly low, at ~17 pg/mL estrogen after one cycle. If spiro doesn't work for you, and estrogen drives you nuts, or you hate taking pills, that might be an option.
For me, if I ever go on bcp again, I refuse anything with estrogen over 20-something. I already know the end result--me going looney & fat.
Both YAZ/Yasmin pills have 3 mg drospirenone.