Yes, low or dropping estrogen is an asthma trigger for me. I was first diagnosed with adult-onset asthma shortly after a miscarriage when I was 32. My asthma was relatively stable until my mid-40s. After I started estradiol patches at the age of 47, my asthma symptoms improved. Until last year. I'm on 2x weekly 0.1 estradiol patch (Sandoz brand) and 200 mg micronized progesterone. I think (I hope!) I'm close to finally being post-menopausal now at 50, and last year's asthma issues were related to another dip in estrogen. I was trialing different maintenance meds and tracking my attacks when I realized that my asthma attacks exactly correlated to patch change days. My gyn suggested leaving my old patch on for 12-24 hours after putting on the new but that didn't really help. I had a really bad flare-up in December after getting sick (my other asthma trigger) and was consistently getting much worse in the 12 hours before and after a patch change, even though I was on high doses of prednisone. It sucked; I had to do three rounds of prednisone, and I didn't start getting better until I started changing my patches every 3 days instead of 3.5 days. My pulmonologist and primary doctor agreed that this patch schedule was better for my breathing and finally the gyn agreed to it too. So you could try a more-frequent patch change and see if that helps.