A.P.
Hi, M.!
Fist of all, kudos to you for nursing on an extended basis! So few moms are willing to do that today. That is so wonderful & I congratulate you on that!!!
According to Dr. Hale's book "Medications & Mother's Milk" (which is a medical reference book for drugs & how safe/unsafe they are for use during pregnancy & lactation) Seasonale is listed as an L2, which is really very safe. L1 is the safest (multivitamins, tylenol, etc...) & L2 is just below that, of course. Just for a frame of reference, an L3 would be safe to take as long as the bennefits of nursing outweighed any possible (and unlikely) "risks" of taking the drug, L4 is possibly unsafe & L5 is unsafe.
It does list on another page that Seasonale specifically, is an L3, mostly for the estrogen content (can reduce your supply). There have been no other reported pediatric concerns (other than a possible reduced supply of milk) reported though.
Headache is reported as a side effect for adults though.--Just FYI.
Have you looked into a low-dose estrogen pill at all? Just a thought!
Hope that helps some!
A.