So I found out that First Response makes these tests that tests your "fertility". And Im curious to know if I were to take one, would it give me a correct result if I am on birth control? Would I have to have had a full normal cycle before testing? I am on the ring at the moment but Im curious whether I can get pregnant or not if I were to stop the ring. The doctors think I have Endometriosis and I just want to know if I can concieve in the future, by testing my fertility. And has anyone used them and they worked?

Ive screenshotted a picture of the tests I'm talking about.