As far as I know PCOS is genetic. For PCOS, you have to have several symptoms to qualify and it’s not curable. There can be some hormonal delays with getting off and on birth control.

From my understanding and some little research, there isn't a link to BC causing PCOS. For some, BC can help manage the symptoms of PCOS, but that's about as far as it goes. PCOS can cause some liver issues and halt menses. This isn't always true for everyone and isn't always right from menarche. I had regular periods for years and once extreme stressors set in thats when I got symptoms. This may also be the case for you, since pregnancy is a great stress on your body. I'm really sorry you're going through this, I hope things get better ❤️

Yes BC withdrawal, which peak 6mo - 1yr after stopping BC, can cause PCOS. Also some of the progestins in BC are actually androgenic and can cause PCOS. So in short yes definitely.