I don't know a great deal about PCOS but from my understanding it can cause major hormonal acne? My situation was actually the opposite of yours. I had beautiful glowing skin and amazing hair throughout my pregnancy and 3 months after more than half my hair fell out and I got bad cystic acne all over my face and body, which nothing would help. So I had to try to focus on being a new mom (of twins) while feeling so extremely bad about myself. I also took showers in the dark and tried not to look at myself in the mirror. Since having them 2 and a half years ago I've learned that skin is only part of what you sacrifice. I don't know what's worse, skin or sanity. No sleep sure takes a toll...
In my search to fix it I've read a LOT of women's stories and have noticed there are pretty much two pregnancy/acne groups; those who have amazing skin during pregnancy and then get hit hard afterwards (like me) and then those who all of a sudden get bad acne during pregnancy, but luckily for them it clears up right after or within a couple months of giving birth. My bet would be you won't need anything like spiro, which I personally wouldn't want to risk anyway. Huge chance it will clear right up afterwards. Right now the very worst thing you can do for your acne is worry and stress, which will help put your hormones in overdrive. Stress is also bad for your baby. The best thing you can do right now is make sure you are eating a really healthy diet with lots of veggies, no junk food, no sugar, minimal processed foods, take a prenatal vitamin and make sure you get enough protein and that your iron levels are good.
Also, I also could never use Cerave cleansers. It made everything SO much worse. Sulfur is safe to use during pregnancy and is really effective for acne. Here is the sulfur soap I use, though it's only 3% sulfur and there are much stronger ones, I found it to be strong enough: http://www.amazon.com/Thylox-Medicated-Soap-Grandpa-Company/dp/B000I7S8XG/ref=sr_1_2_a_it?ie=UTF8&qid=1460487460&sr=8-2&keywords=thylox+soap
Clearasil's adult tinted acne cream has also been a lifesaver. The internet seems to think it's safe to use during pregnancy but I would check with a doctor because along with sulfur it also has2% of resorcinol, which I'm not sure about: http://www.amazon.com/Clearasil-Daily-Clear-Tinted-Treatment/dp/B000NNL7FG/ref=sr_1_1_a_it?ie=UTF8&qid=1460487629&sr=8-1&keywords=clearasil+tinted+adult
Others that are good:
~ http://www.amazon.com/Dr-Bronners-Pure-Castile-All-One-Unscented/dp/B001F0RA8E/ref=sr_1_3_a_it?ie=UTF8&qid=1460487917&sr=8-3&keywords=dr+bronners+bar+soap This is actually my favorite. I use the tea tree one but the unscented one is going to be better for pregnancy. Most stores carry this, especially health food stores. Not even sure why castile soap clears acne, but it works well and Dr Bronners is the best.
~ http://www.amazon.com/Nubian-Heritage-African-Black-Ounce/dp/B000XLWZGI/ref=sr_1_7_s_it?s=beauty&ie=UTF8&qid=1460488009&sr=1-7&keywords=african+black+soap ~http://www.amazon.com/Aztec-Secret-Indian-Healing-Cleansing/dp/B0014P8L9W/ref=sr_1_1_s_it?s=beauty&ie=UTF8&qid=1460488278&sr=1-1&keywords=aztec+indian+healing+clay (amazing stuff!!!)
Anyway. Hang in there. Baby will make it all worth it. People won't be judging your acne while your pregnant or even afterwards, people get that hormones are like this. Try not to STRESS...
PS. there's also places online like circle of moms which helped me feel not-so-alone with all my pregnancy problems. Other moms will give you advice and support and know what you are going through: ~ http://www.circleofmoms.com/moms-under-30-1/did-your-skin-suffer-during-pregnancy-525527?trk=desktop_search ~ http://www.circleofmoms.com/search/pcos