Yes, unfortunately. It's hormones. I've had swollen bleeding gums every time I was prego. The trick so they don't get really bad is you HAVE to floss, 3/4 times day & brush your teeth 3/4 times a day also. Otherwise the swelling & bleeding will get really bad.
Your dentists office can order you this special gum too! Mine was trying to push it on me but my gums are fine.
I had really bad swollen gums in my 2nd trimester and I had to gargle water and salt around 3 times a day. The dentist was such a waste of time he said everything was perfectly fine and just to continue what I was doing. I also flossed and used mouth wash. It really helped!