Forgot to mention a couple things...first, you can use saline solution daily to help keep your nasal cavities healthy, which should help. Second, if you get lots of nosebleeds, you might mention it to your doctor and have him check your blood pressure, just to be sure.
Go team hormones! LOL.
Nosebleeds are very common during pregnancy for two reasons. Number one, your blood volume increases by something like 40% while your pregnant, which can cause more pressure on the blood vessles in your nose and number two, your nasal cavity is more prone to swelling and dryness due to allergies and minor infections during pregnancy, which can both cause nosebleeds. I haven't had any myself, though I have had a little more "stuffyness" than normal.
Take care!