hey there.
congratulations on your pregnancy. please be safe about the gum bleeding tho. hep b doesn't cause it, but please be safe and clean with the blood. hep b can survive on surfaces for 10 days and can still be infective. so, if your spouse or children are hep b negative i'd be very very careful with any products/surfaces that might contain blood.
Pregnancy increases your blood volume and can cause gums to bleed when you brush.