I cannot get an epidural or a spinal block, will they automatically use general anesthesia for a c-section?

Yeah, it's the same medications used in different places. Are you sure it's a true allergy? You've been tested by an allergist? I say that because we see a lot of people who claim to be "allergic to Novocaine" when what they actually experienced was a reaction to the epinephrine that is used with local anesthetics. True allergies to local anesthetics are usually to the esters, and very very rarely to the amides, which are what we use in neuraxial blocks. It's worth it to be tested and be sure, because spinals are MUCH safer for you and the baby. We do general anesthetics when we have to, and we usually have no problems, but the risks of serious problems are about 10x that of non-pregnant patients. Oh and to answer your question, there are no alternatives if local anesthetic medications cannot be used. congrats on the baby :)