The main risks for newborn infants include low blood pressure and low blood sugar. The use of any drugs during labor should be discussed carefully with your physician to evaluate the possible benefits and risks both to yourself and to your baby.
You might want to consider inquiring at your planned birth hospital for supportive services available to expectant mothers. You might be able to deal with anxiety using non-medication techniques. Examples include specialized birthing rooms, biofeedback, supportive personnel such as a "doula", and specialized counseling.
Thanks for answering me. I have tried discussing it with my obstetrician but he doesn't want to help me research this, which is why I'm asking around on the Net! It seems like a topic that doesn't quite fit into pure obstetrics or cardiology or general studies on anxiety, so it's difficult to find anyone that's given it much consideration. Any ideas where I could ask next?