My husband and I are both B negative.I am pregnant.Is there any risk for birth defects?

The risks of birth defects depend on so much more than just simply blood type. This is really something you need to discuss with your dr. as it will vary from couple to couple. Your dr should know about both yours and your husband's medical history, and both of your families medical histories. Even then, some birth defects can't be predicted. At least not yet.

Blood type has nothing to do with birth defects. It's genetics that actually plays that role.

With both of you being Rh negative, there is little chance for anything going wrong. HOWEVER, you doctor will want to give you a Rhogam shot at approximately 28 weeks gestation, then again within 72 hours after birth if the baby does end up with a Rh positive blood type.