If husband has blood group as B+ and wife has A- then can there be any complications during child birth.?

During pregnancy. Rh Incompatibility is seen when the Father is RH Positive and Mother is RH Negative as in this case. Mother can get sensitized in the first pregnancy. Future pregnancies are then high risk with possible effects on the baby of anemia etc. All pregnant women get checked for their blood type and this risk is avoided by giving Rhogam. I am sure your doctor will keep a close watch on the pregnancy.