ICT is Indirect Coomb's Test, performed in pregnancy
to detect antibodies
, that may cause harm to the baby. It is also done prior to blood transfusion
. It has been perhaps advised in your case as both of you have Rh incompatibility and your son is Rh positive. This results in development of antibodies in the mother's blood which can pass through the placenta and harm the next child, if the child is Rh positive. If ICT is positive, your wife may need to take anti-Rh antibody injections to nullify the effects. Please get further suggestions from your doctor. Good luck.