A condition arises when there is a blood type incompatibility between a Rh-negative mother and her Rh-positive baby, leading to the mother’s immune system launching an attack against the unborn child. This sensitization typically occurs during the delivery of the first pregnancy, where the mother’s immune system becomes responsive to the Rh-positive blood of the baby. Consequently, subsequent pregnancies may be at risk as the mother’s immune system can potentially cause severe illness or even fatality in those babies.