Why is there no problem with the pregnancy of an Rh-negative mother carrying an Rh-positive child if the mother had never been exposed to Rh previously, when a second pregnancy with another Rh-positive child leads to a miscarriage?

MCQs on the immune system, including innate and adaptive immunity, the cells involved in each of process of the immune system and their role in the immune response, and how antibodies are used to confer immunity for future potential exposures.