Coombs test is a screening test for presence of unwanted antibodies in the blood. It should be negative . It is specifically advised in Rh Negative blood group patients( like yours) . If it comes positive it means you have some kind of antibodies ( allo or auto ) in your body & they will advise you AntiD titre, this should be low. Monitoring by these titres is very important in your case . If Your husband Blood group is Rh positive, then it is very significant.
Next Steps
Husband blood group
Anti D titre
Baby blood group immediately after birth
Anti D injection if indicated