See also: Routine prenatal care
Risk is that mother may form antibodies to Rh antigen on fetus' RBCs, which cross the placenta and destroy fetal RBCs potentially resulting in severe anemia (erythroblastosis fetalis), high output cardiac failure, hydrops fetalis, and possibly fetal demise.
Prenatal cerebral blood flow via ultrasound is one way to ascertain fetal cardiac output.
Provide RhD blood typing and antibody testing:
Give another dose if not alloimmunized and has a procedure or bleeding event (spontaneous abortion, threatened abortion > 12 weeks gestation unless significant bleeding, termination of pregnancy, ectopic pregnancy, amniocentesis, chorionic villus sampling, fetal blood sampling, D&C for hydatidiform mole, blunt force trauma, bleeding to to placenta previa or abruption, external cephalic version, intrauterine fetal death) (and don't wait for antibody testing results if not available):
After delivery of an Rh-positive child (determined by cord blood) to an Rh-negative mother, additional screening should be done to determine if additional RhD immunoglobulin is required (Kleihauer–Betke Test or Rosette Test
If a mother is not sensitized (or has a VERY weak titer), anti-D immunoglobulin is indicated.
If a mother is already sensitized (antibody titers >=1:6), administration of RhoGAM is not helpful and close fetal monitoring for hemolytic disease is required.
The critical antibody titers that put a fetus at risk for hemolytic disease are usually between 1:8 and 1:32 (1:16 is frequently cited as critical).