Do not repeat prenatal titrations for mothers with clinically significant antibodies (e.g. RhD, K) if prediction of fetal cognate antigen typing is feasible and is deemed to be negative.

Testing of a paternal sample and finding a negative antigen status (when paternity is assured) and/or non-invasive prenatal determination of the fetal genotype from maternal plasma with prediction of a negative antigen status confirm that the fetus is not at risk for hemolytic disease of the fetus and newborn and that ongoing pregnancy monitoring is unnecessary.
For more information:

de Haas et al. Haemolytic Disease of the fetus and newborn. Vox Sang. 2015 Aug;109(2):99–113. PMID: 25899660.

Scheffer et al. Noninvasive fetal blood group genotyping of rhesus D, c, E and of K in alloimmunised pregnant women: evaluation of a 7-year clinical experience. BJOG. 2011 Oct;118(11):1340–8. PMID: 21668766.