Management and prevention of red cell alloimmunization in pregnancy: a systematic review.

OBJECTIVE: To evaluate the application of new technologies to the management of the red cell alloimmunized pregnancy.

DATA SOURCES: We searched three computerized databases for studies that described treatment or prevention of alloimmunization in pregnancy (MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials [1990 to July 2012]). The text words and MeSH included Rhesus alloimmunization, Rhesus isoimmunization, Rhesus prophylaxis, Rhesus disease, red cell alloimmunization, red cell isoimmunization, and intrauterine transfusion.

METHODS OF STUDY SELECTION: Of the 2,264 studies initially identified, 246 were chosen after limiting the review to those articles published in English and crossreferencing to eliminate duplication.

TABULATION, INTEGRATION, AND RESULTS: Both authors independently reviewed the articles to eliminate publications involving less than six patients. Special emphasis was given to publications that have appeared since 2008.

CONCLUSION: Quantitative polymerase chain reaction can be used instead of serology to more accurately determine the paternal RHD zygosity. In the case of unknown or a heterozygous paternal RHD genotype, new DNA techniques now make it possible to diagnose the fetal blood type through cell-free fetal DNA in maternal plasma. Serial Doppler assessment of the peak systolic velocity in the middle cerebral artery is now the standard to detect fetal anemia and determine the need for the first intrauterine transfusion. Assessment of the peak systolic velocity in the middle cerebral artery can be used to time the second transfusion, but its use to decide when to perform subsequent procedures awaits further study. New data suggest normal neurologic outcome in 94% of cases after intrauterine transfusion, although severe hydrops fetalis may be associated with a higher risk of impairment. Recombinant Rh immune globulin is on the horizon. Cell-free fetal DNA for fetal RHD genotyping may be used in the future to decide which patients should receive antenatal Rh immune globulin.