Chapter 221 Rh Incompatibility
INTRODUCTION
Description: Isoimmunization to any fetal blood group not possessed by the mother is possible. The most common example is the Rh (D) factor. What was once a common cause for intrauterine fetal death has largely been eradicated by prophylactic administration of immune globulin to those at risk.
DIAGNOSTIC APPROACH
Workup and Evaluation
Laboratory: Serum antibody titers (at first visit, 20 weeks, and approximately every 4 weeks thereafter), testing of baby’s father’s antibody status. Emerging data suggest that it may be possible to determine the Rh status of the fetus directly from fetal cells circulating in maternal blood.
Imaging: Ultrasonography is useful to establish gestational age and monitor amniotic fluid volume and fetal growth. Some studies have assessed the ability of ultrasonography to monitor the degree of fetal anemia, but this technique has not gained wide usage.
