In fetuses without hydrops that are at risk because of maternal red-cell alloimmunization, moderate and severe anemia can be detected noninvasively by Doppler ultrasonography on the basis of an increase in the peak velocity of systolic blood flow in the middle cerebral artery.

We investigated whether Doppler measurement of the fetal middle cerebral artery peak systolic velocity can be used to detect fetal anemia in pregnancies complicated by maternal blood group immunization. We first studied normal values for the middle cerebral artery peak systolic velocity in 135 fetuses (Group A), and also in 23 fetuses at risk for anemia who underwent 56 cordocenteses to assess the fetal hematocrit (Group B). A test to detect fetal anemia, based on the middle cerebral artery peak systolic velocity, was developed by using the data of the fetuses of Group A and Group B. Successively, the middle cerebral artery peak systolic velocity was prospectively determined in 16 fetuses at risk for anemia who underwent 42 cordocenteses (Group C) to assess the test developed, in a multicenter prospective fashion, by using the data of Group A and Group B. In the normal fetuses an exponential model expressed the increase of the middle cerebral artery peak systolic velocity values with advancing gestation. By using the data of the fetuses of Group A and Group B, four zones of anemia risk were identified. In Group C, none of the anemic fetuses had the middle cerebral artery peak velocity below the normal mean value, whereas all of the anemic fetuses had the peak velocity above the normal mean. The middle cerebral artery blood velocity increases with advancing gestation and is a non-invasive method of detecting anemia in pregnancies complicated by maternal blood group immunization.

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Developmental defects in neutrophil function, including diminished expression of plasma membrane receptors, may play an important role in the susceptibility Human neonates, especially those born prematurely, are highly of the newborn infant to infection. We used n~onoclonal susceptible to serious infections with bacterial, viral, and fungal antibodies and flow cytometry to study the expression of pathogens, including some that do not ordinarily cause systemic complement receptor type one (CRl), complement receptor disease in immunocompetent older children or adults (I). In type three (CR3), and Fc, receptor type three (FCRIII) On concert with developmental deficiencies in other parts of the neutro~hils from six fetuses with Rh disease, 10 preterm immune system, of neutrophil function play an infants, nine term infants, and nine adults. Expression of important role in the enhanced susceptibility of newborn infants the complement receptors on unstimulated cells was similar to infection (2). Study of fetal neutrophils, made possible by in for all groups, but significant differences in complement utero sampling of umbilical cord blood (3), may provide new receptor expression were observed after stimulation with insight into the interplay of developmental and environmental N-formyl-methionyl-leucyl-phenylalanine (FMLP). Fetal, effects on neonatal neutrophil function. preterm, and term infant neutrophils expressed less CR3 Neutrophils from newborn infants have well-recognized de-~ than FMLP-stimulated neutro~hils of adults 161 f 2, 48 fects in adherence-related functions, including an impaired abil-, f 4, and 66 f 4% (mean f SEM) of the mean for adults, ity to increase adherence after stimulation with chemotactic P < 0.051-FMLP-stimulated CRl expression for these factors (4). Although the mechanisms responsible for this defect groups was 61 f 6773 2 6, and 91 2 9% of the adult mean are incompletely understood, abnormal upregulation of plasma (p < 0.05, fetal versus term infant and adult). Expression membrane expression of CR3 may be an important factor (5). of both CR3 and CR1 increased with ~ostconce~tional age Neutrophils from term infants stimulated with chemotactic facin the infants (# = 0-49, P < 0.001 for CR3; 3 = 0.231 P tors such as FMLP express significantly less CR3 than neutro