The stress hormone response to intrauterine transfusion Rh alloimmunized fetuses

Objective To evaluate the effect of Rh immunization and intrauterine transf usion on stress hormone levels. Method Umbilical venous samples were obtained immediately prior to transfus ion in 51 anemic fetuses and in a control group of 30 non-anemic fetuses. I n 16 of the anemic fetuses a repeat sample was obtained post-transfusion. S amples were assessed for hematocrit, pH and levels of beta-endorphin, corti sol and adrenacorticotropin. Results The mean initial hematocrit was significantly lower, while the medi an concentrations of beta-endorphin and cortisol were higher in anemic comp ared with non-anemic fetuses at initial sampling. In contrast, fetal adreno corticotropin levels did not differ between the groups. Among anemic fetuse s, both serum beta-endorphin and cortisol levels displayed a strong negativ e correlation with fetal hematocrit (r = -0.46, p = 0.006 and r = -0.54, p < 0.001, respectively). Among anemic fetuses sampled before and after trans fusion, revels of beta-endorphin were significantly lower, while cortisol l evels were significantly higher post-transfusion. Maternal cortisol levels also increased post-transfusion. Conclusion Fetal anemia is associated with increased beta-endorphin and cor tisol levels. While intrauterine transfusion is associated with a decline i n beta-endorphin concentrations, fetal cortisol levels increase following t ransfusion, potentially reflecting transplacental passage of post-transfusi on increases in maternal cortisol.