For a study, it was determined that the majority of instances of fetal hemolytic illness needing intrauterine red cell transfusion (IUT) were caused by anti-D and anti-K alloimmunization of red blood cells (RBCs). Only a few research had looked at which hematological variables might predict poor fetal or neonatal outcomes. Preterm delivery, intrauterine fetal death (IUFD), neonatal death (NND), and/or neonatal transfusion were all investigated as potential predictors of unfavorable outcomes. Over the course of 27 years at a quaternary fetal center, researchers analyzed the records of all pregnancies also immunized with anti-K and anti-D that required IUT. They looked at data from 128 pregnancies involving 116 women who had 425 IUTs. The median gestational age (GA) at first IUT for anti-K was substantially lower than for anti-D (243 vs. 287) (P=0004). Women with anti-K required more IUTs than women with anti-D (384 vs. 312 mean IUTs, P=0036), and fetal hemoglobin (Hb) at first IUT was considerably lower (51.0 vs. 70.5 g/l, P=001). 

There was no difference in the mean estimated daily decline in Hb between the two groups. A higher number of IUTs and a slower daily fall in Hb (g/l/day) between the first and second IUTs predicted a longer in utero duration. IUFD/NND was anticipated by an earlier GA at the first IUT and a shorter delay between the first IUT and delivery. The requirement for phototherapy and/or blood product use in the newborn was strongly predicted by earlier GA and lower Hb at the first IUT. Women who had a higher titer required more IUTs in the anti-K group. Furthermore, in both groups, the higher the titer, the earlier the GA was necessary for an IUT. As the frequency of transfusions rose, so did the rate of reduction in fetal Hb between IUTs. Pregnancies with anti-D and anti-K RBC alloimmunization were shown to be at high risk of miscarriage in our current investigation. 

Identifying such individuals helped to guide pregnancy treatment, improve patient counseling, and optimize resource utilization. Prospective studies, in addition to laboratory indicators, could combine these traits to better detect and improve the outcomes of these pregnancies.

Reference:onlinelibrary.wiley.com/doi/10.1111/bjh.17956