432 To determine the rate of decline of fetal hemoglobin following an intrauterine blood transfusion

Abstract

Listen

Translate article

Hemolytic disease of the fetus and newborn (HDFN) is characterized by fetal anemia, secondary to maternal alloantibody-mediated fetal erythrocyte destruction. While RhD immunoprophylaxis has reduced the requirement for intrauterine blood transfusion (IUT), this procedure remains the cornerstone of treatment for severe fetal anemia. The objective of this study was to calculate the rate of daily decline in fetal haemoglobin (FHb) following IUT for fetal anemia. This was a retrospective review of all patients who underwent IUT for fetal anemia at the National Maternity Hospital, Dublin, a tertiary referral centre, over a 10-year period (2011-2020). Data was analysed and the rate of daily decline was calculated for those after one, two and three IUT procedures. Results are presented in Table 1. A total of 98 intrauterine blood transfusions were performed in 46 fetuses, of which 31/98 (67%) and 16/98 (34.7%) required a second and a third IUT, respectively. The median gestational age (GA) at first IUT was 29+1 weeks (range 17+2-34+5 weeks), and the median GA at second IUT was 29+2 weeks (range: 22+0-34+4 weeks). The median rate of decline in FHb between first and second IUT was 0.442g/dl/day (range: 0.12-1.03g/dl/day). The median GA for a third IUT was 32 weeks (range: 26+2-34+5 weeks). The rate of decline in FHb level between the second and third IUT was 0.291g/dl/day (range: 0.16-0.43g/dl/day). Only 5/98 (10.8%) of cases required a fourth IUT at a median GA of 31+4 weeks (range 30+0-34+0 weeks), with a rate of decline of 0.26g/dl/day (range 0.217-0.317g/dl/day). No fetal or maternal mortality was observed in our series. This study provides guidance as to the rate of FHb decline post a varying number of IUT procedures, and observed a reducing rate of decline following successive transfusions. It also highlights the significant range of decline that exists between patients. Careful fetal monitoring between transfusions must remain a vital part of the management of HDFN.