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Poster Session I Thursday, January 26 • 10:30 AM - 12:00 PM • Octavius Ballroom| Volume 216, ISSUE 1, SUPPLEMENT , S123-S124, January 01, 2017

191: Maternal poly-alloimmunization does not increase the severity of fetal anemia

      Objective

      Maternal poly-alloimmunization has been proposed to increase the risk of fetal anemia. The objective of this study was to compare the severity of fetal anemia in a cohort of pregnant women with single or multiple maternal red blood cell antibodies.

      Study Design

      IRB approval was obtained for a retrospective cohort study of women with alloimmunization from a single institution over a 6-year period (2008-2014). Subjects evaluated by middle cerebral artery Doppler velocimetry studies for elevated antibody titers were included. Clinical data extracted from the medical record included number and type of antibody, time to first Doppler > 1.5 MoM, fetal hematocrit, and clinical outcomes. Descriptive statistics, 2-tailed t-test and hazard analysis were performed using SPSS (Cary, NC) for data analysis.

      Results

      Of 163 subjects, 120 (74%) had a single antibody and 43 (26%) had >1 antibody. Doppler velocimetry >1.5MoM was present in 19 subjects (16%) with a single antibody and 14 subjects (33%) with multiple antibodies (p=0.04). Anti-D was the only antibody more frequently associated with elevated Doppler values (39% vs 20%; p=0.04). Hazard analysis revealed a median survival time to Doppler velocimetry >1.5MoM of 34.7 (95% CI 30.9 - 38.5) weeks with a single antibody and 31.6 (95% CI 29.8 - 33.3) weeks with multiple antibodies (p=0.15). The median survival time was 31.1 weeks (95% CI 29.5 - 32.8) in the presence of Anti-D antibodies, compared to 35.4 weeks (95% CI 29.1 - 41.8) with all other antibodies (p=0.04). The survival time for subjects poly-alloimmunized with anti-D (31.6 weeks; 95% CI 24.8 - 38.3) was comparable to subjects poly-alloimmunized without anti-D (31.6 weeks; 95% CI 28.4 - 34.7) (p=0.77). Fetal hematocrit measured during percutaneous umbilical vein sampling did not differ between subjects with a single antibody or multiple antibodies (21.3+/-10.3 vs. 17.7+/-9.6; p=0.52).

      Conclusion

      Poly-alloimmunization and Anti-D are risk factors for elevated Doppler velocimetry. However, multiple antibodies do not appear to increase the severity of fetal anemia.