Fetomaternal Hemorrhage: Evaluation of Recurrence Within a Large Integrated Health Care System

• Published in: American journal of obstetrics and gynecology
• Main Authors: Boller, Marie J, Moore, Gaea S, Hung, Yun-Yi, Ritterman Weintraub, Miranda L, Schauer, Galen M
• Format: Journal Article
• Language: English
• Published: United States 04.05.2021
• Subjects: Fetal anemia; Intrauterine fetal demise; Flow cytometry for fetal hemoglobin; IUFD; Kleihauer Betke; Fetomaternal hemorrhage; Neonatal anemia
• ISSN: 1097-6868

Fetomaternal hemorrhage is associated with severe fetal morbidity and mortality. The recurrence risk of fetomaternal hemorrhage is unknown. We sought to establish the recurrence rate of fetomaternal hemorrhage in a large integrated healthcare system over a 10-year period. In this retrospective study within the Kaiser Permanente Northern California medical system, cases of fetomaternal hemorrhage were defined by either an elevated fetal hemoglobin flow cytometry value with concerning pregnancy outcome (preterm delivery, perinatal demise, neonatal anemia, or transfusion in the first two days of life), or perinatal demise with autopsy findings suggestive of fetomaternal hemorrhage. Subsequent pregnancy outcomes were reviewed for features of recurrence. Within the 2008-2018 birth cohort of 375,864 pregnancies, flow cytometry testing for fetal hemoglobin was performed on 20,582 pregnancies. We identified 340 cases of fetomaternal hemorrhage (approximately 1/1100 births). Within the cohort of 340 affected pregnancies, 80 (23.5%) had a perinatal loss and 50 (14.7%) had a neonate requiring transfusion. The affected patients had 225 subsequent pregnancies, of which 210 were included in the analysis. Of these, 174 (82.9%) advanced beyond the threshold of viability and were delivered within our health care system. There was one case of recurrent fetomaternal hemorrhage identified. The case of recurrence involved a spontaneous preterm delivery of an infant who was noted to have an elevated reticulocyte count but was clinically well. Within our large integrated health care system, approximately 1/1100 pregnancies were affected by fetomaternal hemorrhage within a 10-year period, comparable to prior studies. We identified one case of recurrence, yielding a recurrence rate of 0.5%. This infant did not have features of clinically significant fetomaternal hemorrhage. This information can inform counseling of patients with affected pregnancies.