Clinical significance of anti‐M in pregnancy and self‐reported ancestry: The <scp>BEST</scp> collaborative study

BACKGROUND: Anti-M antibodies were described as rarely eliciting hemolytic disease of the fetus and newborn (HDFN) in pregnancy. More recent literature, primarily from Asia, reports severe HDFN attributed to maternal anti-M. The objective of this study is to determine if there is a difference in the frequency and/or severity of anti-M HDFN among subjects who self-report as Asian compared to non-Asian. METHODS: Retrospective data were collected from 18 sites. Fetuses/neonates affected by HDFN were categorized as unaffected, mild, moderate, or severe based on clinical management and outcomes. RESULTS: Anti-M was identified in 557 obstetric patients. Among 332 neonates with complete data for analysis, anti-M was detected in isolation during the pregnancies of 210 (63.3%) neonates; 198 (94.3%) were unaffected by HDFN. The overall frequency of HDFN was 6.5% (2/31) in Asian patients and 5.6% (10/179) in non-Asian patients. The frequency of severe HDFN was 6.5% (2/31) among Asian patients and 0.6% (1/179) among non-Asian patients. Among non-Asian patients, eight (4.5%) were mild and one (0.6%) was moderate. Of 63 pregnancies with anti-M and ABO incompatibility, 6 (9.5%) were associated with mild HDFN and 57 (90.5%) were unaffected. Of 49 pregnancies with anti-M and non-ABO antibody(s), 6 (12.2%) were associated with mild HDFN and 43 (87.8%) were unaffected. One case (10.0%) of HDFN (mild) occurred in the presence of anti-M, additional antibody(s), and ABO incompatibility. CONCLUSION: In this study, severe anti-M HDFN was rare in non-Asian subjects. There is a signal that Asian patients are at greater risk for severe anti-M HDFN.

Authors

Institutions

Publication Details

Journal
Transfusion
Published
2026-04-06
DOI
https://doi.org/10.1111/trf.70210
Primary Topic
Hemoglobinopathies and Related Disorders
Type
article
Field-Weighted Citation Impact
0.00
Controls
|||
ALL TIME
JAN
FEB
MAR
APR
MAY
JUN
JUL
AUG
SEP
OCT
article

Clinical significance of anti‐M in pregnancy and self‐reported ancestry: The BEST collaborative study

Judy Ly, Thomas Covello, Jay S. Raval, Jennifer Duncan et al.
Transfusion
Hemoglobinopathies and Related Disorders
article

Clinical significance of anti‐M in pregnancy and self‐reported ancestry: The BEST collaborative study

Judy Ly, Thomas Covello, Jay S. Raval, Jennifer Duncan, Wen Lu, Quentin Eichbaum, Charles Yin, Justin E. Juskewitch, Katie Hands, Rachel Brancamp, Mrigender Virk, Hua Shan, Gisela Marrero‐Rivera, Shelley Chang, Alyssa Ziman, Gwen Clarke, Rida A. Hasan, Sara Bakhtary, Nicholas Au, Laura D. Stephens, Ghazala Radwi, Douglas Morrison, M. T. S. Yan, Kazuhiko Ikeda, Nour AlMozain, The Biomedical Excellence for Safer Transfusion Collaborative, Salwa El Malti, Maha Badawi
article en

Abstract

BACKGROUND: Anti-M antibodies were described as rarely eliciting hemolytic disease of the fetus and newborn (HDFN) in pregnancy. More recent literature, primarily from Asia, reports severe HDFN attributed to maternal anti-M. The objective of this study is to determine if there is a difference in the frequency and/or severity of anti-M HDFN among subjects who self-report as Asian compared to non-Asian. METHODS: Retrospective data were collected from 18 sites. Fetuses/neonates affected by HDFN were categorized as unaffected, mild, moderate, or severe based on clinical management and outcomes. RESULTS: Anti-M was identified in 557 obstetric patients. Among 332 neonates with complete data for analysis, anti-M was detected in isolation during the pregnancies of 210 (63.3%) neonates; 198 (94.3%) were unaffected by HDFN. The overall frequency of HDFN was 6.5% (2/31) in Asian patients and 5.6% (10/179) in non-Asian patients. The frequency of severe HDFN was 6.5% (2/31) among Asian patients and 0.6% (1/179) among non-Asian patients. Among non-Asian patients, eight (4.5%) were mild and one (0.6%) was moderate. Of 63 pregnancies with anti-M and ABO incompatibility, 6 (9.5%) were associated with mild HDFN and 57 (90.5%) were unaffected. Of 49 pregnancies with anti-M and non-ABO antibody(s), 6 (12.2%) were associated with mild HDFN and 43 (87.8%) were unaffected. One case (10.0%) of HDFN (mild) occurred in the presence of anti-M, additional antibody(s), and ABO incompatibility. CONCLUSION: In this study, severe anti-M HDFN was rare in non-Asian subjects. There is a signal that Asian patients are at greater risk for severe anti-M HDFN.

Transfusion
University of Vermont (US), University of Southern California (US), Island Health (CA), Fukushima Medical University (JP), Mayo Clinic (US), University of British Columbia (CA), University of Alberta (CA), University of California, Los Angeles (US), Fraser Health (CA), University of California, San Francisco (US), King Abdulaziz University (SA), Vanderbilt University (US), University of Washington (US), Alberta Hospital Edmonton (CA), King Faisal Specialist Hospital & Research Centre (SA), University of California San Diego (US), Institute for Transfusion Medicine (US), Los Angeles Medical Center (US), Stanford Medicine (US), Scottish National Blood Transfusion Service (GB), Canadian Blood Services (CA), Stanford University (US)
Good health and well-being
Openalex Percentile: Top 21%
Hemoglobinopathies and Related Disorders
DOISourceOpenAlex
AI Navigator

Ask Laika to Summarize, Analyze, and Connect papers live on the map.

Summarize Papers & Methodologies

Extract key findings, datasets, and comparative methods across publications.

Benchmark Rankings & Visual Analytics

Rank top research institutions, authors, funders, topics, and journals by Field-Weighted Citation Impact (FWCI) and paper volume with instant charts.

Connect Distant Disciplines

Bridge topological clusters on the map to find hidden collaborative intersections.