ABO(H) blood groups and pre-eclampsia. A systematic review and meta-analysis

Area of Science:

• Obstetrics and Gynecology
• Hematology
• Genetics

Background:

• Pre-eclampsia involves placental thrombosis and thrombophilia.
• The ABO(H) blood group system influences von Willebrand factor, a thrombosis risk factor.
• Previous studies on ABO(H) blood groups and pre-eclampsia lack consensus.

Purpose of the Study:

• To systematically review studies investigating the association between ABO(H) blood group and pre-eclampsia syndromes.
• To determine if a consensus exists regarding the link between blood groups and pre-eclampsia.

Main Methods:

• Systematic review of 17 eligible studies.
• Pooled analysis of odds ratios for blood group AB versus others.
• Comparison of non-O blood groups (AA, AB, BB) versus group O.

Main Results:

• No consistent link was found between blood group AB and pre-eclampsia (pooled OR 1.02).
• Comparing non-O groups to group O showed no significant association (pooled OR 1.01), with some heterogeneity.
• No specific study characteristic explained positive associations in a few studies.

Conclusions:

• Available data does not establish a clear association between any ABO(H) blood group and pre-eclampsia.
• An effect limited to individuals with the lowest O(H) antigen expression cannot be excluded.