ABO blood group distribution and infertility risk in Southern China: a retrospective analysis of the Ganzhou Region.

OBJECTIVE

To investigate the distribution of ABO blood groups among infertile couples in Southern China (Ganzhou region) and to explore the association between blood types and male reproductive parameters.

METHODS

This single-center retrospective study analyzed data from 696 infertile couples who sought treatment at a tertiary reproductive medicine center in Southern China between 2016 and 2024. ABO blood group distributions in infertile men and women were compared with those of a large-scale reference population from Southern China (n ≈ 14.41 million). Chi-square tests, Cramér's V effect size, and the observed-to-expected ratio (O/E) were used to evaluate associations between couple blood type combinations and semen parameters, including sperm concentration, total sperm count, progressive motility, and normal morphology.

RESULTS

Blood group O was significantly overrepresented in infertile men (39.51% vs. 34.21%, P = 0.008) and women (41.67% vs. 34.19%, P < 0.001), whereas blood group AB was underrepresented (men: 6.18% vs. 8.91%, P = 0.008; women: 6.47% vs. 8.91%, P = 0.008). The O/O couple blood type combination showed a significantly higher prevalence among infertile couples (16.81% vs. 11.70%, O/E = 1.44, P < 0.001), while combinations involving A/B and B/AB occurred less frequently (O/E = 0.57-0.78, P < 0.05). Male blood type was associated with sperm normal morphology (O < A < B < AB, P = 0.02), but not with sperm concentration or progressive motility.

CONCLUSION

Blood group O-particularly the O/O couple combination-may be associated with an increased risk of infertility, whereas combinations involving B or AB blood groups may confer a potential protective effect. The ABO blood group type may influence male fertility, partly through its association with sperm morphology. These findings provide region-specific evidence and underscore the need for large-scale, multi-center studies to further validate the observed associations.