CD38 and hydrops fetalis: We found that IgD+ CD38dim Activated B cells [OR (95% CI): 1.01 (1.00–1.02)], IgD+ Activated B cells [OR (95% CI): 1.01 (1.00–1.03)], BAFF-R on IgD+ CD24+ [OR (95% CI): 1.02 (1.00–1.04)], BAFF-R on IgD− CD38dim [OR (95% CI): 1.04 (1.00–1.09)], CD19 on IgD+ CD38− unsw mem [OR (95% CI): 1.01 (1.00–1.02)], BAFF-R on IgD− CD38− [OR (95% CI): 1.02 (1.00–1.03)], CD20 on B cell [OR (95% CI): 1.03 (1.00–1.05)], BAFF-R on unsw mem [OR (95% CI): 1.01 (1.00–1.03)] were risk factors for HF.