CD4 and hydrops fetalis: The results showed that using IVW analysis, an increase in CD39+ CD4+ T-cell count was associated with a decreased risk of HF (OR = 0.96, 95% CI = 0.95-0.98, p = 0.0002), weighted median (OR = 0.96, 95% CI = 0.94-0.98, p = 0.0003), and weighted mode (OR = 0.96, 95% CI = 0.94-0.98, p = 0.022) showed similar positive trends (Fig. 3, Supplementary Tables 9).