Through re‐sequencing and genotyping, we finally identified a common variant in the 3′UTR of PIK3CG strongly associated with the prognosis of HF in two‐stage population: adjusted p = 0.007, hazard ratio = 0.56 (0.36–0.85) in the first cohort and adjusted p = 0.024, hazard ratio = 0.39 (0.17–0.88) in the replicated cohort. The gene discussed is PIK3CG; the disease is hydrops fetalis.