Comparing the heterozygous form of PAI-1 in RPL and control groups, the results infer a significant increase in the risk of recurrent miscarriage with RPLs under 24 weeks (OR: 1.91; 95% CI: 1.58-2.31), but not in RPLs under 12 weeks (OR: 1.59; 95% CI: 1.20-2.10). The gene discussed is SERPINE1; the disease is spontaneous abortion.