Quality control process of the genes
| Gene | SNP | Detection rate <90% | MAF <0.05 | HWE <0.05 | Valid SNP |
| VEGFA | 28 | 5 | 0 | 0 | 23 |
| VEGFB | 7 | 0 | 1 | 1 (repeat with detection rate <90%, rs199850719) | 6 |
| KDR | 20 | 4 | 2 (1 repeat with detection rate <90%, rs199850719） | 2 | 13 |
| FLT-1 | 20 | 0 | 3 | 0 | 17 |
| IGF-1 | 13 | 1 | 0 | 0 | 12 |
| IGF-1R | 32 | 2 | 8 | 4 (1 repeat with detection rate <90%, rs2715415) | 19 |
| PlGF | 4 | 1 | 1 | 1 (repeat with detection rate <90%, rs4953402） | 2 |
FLT-1, Fms-like-tyrosine kinase; HWE, Hardy-Weinberg equilibrium; IGF-1, insulin-like growth factor 1; IGF-1R, insulin-like growth factor receptor 1; KDR, kinase insert domain-containing receptor; MAF, minor allele frequency; PlGF, placental growth factor; SNP, single nucleotide polymorphism; VEGFA, vascular endothelial growth factor A; VEGFB, vascular endothelial growth factor B.