['In this study, we assessed whether the single nucleotide polymorphism in the murine double minute 2 (MDM2) promoter (SNP309) was associated with the occurrence of missed abortion.', 'Genotyping of MDM2 SNP309 polymorphism was conducted by polymerase chain reaction-restriction fragment length polymorphism with blood and villous samples from 95 women diagnosed as having 1st trimester missed abortion.', 'The MDM2 SNP309 G/G genotype was associated with a higher risk of missed abortion compared with the T/T+ T/G genotype in blood (P = 0.010; odds ratio (OR): 2.164; 95% confidence interval (CI): 1.207-3.878) and villous samples (P = 0.043; OR: 2.767; 95% CI: 1.092-7.011).'] Is mDM2 309 polymorphism associated with missed abortion?