The interaction between p53 and human double minute 2 (HDM2) plays an important role in apoptosis; therefore, functional polymorphisms in these genes might have adverse effects in early pregnancy.
The down-regulated elements included the tumor suppressor TP53, genes related to apoptosis such as GADD34, GADD45A, GADD45B and PIG11, and the gene encoding OVGP1, a protein involved in maintenance of early pregnancy.