The ESR1 gene in unexplained recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is a health problem that affects nearly 1% of fertile couples. However, the underlying etiology and mechanism(s) remain elusive. The aim of this study was to investigate estrogen receptor (ESR) 1 gene polymorphisms for risk association of unexplained recurrent spontaneous abortion (URSA) in the Chinese Han population. The entire coding region of the ESR1 gene was sequenced from 129 URSA patients and 183 healthy controls. There was a significant difference between the G allele and GG genotype distributions, of the ESR1 gene (XbaI) polymorphism, between the URSA and the control groups (chi(2) = 14.93, df = 1, p < 0.001, OR = 2.01 95% CI: 1.41-2.88 by allele; chi(2) = 12.24, df = 2, p = 0.002 by genotype). The PvuII polymorphism, C allele frequency was higher in RSA than in controls (41.9% vs. 34.7%, respectively). Women carrying C-G haplotype were associated with an increased risk of URSA in this population (permutation test p value = 0.016, OR = 1.76 95% CI: 1.19-2.59). Estrogen receptor 1 gene PvuII and XbaI polymorphisms were associated with URSA in a Chinese Han population. However, independent replication of these associations are necessary to assure veracity.