Estrogen receptor alpha and beta gene polymorphisms are not risk factors for recurrent miscarriage in a Brazilian population.

The aim of this study was to determine the prevalence of alpha (ESR1: c.454-397T>C and c.454-351A>G) and beta (ESR2: 1082G>A and 1730G>A) estrogen receptor gene polymorphisms in 2 Brazilian ethnic groups (Caucasian, African Brazilian) and to investigate their association with recurrent miscarriage (RM) in 75 women with a history of 3 or more consecutive pregnancy losses and 139 controls with at least 2 live births and no history of pregnancy loss. Polymerase chain reaction and restriction fragment length polymorphism were used to identify gene polymorphisms. Coagulation methods were used to measure protein C, protein S, and fibrinogen, and a chromogenic method was used for antithrombin quantification. Significantly higher prevalences of 1082G>A and 1730G>A polymorphisms were seen in African Brazilian and Caucasian controls, respectively. There was no association between RM and ESR polymorphisms. There was a difference in the genotype prevalence in the c.454-39T>C polymorphism between RM and control Caucasians, but this finding was not associated with an increased risk of miscarriage. There was no synergistic or additive effect between ESR polymorphisms and thrombophilia in RM patients. A difference in the prevalence of ESR polymorphisms was observed, according to ethnic origin. ESR polymorphisms could not be considered a risk factor for RM.