en 28706612 <p>Background: Recurrent Spontaneous Abortion (RSA) is caused by multiple genetic and non-genetic factors. Around 50% of the RSA cases have no known etiology and are considered as Unexplained RSA (URSA). Estrogens, <em>via</em> binding to their receptors, play an important role in female reproduction. This study aimed to investigate whether single nucleotide polymorphisms (SNPs; +1082G/A, +1730G/A and rs1256030C/T) in the estrogen receptor beta (<em>ESR2</em>) gene are associated with susceptibility to URSA in a population of Iranian women.<br /> Methods: In this case-control study, the study groups consisted of 240 subjects with a history of URSA and 102 fertile women as controls. Serum levels of follicle stimulating hormone (FSH), luteinizing hormone (LH), and estradiol (E2) were measured on day 2-3 of menstrual cycle. Two functional SNPs, +1082G/A (a silent mutation in exon 5) and +1730G/A (3&#39; untranslated region of the exon 8),and one intron,rs1256030C/T, in the ESR2 gene were genotyped, using polymerase chain reaction- restriction fragment length polymorphism (PCR-RFLP) analysis.<br /> Results: Serum levels of LH were significantly increased in URSA women. No significant differences in distribution of +1082G/A, +1730G/A and rs1256030C/T between URSA and control groups were observed.<br /> Conclusion: Our findings suggest that the studied SNPs on <em>ESR2</em> gene may not be associated with URSA.</p> Estrogen receptor, Habitual abortion, Polymerase chain reaction, Restriction fragment length polymorphism, Single-nucleotide polymorphism 150 154 https://www.ajmb.org/En/Article.aspx?id=284 https://www.ajmb.org/PDF/En/FullText/284.pdf MarziehMahdavipourReproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran1149SaeedZareiMonoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran1150RaminaFatemiReproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran849HalehEdalatkhahReproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran1151HamedHeidari-ValaReproductive Biotechnology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran258MahmoodJeddi-TehraniMonoclonal Antibody Research Center, Avicenna Research Institute, ACECR, Tehran, Iran15FarahIdaliReproductive Immunology Research Center, Avicenna Research Institute, ACECR, Tehran, Iran855