Objective: Progesterone inhibits lymphocyte cytotoxicity, natural killer cell degranulation, and release of proinflammatory cytokines and has been shown to protect against spontaneous miscarriage. We investigated the association between idiopathic recurrent miscarriage (IRM) and the PROGINS 306 base pair insertion polymorphism in intron G of the progesterone receptor gene, which is known to segregate with progesterone-dependent neoplasms.
Methods: In a case-control study we investigated 125 women with a history of three or more consecutive pregnancy losses before 20 weeks' gestation and 79 healthy controls with at least two live births and no history of pregnancy loss. Peripheral venous puncture, DNA extraction, and polymerase chain reaction were used to genotype women for the presence of the PROGINS polymorphism.
Results: Allele frequencies among women with IRM and controls were 85.2% and 89.2%, respectively, for allele T1 (wild type) and 14.8% and 10.8%, respectively, for allele T2 (mutant). No association between allele T2 and the occurrence of IRM was found (P =.3; odds ratio [OR] 0.69; confidence interval [CI] 0.34, 1.40). Genotype frequencies were not significantly different between the study group (T1/T1 73.6%, T1/T2 23.2%, T2/T2 3.2%) and the control group (T1/T1 79.7%, T1/T2 19%, T2/T2 1.3%) (P =.4). Between women with primary and secondary IRM, there were no statistically significant differences with respect to allele frequencies (82% versus 87%, P =.4 for allele T1 and 12% versus 13%, P =.6 for allele T2).
Conclusions: We found that the PROGINS polymorphism in the progesterone receptor gene was not associated with IRM in white women.