Recurrent miscarriage is associated with the dopamine receptor (DRD2) genotype.

The purpose of this research is to compare the prevalence of dopamine receptor D2 polymorphisms in women with recurrent miscarriage (RM) and healthy patients. Fifty-four women were enrolled in this case-control study. We performed DNA extraction of peripheral blood, followed by polymerase chain reaction to confirm single-strand polymorphisms and to sequence two polymorphisms: polymorphism 1 (rs6275) and polymorphism 2 (rs6277) in exon 7 of the dopamine receptor D2 (DRD2). The frequency of DRD2 polymorphism 2 (rs6277) was increased in the subjects with RM. An analysis of the DRD2 genotypes demonstrated an odds ratio of 2.37 (1.05-5.36, 95% confidence interval) for the polymorphism 2 (rs6277) in RM. The mean of the serum prolactin level was higher in the patients with RM (12.5 ng/ml) than in healthy women (8.1 ng/ml) p = 0.03. An excess homozygosity of the DRD2 polymorphism suggests a genetic predisposition to RMs, which could result in a mild serum prolactin increase. Thus, because of the potential role of prolactin in reproductive regulation, this polymorphism could play an important role in early pregnancy implantation and pregnancy maintenance.