Frequency of HLA‑G UTR‑1/UTR‑3/UTR‑7 in women with unexplained recurrent spontaneous abortion.

Human leukocyte antigen (HLA)-G is an important molecule that maintains maternal-fetal interface tolerance and plays a vital role in a healthy pregnancy. Single-nucleotide polymorphisms in the 3'-untranslated regions (UTR) of the HLA-G gene may differ in women with unexplained recurrent spontaneous abortion (URSA). The present study involved the isolation of genome DNA from peripheral blood leukocytes, Sanger sequencing and analysis of the polymorphism sites in the 3'UTR of the HLA-G gene based on polymerase chain reaction. In total, 261 DNA samples from cases of URSA (n=133), including primary URSA (n=83) and secondary URSA (n=50), and controls (n=128) were evaluated. The present data showed that +3010CC genotype carriers exhibited a higher risk of URSA, while +3187GG genotype carriers exhibited a lower risk. Secondary URSA patients carrying +3010C had a higher risk of URSA, while +3187G carriers exhibited a lower risk of URSA. UTR-1 haplotype carriers may be associated with a reduced risk of primary and secondary URSA. Notably, UTR-3 and UTR-7 could increase the risk of primary and secondary URSA, respectively. The present results showed that HLA-G 3'UTR polymorphisms and haplotypes may be involved in URSA development and be a predictor of pregnancy outcome.