Abstract: Objective To investigate the relationship between rs7227488 polymorphism site at the gene promoter region of miR-122 and the susceptibility of intrauterine infection in HBsAg-positive pregnant women. Methods One hundred and fourty-one HBsAg positive pregnant women who underwent prenatal examination and deliveried were selected in this study. General data of the pregnant women (age, gestational week at delivery, mode of delivery, sex of newborn) were collected. The HBsAg-positive pregnant women were divided into HBV intrauterine infection group (47 cases) and non-HBV intrauterine infection group (94 cases) according to the occurance of HBV infection in their neonates. The rs 7227488 polymorphism of miR 122 gene in all subjects was detected using polymerase chain reaction-restriction fragment length polymorphism (PCR-RELP). Risk factors of HBV intrauterine infection in HBsAg positive pregnant women and the correlation between rs7227488 and neonatal HBV infection were analyzed by logistic regression analysis. Results The G/A genotypes of rs7227488 in non-HBV intrauterine infection group and HBV intrauterine infection group were accordant with Hardy-Weinberg equilibrium law (P>0.05). The G/A mutation rate of rs7227488 in non-HBV intrauterine infection group (44.6%) was significantly higher than that of the HBV intrauterine infected group (55.3%) (P<0.05). Bivariate logistic regression analysis showed that HBV DNA load and rs7227488 AA type were risk factors for intrauterine HBV infection in HBsAg-positive pregnant women (Or=1.512,1.898,all P<0.05). Conclusion The miR-122 rs7227488 AA genotype of HBsAg-positive pregnant and lying-in women are risk factors of intrauterine HBV infection.

Key words: Hepatitis B virus, MicroRNA-122, Gene polymorphism, Intrauterine infection