RÉSUMÉ
Objective To investigate the distribution ofβ2-adrenergic receptor (β2-AR)genetic polymorphisms among the included parturient women and observe the relationship between the genetic polymorphisms and labor progress after labor analgesia.Methods A prospective observational study was conducted from March to June in 2014 at Nanjing Maternity and Child Health Care Hospi-tal.A total of 1 65 nulliparous women were enrolled in the study,and finally 1 52 patients were includ-ed after exclusion for several reasons.Theβ2-AR gene polymorphic variations at nucleotides encoding amino acids 1 6 and 27 were detected by polymerase chain reaction-restriction fragment length poly-morphism technique.And the demographic data,rate of oxytocin usage,length of labor progress and the incidence of cesarean section after labor analgesia were observed and recorded.Results The allele frequencies ofβ2-AR genetic polymorphism in the parturient women were dominantly presented in the form of Arg1 6Arg (AA)and Arg1 6Gly (AG)at 1 6 position and Gln27Gln(CC)at 27 position respec-tively.The demographic and background characteristics of the subjects didn’t present any significant differences among the groups with differentβ2-AR genetic polymorphism.And the differences of labor progress among β2-AR 27 genetic polymorphisms parturient women were not significant.However, the length of the first stage and the total labor progress in the β2-AR Arg1 6Arg homozygous were both significantly longer than that in the other two groups (P <0.05),and the incidence of cesarean section was also significantly higher (P <0.05 ).Furthermore,we also found that β2-AR Arg1 6Arg homozygous was related to cesarean delivery after labor analgesia through multivariate logistic regres-sion analysis (OR 2.87,95%CI 2.69-3.09).Conclusion The labor progress of the parturient women with β2-AR Arg1 6Arg homozygous is relatively slower,which maybe an important risk for the nullip-arous women transforming to cesarean delivery after labor analgesia.