Abstract: Objective To explore the effects of admission time on labor duration and delivery mode among primiparas under new partogram. Methods A retrospective analysis was conducted on the data of 1 057 primiparas during January 2017 and December 2018. The subjects were divided into group A(n=913, cervical dilatation <3 cm)and group B(n=144, cervical dilatation ≥3 cm). The effects of admission time on delivery mode and obstetric outcomes were explored using univariate and multivariate Logistic regression analyses. Results Compared with group B, group A had larger BMI(F=5.489, P=0.019), longer gestational weeks(F=6.776, P=0.009), heavier fetal weight(F=9.721, P=0.002); higher rate of painless delivery(χ2=38.145, P<0.001), higher usage rate of oxytocin(χ2=10.416, P<0.001)and phloroglucin(χ2=6.481, P<0.001); longer first labor duration(F=51.05, P<0.001), total labor duration(F=49.76, P<0.001)and hospitalization(F=40.613, P<0.001); higher rate of Cesarean section(χ2=3.929, P=0.047), higher incidence of fetal distress(χ2=5.085, P=0.024), and larger amount of postpartum bleeding(F=6.724, P=0.01). Multiple Logistic analysis revealed that early admission was independently associated with prolonged first stage of labor(OR=3.347, 95%CI=2.062-5.431)and total duration of labor(OR=3.792, 95%CI=2.292-6.271). Conclusion Admission when cervical dilatation ≥3 cm could avoid unnecessary interventions, shorten the stage of labor, reduce the high rate of Cesarean delivery and improve the pregnancy outcomes.

Key words: Cervical dilatation, Vaginal delivery, Stages of labor, Caesarean delivery