| Objectives To explore the effect of different duration of the first and second stage of labor on the outcome of childbirth in nulliparous women.Methods Using a retrospective cohort study,3501 parturients were enrolled in the obstetric hospital of Hebei general hospital from January 2018 to April 2019.According to the inclusion exclusion criteria,2777 cases were excluded and 724 cases remained.According to the duration of the first stage,they were divided into four subgroups:<6h(377cases),6-11.9h(267cases),12-17.9h(62cases),≥18h(18cases);According to the duration of the second stage,they were divided into five subgroups:<0.5h(257cases),0.5-0.9h(259cases),1-1.4h(121cases),1.5-1.9h(55cases),≥2h(32cases).The compared clinical indexes in the subgroups of first stage and the second stage including:instrumental delivery,spontaneous labor,postpartum hemorrhage≥300ml,neonatal outcomes,Apgar≤7(1min),neonatal admission,neonatal infection,aspiration syndrome,metabolic acidosis,hypoxic-ischemic encephalopathy.The database was established by excel software,and the statistical data were analyzed by SPSS 21.0.The measurement data were expressed by median and quartile spacing,Mann-Whitney rank sum test;the counting data were expressed by composition ratio,chi-square test or calibration chi-square test.Logistic regression model was used to explore the effect of different duration of the first stage and second stage of labor on the outcomes.the Excel table prepared by Andresson was used to calculate the adding interaction.Results With the prolongation of first stage,the rates of instrumental delivery,neonatal outcomes,Apgar≤7(1min)and neonatal admission increased,which increased significantly(P<0.001).the rates of spontaneous labor reduced.With<6h as the reference,multivariable logistic regression showed that ARR(95%CI)of instrumental delivery were 1.06(0.7,1.62),1.14(0.58,2.24),4.63(1.75,12.29)in subgroups of 6-11.9h,12-17.9h,≥18h;The ARR(95%CI)of spontaneous labor were 0.94(0.42,1.43),0.88(0.45,1.73),0.22(0.08,0.57);The ARR(95%CI)of neonatal outcomes were 1.07(0.61,1.86),2.30(1.11,4.78),5.06(1.77,14.51);In order to understand the impact of different cutoff values on the risk of adverse outcomes,the first stage<6h and≥6h were compared,the first stage<12h and≥12h were compared,the first stage<18h and≥18h were compared,the ARR(95%CI)of instrumental delivery were 1.19(0.81,1.75),1.62(0.94,2.76),4.46(1.72,11.61);the ARR(95%CI)of spontaneous labor were 0.84(0.57,1.23),0.62(0.36,1.06),0.22(0.09,0.58);The ARR(95%CI)of neonatal outcomes were 1.44(0.89,2.36),2.75(1.52,4.97),4.49(1.62,12.44).With the prolongation of second stage,the rates of instrumental delivery,neonatal outcomes,Apgar≤7(1min),neonatal admission,neonatal infection,aspiration syndrome of newborn,metabolic acidosis and hypoxic-ischemic encephalopathy increased,which increased significantly(P<0.001).The rates of spontaneous labor reduced(χ~2=43.91,P<0.001).With<0.5h as the reference group of second stage,ARR(95%CI)of 0.5-0.9h,1-1.4h,1.5-1.9h,≥2h were 0.60(0.37,0.99),0.89(0.50,1.58),2.64(1.39,5.01),4.98(2.26,10.98)in instrumental delivery.ARR(95%CI)were 1.66(1.02,2.72),1.12(0.63,1.99),0.38(0.20,0.72),0.2(0.09,0.44)in spontaneous labor.ARR(95%CI)were 0.73(0.34,1.56),1.78(0.82,3.85),7.94(3.72,16.93),17.64(7.22,43.08)in neonatal outcomes.Regarding the impact of cutoff values of second stage on the risk of adverse outcomes,ARR(95%CI)of neonatal outcomes was 2.1(1.22,3.84)with 0.5h as the cutoff values.The ARR(95%CI)of instrumental delivery were 2.1(1.44,3.15),4.1(2.55,6.72),5.48(2.61,11.54)with 1h,1.5h,2h as the cutoff values.The ARR(95%CI)of spontaneous labor were 0.47(0.32,0.70),0.24(0.15,0.39),0.18(0.09,0.38),ARR(95%CI)of neonatal outcomes were 5.30(3.19,8.78),10.34(6.02,17.78),12.26(5.68,26.45).The effects of first stage>6h and the second stage>1h on delivery outcomes are not additive interactions(RERI=-0.528,AP=-0.214,SI=0.736),as well as multiplying interactions 0.68(0.32,1.47).Conclusions 1 With increasing the length of first stage of labor,the rates of adverse outcomes are increasing,the rates of spontaneous labor are reducing,The length of the first stage of labor is an independent risk factor for adverse labor outcomes.2 When the length of the first stage of labor was>18 hours,adverse outcomes were significantly increased,therefore,when the length of the first stage of labor exceeds 18 hours,clinicians should take measures to end the delivery process as soon as possible in order to reduce the occurrence of adverse outcomes.3 With increasing the length of second stage of labor,the rates of adverse outcomes are increasing,the rates of spontaneous labor are reducing,The length of the second stage of labor is an independent risk factor for adverse labor outcomes.4 When the length of the second stage of labor was>2h,the adverse outcome rates are doubled,and the spontaneous labor rates are decreased.When the length of the second stage of labor was>2h,the clinical workers should finish the labor process as soon as possible.5 The effects of first stage>6h and the second stage>1h on delivery outcomes are not additive interactions,as well as multiplying interactions.Figure 1;Table 10;Reference 134... |
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