Analysis Of Elective Induction Of Labor On Pregnancy Outcome In Low-risk Pregnant Women With Late-term Pregnancies

ObjectiveThe pregnancy outcome and related factors of elective induction of labor in low-risk pregnant women with late-term pregnancies were analyzed retrospectively,objective to investigate the effect of induced labor on maternal and fetal pregnancy outcome.MethodsWe conducted the method of retrospective observation and control study involving a total of 4386 pregnant women were examined and delivered in Fujian Maternal and Child Health Hospital from January 2014 to December 2018.The study was restricted to singleton low-risk cephalic hospital vaginal birth at or more than 41 weeks 0 days of gestation.According to the mode of labor initiation,they were divided into 2007 pregnant women whose labor induction and 2361 pregnant women with natural labor process.The clinical data of pregnant women in the two groups were collected and compared.The differences in related of pregnancy outcome between the two groups were as follows:(1)general conditions: gestational weeks,age,number of pregnancies and parturients,etc.(2)delivery conditions: duration of each stage and total stage of labor,operative vaginal birth,3rd/4th-Degree laceration,amniotic fluid contamination.(3)maternal complications: incidence of postpartum hemorrhage,incidence of severe postpartum hemorrhage and postpartum blood loss,puerperal infection,placental abruption,etc.(4)neonatal outcome: birth weight,sex,Apgar <7score at birth,respiratory complication,hyperbilirubinemia,neonatal intensive care unit admission,neonatal survival and so on.According to the mode of induced labor,the induced labor group was divided into 7 subgroups:(1)induced by Foley catheter(n=179);(2)induced by dinoprostone(n=102);(3)induced by oxytocin(n=865)(4)induced by misoprostol(n=77);(5)induced by Foley catheter combined with oxytocin(n=732);(6)induced by dinoprostone combined with oxytocin(n=36);(7)induced by misoprostol combined with oxytocin(n=16).The pregnancy outcomes of different subgroups were compared and analyzed.Results1.General conditions:(1)The total duration of labor and the duration of each stage of labor in the selective induced labor group were more than those in the natural labor group,and there were significant differences in the first and second stages of labor and the total duration of labor between the two groups(P<0.05).(2)The number of parturients in the natural labor group was higher than that in the selective induced labor group(33.4 % vs 29.0 %),and the difference was statistically significant.(3)The gestational age in the induced labor group(289.26 ± 1.54 days)was longer than that in the natural labor group(288.33 ± 1.62 days),and the difference was statistically significant(P<0.05).2.Delivery conditions:(1)The total duration of labor and the duration of each stage of labor in the selective induced labor group were more than those in the natural labor group,and there were significant differences in the first and second stages of labor and the total duration of labor between the two groups(P<0.05).(2)The amount of postpartum blood loss in the selective induced labor group increased with the increase of the total duration of labor,and increased significantly when the total stage of labor was ≥ 20 hours.3.Maternal complications:(1)The rate of operative vaginal birth in the selective induced labor group was significantly higher than that in the natural labor group(3.5 % vs 5.0 %)(P<0.05).(2)The incidence of chorioamnionitis in the selective induced labor group was significantly higher than that in the natural labor group(4.33 % vs 2.33 %).There was no significant difference in the incidence of third degree amniotic fluid contamination(15.5 % vs 14.7 %)and placental abruption(4.48 % vs 2.96 %)between the two groups.(3)The average postpartum blood loss(219.18 ±188.32 m L vs 199.95 ±124.69 m L)and the incidence of severe postpartum hemorrhage(0.8 % vs 0.33 %)in the selective induction group were significantly higher than those in the natural labor group.There was difference in the incidence of PPH between the two groups(3.8 % vs 2.8 %),but there was no significant difference between the two groups(P>0.05).(4)The pregnant women aged between 18 ～ 34 years old,the incidence of postpartum hemorrhage and severe postpartum hemorrhage in the selective induced labor group was significantly higher than that in the natural labor group(2.5% vs 3.69%;RR,1.481;95% CI,1.508～2.073),and the difference was statistically significant(P<0.05).(5)Among the primipara,the incidence of PPH in the selective induced labor group was higher than that in the natural labor group(2.74 % vs 1.65 %;RR,1.557;95 %CI,1.039～2.332),and there was significant difference(P<0.05).4.Neonatal outcome:The NICU admission rate of newborns in selective induced labor group was significantly higher than that in natural labor group(P<0.05).However,there was no significant difference between the two groups in birth weight and its distribution,sex of newborn,incidence of neonatal brain injury,incidence of neonatal intraventricular hemorrhage,perinatal death,neonatal hyperbilirubinemia,neonatal septicemia,neonatal pneumonia and Apgar ≤ 7 at birth(P>0.05).5.Comparison of different ways of induced labor:(1)The total duration of labor was different in different ways of induced labor,and the difference was statistically significant(P<0.05).Among them,the total duration of labor induced by dinoprostone alone is the shortest,and the total duration of labor induced by dinoprostone combined with oxytocin is the longest.(2)There was no significant difference in the incidence of forceps delivery,chorioamnionitis,amniotic fluid contamination and placental abruption among different methods of induced labor(P>0.05).There was no significant difference in the incidence of neonatal hyperbilirubinemia,neonatal Apgar score ≤ 7,neonatal septicemia,neonatal pneumonia and neonatal intraventricular hemorrhage among different methods of induced labor(P>0.05).Conclusion1.Selective induction of labor increases the complications of mother and child.During induction of labor,the labor process should be closely monitored to prevent related complications.Low-risk pregnant women should try to avoid induction without medical indications.2.When selective labor induction is carried out for low-risk primary parturients with delayed pregnancy,attention should be paid to the control of the duration of labor,especially when the total duration of labor is ≥ 20 hours,attention should be paid to the active prevention and treatment of postpartum hemorrhage.3.When the low-risk pregnant women with delayed pregnancy choose Dinoprostone to induce labor,the total duration of labor induction is shorter than that of other methods,and its safety is not lower than that of other methods of induced labor.