Clinical Study On The Optimal Time To Delay Umbilical Cord Clamping

Objective:To compare the analysis of umbilical cord blood gas(pH,HCO3~-,PaCO2,BEecf,PaO2),Apgar scores within 10 minutes of birth,and percutaneous oxygen saturation(SpO2)within 10 minutes of birth,hemoglobin(Hb)and hematocrit(Hct),percutaneous bilirubin values and number of jaundice requiring phototherapy within 72 hours of birth,average arterial pressure(MAP)within 24 hours of birth and the ratio of neonatal polycythaemia(NP);Meanwhile,to observe the amount of bleeding at 2-hour(h)after delivery,the duration of the third stage of labor,the changes of pre-and post-birth Hb and Hct.To explore the optimal time of the newborn umbilical cord clamping,and whether delayed umbilical cord clamping is more beneficial to newborns than harms,whether it can reduce maternal and neonatal complications,which contribute to the cause of women's and children's health in our hospital and even in my city.Method:230 full-term pregnant women underwent vaginal delivery and their baby at Yan‘an University Affiliated Hospital were selected randomly from June 2019 to January 2020.According to the time from the newborn's full delivery to the clamping of the umbilical cord,the subjects were divided into 5 groups by the time from complete delivery of the newborn to the umbilical cord clamping,i.e.Group A(immediately cord clamping(<30s),Group B(1 minute after birth),Group C(2min after birth),and Group D(3min after birth))and Group E(Umbilical artery pulse disappearance),umbilical cord blood gas analysis by midwives within 30s after birth,Apgar score and SpO2 monitored by resident doctors within 10 minutes of birth;Blood pressure monitored and recorded by an obstetric professional nurse once every 2 hours in the first 4 hours after birth,after that,the measurement frequency will be changed once every 4 hours until 24 hours after birth.While the newborns are measured percutaneously bilirubin values twice a day during hospitalization(Each result is the average of the three values of forehead,abdomen and back),scalp vein blood collection was performed for blood routine at 72 hours after birth;the neonatal erythrocytosis and jaundice requiring phototherapy were counted during the hospitalization;At the same time,a curved plate was used to collect the amount of bleeding after delivery and record the duration of the third stage of labor.The postpartum blood routine was performed at 24 hours and compared with the results of admission.Result:1.With the extension of the umbilical cord clamping time,the difference in Hct before and after delivery between the 2-min and 3-min DCC group were smaller than whose of the ICC and 1-min DCC group,while the Hb difference among different groups was not statistically significant(?>0.05);Duration of the third stage of labor in the 3-min DCC was shorter than of whose in ICC,1-min DCC,2-min DCC,and the difference among the groups were no statistically significant(?>0.05).2.Hb and Hct were higher in the 3-min DCC group than in the ICC group,but the difference in the incidence of NP among the groups was not statistically significant(?>0.05).3.There was no significant difference in Apgar scores at 1 min,5 min,and 10 min after birth among the groups(?>0.05);4.With the extension of the umbilical cord clamping time,the umbilical artery PaCO2levels and PaO2 levels gradually increased,but PaCO2 and PaO2 between DCC of 2-min and 3-min were not statistically significant(?>0.05);With the extension of the umbilical cord time,the BEecf of the umbilical arterial blood gradually decreased and reached the lowest value in 2-min DCC group,and thereafter gradually increased.But,there was no significant difference in the BEecf of cord blood between the 3-min DCC group and the 2-min DCC group(?>0.05);There was no statistically significant difference in umbilical cord blood pH and HCO3~-among the groups(?>0.05).5.With the extension of DCC time,the value of percutaneous bilirubin increased gradually on the first day and second day after birth,and the bilirubin value reached a peak at DCC of 3min;The difference of the percutaneous bilirubin among the groups was no statistically significant(?>0.05);With the extension of DCC time,the number of neonates with jaundice who require phototherapy had no statistical significance among groups(?>0.05).6.SpO2 value per minute increased gradually within the first 10 minutes after birth;with the extension of the time of DCC,the differences of the SpO2 value between the groups of 1min,2min,3,4min,5min,6min,7min,and 8min were statistically significant(?<0.05),while the difference of the SpO2 value monitored at the 9min and 10min after birth among the groups were not statistically significant(?<0.05);with the extension of the time of DCC,the median(M)of the SpO2 value in the first 10 minutes of newborn life increased gradually;With the extension of the DCC time,the median of the SpO2 per minute after birth gradually increased.7.With the extension of the DCC time,the difference of the MAP values at 0h?2h?4h?8h?12h and 20h after birth were statistically significant(?<0.05);The 24h MAP after birth presents fluctuation trends,with the lowest MAP values at 2h and 16h after birth,and the difference with other time periods was statistically significant(?<0.05);the median of MAP value monitored at 2min after birth at DCC of 3min was higher than the median of MAP value at ICC group and 1 min delayed cord clamping group,the difference was statistically significant(?<0.05);With the extension of umbilical cord clamping time,the stability of 24h MAP in newborns is higher.Conclusions:1.DCC does not increase the risk of neonatal polycythemia while increasing the blood volume of the newborn;DCC increased risk of hyperbilirubinemia,of which the growth rate decreases gradually at the 72 hours after birth.Meanwhile,DCC does not increase the incidence of jaundice requiring phototherapy.The MAP value of 2h after birth is the lowest,DCC can increase the level of MAP and increase the stability of MAP fluctuations,thereby which could reduce the incidence of low blood pressure in newborns;The implementation of DCC can increase the blood oxygenation level,and which reduce neonatal complications and mortality further;2.DCC can decurtate the duration of the third stage of labor and does not increase the incidence of postpartum hemorrhage,which can be used as a preventive measure of postpartum hemorrhage in clinical practice.3.It is recommended that regard 2min as the optimal umbilical cord timing in healthy full-term infants,which can not only reduce the incidence of neonatal acidosis,but also increase the stability of the neonatal cycle transition period.Meanwhile,it does not increase the incidence of neonatal pathological jaundice.