Hemodynamic Parameters Of Inferior Adrenal Artery In Fetuses With Intrauterine Growth Restriction

Background:Fetal adrenal gland is one of the important endocrine organs,and secrete a variety of hormones.It plays an important role in fetal maturation and delivery activation.Normal blood supply can ensure the normal growth of adrenal gland and the exercise of its function.The premise of accurate evaluation of adrenal blood flow is to establish a normal reference range,but there are few studies on adrenal blood flow at home and abroad.Therefore,this study intends to evaluate the intrauterine development model of adrenal hemodynamics and to establish a normal reference range of hemodynamic parameters of the inferior adrenal artery of normal fetuses in the second and third trimester of pregnancy,so as to provide data for the development of adrenal function.Fetal intrauterine growth restriction(IUGR)is one of the common and complicated complications in obstetrics,which can not only lead to adverse pregnancy outcomes such as preterm delivery,stillbirth and neonatal asphyxia,but also affect its long-term growth and development,such as childhood IQ,physical fitness,cognitive impairment and so on.It is very important to detect and diagnose IUGR early and take intervention measures in time.At present,the measurement of various blood flow parameters by color Doppler ultrasound is an important method to monitor IUGR.The commonly used vessels include umbilical artery,middle cerebral artery,uterine artery,venous duct.When the fetus has ischemia and hypoxia,there is a "brain protective effect" in the fetus,in which the blood supply first ensures important organs such as the brain,heart and adrenal gland,where the blood vessels are dilated,and the blood vessels of the viscera and lower limbs contract.Under the effect of brain protection,fetal blood flow will be redistributed.The purpose of this paper is to explore the difference of adrenal blood flow parameters between IUGR fetus and normal fetus,so as to provide a new idea for prenatal evaluation of IUGR.This study consists of two parts:(1)Study on the reference range of Doppler hemodynamic parameters of inferior adrenal artery in normal fetus in the second and third trimester of pregnancy;(2)Study on pulsatility index of inferior adrenal artery in fetuses with intrauterine growth restriction.Chapter 1 Study on the reference range of Doppler hemodynamic parameters of inferior adrenal artery in normal fetus in the second and third trimester of pregnancyObjective:To study the hemodynamic parameters in fetal inferior adrenal artery of normal pregnancy and to determine the normal reference range in second and third trimester.Methods:A total of 604 pregnant women from 18 to 36 weeks who received routine prenatal ultrasonography were enrolled in this study.Fetal IAA peak systolic velocity(PSV),end-diastolic velocity(EDV),pulse index(PI)and resistance index(RI)were measured by pulse Doppler in oblique coronal section of both kidneys.The normal reference range related to GA was established.Pearson correlation analysis was used to test the correlation between IAA hemodynamic parameters and gestational age.Scatter plots were obtained for each parameter and GA,and various regression models were fitted to select the best fitting curve.Pregnancy outcomes were recorded and IAA hemodynamic parameters(PI,RI,PSV,EDV)of fetuses of different genders were compared.Results: Finally,594 fetuses were included.The pulse index(PI)and resistance index(RI)of IAA were negatively correlated with gestational weeks(P < 0.05,r=-0.73,-0.81),and the Cubic curve was the best fit.PI and RI of IAA remained unchanged at 1.03±0.06 and0.64±0.02 from 18 to 30 weeks of gestation,respectively.PI decreased from 0.97±0.05 to 0.79±0.03 and RI decreased from 0.61±0.01 to0.54±0.02 after 30 weeks of gestation.There was no significant correlation between peak systolic velocity(PSV)of IAA and gestational weeks.There was a slight positive correlation between end-diastolic velocity(EDV)and gestational weeks(P < 0.05,r=0.24)and the fitting degree of Cubic curve was the best.IAA hemodynamic parameters of fetuses of different genders were compared,and there was no significant difference.Conlusion: This study established a normal reference range of normal fetal IAA hemodynamic parameters in second and third trimester.,which is helpful to further evaluate fetal hemodynamics.Chapter 2 Study on pulsatility index of inferior adrenal artery in fetuses with intrauterine growth restrictionObjective: To investigate the characteristics of the pulsation index(PI)of the inferior adrenal artery(IAA)in fetuses with intrauterine growth restriction(IUGR).Methods: The inferior adrenal artery pulse index(IAA-PI)and perinatal outcomes were prospectively collected from 30 cases of IUGR with normal cerebroplacental blood flow ratio(CPR)and 30 cases of normal fetuses.The difference between the two groups of fetuses was compared.The correlation between IAA-PI and umbilical artery pulse index(UA-PI)was analyzed,and the correlation between IAA-PI and cerebroplacental blood flow ratio(CPR)was analyzed.The correlation between IAA-PI and perinatal outcome was also analyzed.Results: the IAA-PI of IUGR group was significantly lower than that of the normal control group(0.87vs1.14 at first scan and 0.80vs0.93 at last scan,P<0.001).Spearman correlation analysis showed that IAA-PI was negatively correlated with UA-PI at the first and last scan(P< 0.05,r=-0.51,-0.65).IAA-PI was positively correlated with CPR(P< 0.05,r=0.29,0.62).Neonatal weight at birth in the IUGR group was lower than that in the normal group(P<0.001).There was statistically significant difference of admitting neonatal intensive care unit rate between the two groups(P<0.01),but other perinatal indicators,such as Apgar score at 1 and 5 minutes,proportion of neonatal death,and cord blood p H,had no statistical significance between the two groups(P>0.05).Spearman correlation analysis showed that IAA-PI at the first and last scan was positively correlated with fetal birth weight(P < 0.05,r=0.64,0.41).Binary Logistic regression analysis showed that there was no significant correlation between IAA-PI at the first and last scan and neonatal admission to intensive care unit(P>0.05).Conclusion: IAA-PI decreased in fetuses with IUGR without cerebral protective effect,suggesting increased fetal adrenal blood flow.The correlation between IAA-PI and UA-PI and CPR indicates that IAA-PI can effectively evaluate fetal early blood redistribution in high-risk pregnancy,and can be used as one of the indexes to measure fetal intrauterine hemodynamics.