Ultrasonographic Study On The Changes Of Fetal Heart Size And Shape Of Small For Gestational Age Fetuses

Objective:To investigate whether various types of small for gestational age（SGA）fetuses have changes in the shape and size of the heart;whether the global sphericity index（GSI）and area（A）are more sensitive than the hemodynamic indicators that have been widely used in the past,and whether it can be used as an early monitoring indicator for SGA fetuses.Method:SGA fetuses who were admitted to the Department of ultrasound in the First Affiliated Hospital of Hainan Medical University from June 2020 to February 2021（SGA is defined as fetuses whose body weight or abdominal circumference was less than the 10th percentile in the same gestational age as estimated by ultrasound）were selected.A total of 77 patients were included in the study and divided into healthy small fetuses group（42 cases）and fetal growth restriction group（35 cases）.50 cases of fetuses with normal growth and development（the weight estimated by ultrasound was between the 10th and 95th percentiles of fetuses at the same gestational age）were selected as normal control group（no obvious structural malformations and genetic abnormalities）.All pregnant women received ultrasound at 20 weeks to 40 weeks gestation,in addition to the regular prenatal ultrasonic examination content and measurement of fetal growth parameters,the need for fetal cardiac four-chamber view after dynamic image storage,playback end-diastolic measurement after fetal heart length to diameter D1 and heart diameter D2,according to the formula to calculate fetal heart global spherical index（GSI）and the area（A）;At the same time,maternal-fetal hemodynamic indicators were detected,including bilateral maternal uterine arteries,fetal umbilical arteries,middle cerebral arteries and venous ducts.All the fetuses included in the study and the normal control group were followed up until after birth and before leaving the hospital.The 5th of the fetus with the same gestational age was abnormal,and the 95th of the fetus with the same gestational age was abnormal.The number of cases with abnormal GSI and A of the normal control group,healthy small fetuses group and fetal growth restriction group were counted and compared pairwise;The number and incidence of abnormal cases of GSI and A in the heart of early FGR and late FGR in fetuses with different onset times of growth restriction group were counted and compared.The cases and incidence of abnormal heart GSI and A in mild FGR and severe FGR were compared.Comparison of the number and incidence of cardiac GSI and A abnormalities between FGR with abnormal fetal hemodynamics and FGR without abnormal fetal hemodynamicsResult:The median gestational weeks at delivery in the three groups were 39W⁺¹in the normal control group,38W⁺⁶in the healthy small sample group and 34W⁺³in the growth restriction group.The gestational age of the normal control group and the healthy small fetuses group was greater than that of the growth restriction group（P<0.001）;Comparison of gestational age between healthy small fetuses and normal control group（P>0.05）.The number and incidence of abnormal GSI and A in the fetal growth restriction group were higher than those in the healthy small fetuses group and the normal control group（P<0.05）.The number and incidence of abnormal parameters GSI and A in healthy small fetuses group were higher than those in normal control group（P<0.05）.There was no statistical significance in the number and incidence of abnormal cases of GSI and A between early-onset FGR and late-onset FGR（P>0.05）.There was no statistical significance in the number and incidence of cardiac GSI and A abnormalities between mild FGR and severe FGR（P>0.05）.Comparison of the number and incidence of cardiac GSI and A abnormalities between FGR with abnormal fetal hemodynamics and FGR without abnormal fetal hemodynamicss（P>0.05）.Conclusion:Although healthy small fetuses weigh less than fetuses of the same gestational age,their gestation period can generally be maintained to the ideal gestational age.Even in the absence of any maternal-fetal hemodynamic abnormalities,a significant number of fetuses with SGA showed changes in heart shape and size（33%and 31%）.Therefore,the GSI and A of fetal heart are more sensitive than the previously widely used hemodynamic indexes,and can be used as early monitoring indexes of fetal SGA.FGR can cause fetal heart remodeling in utero regardless of the time of onset,severity of the disease and the presence of fetal hemodynamic abnormalities,with changes in heart size and shape,the decrease of GSI and the increase of A.Regardless of the time of onset of FGR,the severity of the disease,and the presence or absence of fetal hemodynamic abnormalities,fetal heart remodeling can occur in the uterus,with changes in the size and shape of the heart,that is,a decrease in GSI and an increase in A.