Research And Establishment Of The Growth Curve And Reference Range Of Chinese Fetal Ultrasound Biological Parameters

Objective1.This study aimed to construct new reference charts and equations for fetal biometry from Chinese fetuses at 15?40 weeks.2.The results of this study were compared with other studies to determine the reference range for Chinese fetuses.MethodThis was a multi-center prospective,cross—sectional study of singleton pregnancies in patients with a confirmed gestational age who underwent ultrasound examinations between the 15th and 40th weeks of gestation.Each woman was selected only once for this study.Biparietal diameter(BPD),head circumference(HC),abdominal circumference(AC),and femur length(FL)were recorded.For each measurement,separate regression models were fitted to estimate the mean and standard deviation at each menstrual age.Z-scores were calculated with our reference equations for comparison with other references.Results1.New charts and reference equations involving 7553 Chinese women were created for BPD,HC,AC,and FL.Reference equations were cubic models.BPD=66.62190+3.02717(GA-26)-0.02264(GA-26)2-0.00366(GA-26)3(R2=0.9522)HC=243.08436+10.21927(GA-26)-0.15379(GA-26)2-0.00860(GA-26)3(R2=0.9578)AC=220.22188+10.90063(GA-26)+0.00939(GA-26)2-0.00905(GA-26)3(R2=0.9533)FL=48.32225+2.41233(GA-26)-0.02623(GA-26)2-0.00056(GA-26)3(R2=0.9583)2.The reference equations of standard deviation(SD)of BPD,HC,AC and FL were established in this study.The reference equations of the parameters of SD are all linear equations.BPD(mm)=2.24668+0.03120 GA HC(mm)=6.46603+0.11823 GA AC(mm)=1.81467+0.36755 GA FL(mm)=1.29105+0.04187 GA3.Prediction intervals for the new reference charts were similar to those of previous references,but with some slight differences.The main difference in our fetal biometric measurements compared with those of Korea and Hong Kong was the FL.The AC and FL measurements in INTERGROWTH-21st were lower than that of our study.After 20?21 weeks of gestation,the HC,AC and FL measurements were were similar to this new reference chart.ConclusionWe report new Chinese reference charts and equations for fetal biometry.These reference charts and equations are available for clinical use in obstetric ultrasound studies for the Chinese population.Objective1.To develop a sonographic dating formula based on fetal crown-rump length(CRL)in a Chinese population,quantify its systematic prediction error and compare its performance with established dating formulae.2.To establish reference values for the nuchal translucency(NT)in a Chinese population.Method1.This was a prospective observational study.From 2008 to 2012,13 tertiary and first-class hospitals in China enrolled pregnant women in 1st trimester and underwent ultrasound examination during pregnancy.All the women were routinely followed up until the birth of the fetus.2.Women with a spontaneously conceived singleton pregnancy and a regular menstrual cycle in the preceding 12-month period were enrolled.Ultrasound examinations were performed at gestational ages ranging from 11 to 14 weeks according to menstrual dates.The CRL of each fetus was measured three times,the mean of which was used to derive the best-fit fractional polynomial regression model for estimation of gestational age in relation to CRL.For each fetus,the menstrual age was compared to the gestational age calculated using six established dating formulae based on CRL measurement.The mean of the differences between estimated and menstrual age was calculated for each formula.3.The data were collected from pregnant women with singleton pregnancies in whom fetal ultrasound was performed and the fetal NT thickness was measured between 1+0 and 13+6 weeks of gestation.The relationship between NT and CRL was analyzed by regression method.The 5th,50th and 95th percentiles of NT thickness were calculated for corresponding CRL.The distribution of multiple of median(MoM)values of the NT thickness with crown-rump length(CRL)in 5-mm intervals and the 95 th percentile of MoM were calculated with the linear regression method.Results1.Of the 4710 subjects recruited,the mean and SD value of CRL were changed linearly with gestational age.The best-fit equation for the sonographic estimate of gestational age(GA,in days)from CRL(in mm)wasGA=59.361513+0.461425×CRL(R2=0.8028)2.The mean difference between menstrual age and the predicted gestational age was 0.22 days(95%CI,0.05 to 0.21),which was lower than that of the 6 established CRL dating formulae.3.The present study showed that NT measurements increase with increasing CRL and a false positive rate increases with increasing gestational age.NT was not related to gender.NT MoM value is normal distribution,and has no correlation with CRL.The 95th percentile for NT MoM is 1.45,which is convenient for clinical use.Conclusion1.We have derived a formula suitable for the dating of naturally conceived pregnancies between 11+0 and 13+6 weeks of gestation that has no systematic prediction error,comparing favorably with established CRL dating formulae.2.The present study offers normative data of the fetal NT thickness in a Chinese population,which can be used as reference for screening chromosomal aberrations or other congenital abnormalities in the first trimester.