Ultrasound measurement of fetal size in rural Guatemala.

OBJECTIVES: To describe the fetal growth pattern of a population from rural Guatemala and determine when during gestation growth faltering becomes evident. METHODS: Ultrasound examinations were conducted for 319 women. Femur length (FL), biparietal diameter (BPD), abdominal (AC) and head circumference (HC) were compared with reference values. RESULTS: FL and AC were similar to reference values throughout gestation. BPD and HC were below the 50th percentile by 30 weeks' gestation and below the 10th percentile later in gestation. We expected all four dimensions to show marked growth restriction during gestation. Measurement differences may explain the results but would call into question the value of cross-study comparisons. Infants born small for gestational age were small in all measures as early as 15 weeks. CONCLUSIONS: Fetal growth faltering begins in early gestation among infants who were born small. The lack of deviation from reference data for FL and AC requires further clarification.     

产前超声估测胎重多参数新回归方程及准确性比较

目的:创建新的适合于中国人的多参数回归公式用于胎重估测。方法:750例孕妇,在分娩前3d以内超声检查,记录胎儿双顶径(BPD)、头围(HC)、腹围(HC)和股骨长(FL),出生后记录新生儿体重。其中600例用于公式创建,采用非线性回归设计公式,另150例用于公式的验证。结果:Log10EFW=1.0163+0.0023(HC)+0.0603(AC)+0.2571(FL)+0.0011(BPD)(AC)-0.0074(AC)(FL)(R=0.846)。在验证组,新公式与其他常用公式相比,平均绝对误差及平均绝对百分误差均为最低,准确性较高。结论:新公式更适宜于评估中国胎儿体重。     

Ultrasound biometry of Arabian fetuses.

OBJECTIVE: To establish fetal ultrasound biometry charts for Arabian fetuses between 14 and 40 weeks of gestation. METHOD: Cross-sectional fetal ultrasound data of normal singleton pregnancies, which had been performed over a period of 7 years, were retrieved. Only pregnant Arab women with certain last menstrual period dates and/or early ultrasound examinations were included. Each fetus contributed to only one set of data. Normal ranges for biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL) were established. The mean and 5th and 95th percentiles at 18th, 28th, and 36 weeks of gestation were compared with similar ranges of published data from pregnancies of American and Anglo-Saxon population. RESULTS: Fetal ultrasound biometry has been established for our local population. Comparing our data with Western population emphasizes the presence of significant variation in fetal morphometric measurements, particularly in the later weeks of gestation and at the extremes of the range of fetal size. CONCLUSION: The clinical significance of this variation differs according to the primary objective of ultrasound fetal measurements. For estimation of fetal age, usually by head and femur measurements in early gestation, ethnic variation seems to have limited significance. Whereas for estimation of fetal growth and/or weight in the third trimester, based on abdominal circumference, the use of given points, e.g., 10th or 5th percentile derived from other population charts, has the potential of either over- or underdiagnosis of IUGR fetuses. The adoption of locally developed charts is recommended.     

Longitudinal reference charts for growth of the fetal head, abdomen and femur

OBJECTIVES: The aims of the present study were to establish improved reference charts for growth of the fetal head, abdomen and femur, and to determine the effect of fetal and maternal factors. STUDY DESIGN: This prospective longitudinal study included 650 low-risk pregnancies. Outer-outer biparietal diameter (BPD), head circumference (HC), mean abdominal diameter (MAD), abdominal circumference (AC) and femur length (FL) were measured by ultrasound, and the statistical analysis was based on regression analysis and multilevel modeling. RESULTS: Reference percentiles for the growth of MAD, AC and FL showed continuous growth in gestational week 10-40, while BPD and HC showed a slightly blunted growth toward the end of pregnancy. FL was the only variable that was not influenced by gender. There was a significant negative association between breech presentation and all five biometrical variables, while maternal weight was positively associated with all five variables. Cephalic index significantly influenced BPD and HC. Maternal height had a positive effect on BPD, HC, AC and FL, and parity had a positive effect on MAD and AC, while smoking influenced negatively HC, MAD, and FL. Terms for calculating conditional reference values and customisation for individualised growth assessment are presented. CONCLUSIONS: New reference charts for the growth of fetal head, abdomen and femur are suggested for assessing fetal size and growth, and can be adjusted for maternal and fetal factors to suite individual pregnancies.     

Fetal age assessment based on femur length at 10-25 weeks of gestation, and reference ranges for femur length to head circumference ratios

BACKGROUND: The aim of the present study is to establish new reference charts for gestational age assessment based on fetal femur length (FL), and new reference ranges for FL to head ratios at gestational weeks 10-25, and to determine the effect of maternal and fetal factors on these charts. METHODS: Six hundred fifty low-risk women with regular menstrual periods and singleton pregnancies were recruited to a prospective cross-sectional study after obtaining written consent. FL, outer-outer biparietal diameter (BPD), and head circumference (HC) were measured at 10-25 weeks of gestation. We used regression analysis in order to construct mean curves and to assess the effect of maternal and fetal factors on age assessment. RESULTS: The new chart for age assessment by means of FL was based on 636 measurements. The 95% CI of the mean corresponded to <1 day. The variation between the mean and the 90th percentile was 5, 6, and 7 days at 13, 18, and 23 weeks, respectively, similar to the results when using BPD or HC. Maternal age modestly influenced gestational age assessment (1.3 days/10 years, P = 0.005), whereas smoking, height, body mass index, multiparity, fetal sex, cephalic index, and breech presentation had no impact. Reference charts for FL to head ratios have been presented. Maternal age, fetal sex, and cephalic index influenced the FL/BPD ratio, whereas only fetal sex influenced FL/HC. CONCLUSIONS: Fetal age assessment based on FL is an equally robust method as using HC. FL/HC is a more robust ratio to characterize fetal proportions than is FL/BPD.     

Evidence That Normal Fetal Growth Can Be Noncontinuous

Fetal growth is presumed by current models to be continuous. We hypothesized that normal fetal growth is not continuous and that it demonstrates a pulsatile pattern. Fetal morphometric parameters were examined in 9 healthy women at an average interval of 2.7 days between 25 and 36 weeks gestation using an Acuson XP3 unit (Mountain View, CA) employing a 3.5 MHz curvilinear transducer. Parameters examined included biparietal diameter (BPD), abdominal circumference (AC), femur length (FL), and humeral length (HL). Mothers had normal prepregnancy weight, were nonsmokers, had normal glucose tolerance screening, and were without medical complications. Mean maternal age was 28.7 ± 5.8 years (S.D.) and mean maternal weight gain was 16.8 ± 3.3 kg. All neonates were born at term (range 39–42 weeks), without anomalies and a mean percentile birth weight at the 53rd centile (range 20–95th). Wald-Wolfowitz runs test was used to test for nonrandom patterns in the residuals from the fitted regression curve. When modeled by second order regression equations, 4/9 AGs and 3/9 BPDs demonstrated significant nonrandom patterns in the residuals (P < 0.05 Wald-Wolfowitz runs test) from the fitted curve consistent with pulsatile growth. In addition, prolonged periods without detectable growth (<2.0 mm) were observed for both AC (up to 28 days) and BPD (up to 25 days). All parameters demonstrated no measurable growth in a majority of fetuses (BPD 5/9, AC 7/9, FL 5/9, HL 7/9) for at least a single 2 week interval. In conclusion, in this data set BPD and AC demonstrated significant noncontinuous growth in several fetuses suggestive of pulsatility. Prolonged periods (≥2 weeks) without measurable growth were detected for all parameters in most fetuses. These findings support the hypothesis that fetal growth can be noncontinuous under normal conditions.     

Reference charts and equations of Korean fetal biometry

OBJECTIVE: To construct new reference charts and equations for fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur diaphysis length (FDL) from Korean fetuses at 12-40 weeks. METHOD: Prospective cross-sectional data obtained in one center for 5 years from a population of pregnant women undergoing ultrasound examination between the 12th and 40th week of gestation. Exclusion criteria comprised all maternal and fetal conditions possibly affecting fetal biometry. No fetuses were excluded on the basis of abnormal biometry. For each measurement, regression models were fitted to estimate both the mean and the standard deviation at each menstrual age. RESULTS: Biometric measurements were obtained for 10 455 fetuses. New charts and reference equations are reported for BPD, HC, AC and FDL. Reference equations are cubic models. CONCLUSION: We present new Korean reference charts and equations for fetal biometry. They can be easily used in obstetric ultrasound studies for the Korean population.     

孕晚期营养素摄入与B超下胎儿各生长指标的关系

目的:探讨妊娠晚期孕妇不同营养素摄入量与B超下胎儿各部位测量值的关系。方法:对799例无妊娠合并症及并发症的健康孕妇进行前瞻性营养调查,在妊娠32、34、36周调查3天。用食物日志形式记录3天摄入食物的种类及重量。将食物摄入量转换成营养素摄入量。于妊娠28周及38周左右行两次B超检查,测量胎儿双顶径、头围、腹围、股骨及肱骨长度,并用两次测量之差值反映胎儿孕晚期的生长情况。采用多元线性回归分析孕晚期营养与胎儿生长的关系。结果:孕晚期脂肪供能比与胎儿腹围、头围和股骨增长有关,脂肪供能比每增加1%,胎儿腹围增加2.27mm(P=0.023),胎儿头围增加3.86mm(P=0.01),胎儿股骨长度增加1.35mm(P=0.04)。钙的摄入量与胎儿股骨增长有关;锌、维生素B1、、B2及维生素E与胎儿双顶径关系密切。结论:脂肪供能比与胎儿多个生长指标密切相关,是影响胎儿出生体重的重要因素。不同的营养素对B超测量的胎儿生长指标的影响不完全相同的。     

Fetal biometry: does patient ethnicity matter?

Abstract

Objective: To determine if fetal biometry varies according to race.

Methods: We performed a retrospective chart review of prenatal ultrasounds completed in our Perinatal Center from January 2009 to December 2010. Singleton pregnancies 17 to 22.9 weeks were included. Pregnancies complicated by IUGR, fetal anomalies, chronic maternal diseases, or dated by an ultrasound after the first trimester were excluded. Biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and humerus length (HL) were compared between African Americans (AA), Caucasians, and Hispanics using ANOVA and Student t-test.

Results: Included were 1327 AA, 147 Caucasian, and 86 Hispanic subjects. The AC was significantly smaller in AA than Caucasians (p?=?0.008). There was no difference between AA and Caucasians in BPD, HC, FL, or HL. There were no differences between Hispanics and either Caucasians or AA in any of the biometries evaluated.

Conclusions: A single fetal growth curve is not applicable across all ethnicities. AA fetuses have smaller AC then Caucasian fetuses from 17 to 22.9 weeks, which is typically the period when anatomic surveys are performed. Because AC contributes heavily to estimated fetal weight calculations, physicians may be over estimating growth restriction in AA patients. Ethnicity-specific fetal growth curves are indicated to limit unnecessary follow up.     

Ultrasonic estimation of fetal weight at term: an evaluation of eight formulae

AIM: To compare the accuracy of eight sonographic formulae for predicting fetal birth weight at term in a multiethnic population. METHODS: Pregnant women at term who were booked for induction of labor or elective cesarean section were included in the study. Eight ultrasonic fetal biometric formulae were used to predict fetal birth weight. RESULTS: A total of 173 patients were included in the study; 53 (30.6%) patients were from the Indian subcontinent, 44 (25.4%) patients were from Africa, 33 (19.1%) patients were from the Arabian Peninsula and 43 (24.9%) were from other ethnic groups. The mean absolute error ranged from a minimum of 0.3% (+/-11.3) for Hadlock (biparietal diameter [BPD], head circumference [HC], abdominal circumference [AC], femur length [FL]) to a maximum of 37.5% (+/-10.0) for Warsof (FL). The correlation of estimated fetal weight with actual birth weight ranged from a minimum of 0.09 with Warsof (FL) to a maximum of 0.77 with Shepard and Warsof (BPD, AC) and Hadlock (BPD, HC, AC, FL). The combination of AC with BPD measurements rather than FL achieves a high level of accuracy. CONCLUSIONS: Shepard (BPD, AC) provides a simple and accurate logarithm for the prediction of fetal weight at term in the studied multiethnic population.     

Accuracy of single ultrasound parameters in detection of fetal growth restriction

The objective of this study was to evaluate the diagnostic accuracy of different single ultrasonographic parameters in predicting intrauterine growth-restricted (IUGR) babies as defined by Ponderal index at birth. Study sample composed of two sets of data from Iran and Australia. The Iranian sample consisted of 296 Iranian women. All the study women received prenatal care and delivered at Fatemieh Hospital in Shahrood, Iran. The data from 219 Australian fetuses were obtained from the ultrasound section at the Wollongong Hospital in Australia. Ultrasonographic measurements of biparietal diameter (BPD), femur length (FL), head circumference (HC), abdominal circumference (AC), amniotic fluid index (AFI), and Doppler from umbilical arteries (S/D ratio) were obtained. Only those pregnancies were included in which the estimated date of delivery (EDD) by LMP (last menstrual period) agreed within 14 days with the estimated date of delivery determined by the initial ultrasound examination. Sensitivity (SE), specificity (SP), positive predictive value (PPV) and negative predictive value (NPV) were calculated for single proposed ultrasound parameters in the Iranian and Australian samples. When different variables are compared, with a cut-off point at or below the 10th percentile AC and HC had the highest sensitivities in the Australian sample while AC was the most sensitive parameter for IUGR detection in the Iranian sample. BPD has a reasonably high sensitivity at this threshold. The AFI ratio has the lowest sensitivity in predicting IUGR in the Australian sample. Positive predictive values were low in all of the parameters in both the Iranian and Australian samples. By increasing the cut-off for PI to the 20th percentile, the sensitivity of reduced AC increased in the Australian sample while the sensitivity for an abnormal S/D ratio and reduced AFI to identify IUGR decreased. Our results indicate that reduced AC was the best single parameter in discriminating between IUGR and non-IUGR fetuses with the highest sensitivity among the proposed parameters in the both Iranian and Australian sample. However, the PPV of this parameter is low. This means that a high number of false-positive cases are detected using each parameter, which reduces the usefulness of identification. Other ultrasound obstetrical parameters may also have a reasonable level of sensitivity, however, the PPV of all parameters is low. On the whole, our results show that although the examined ultrasonographic criteria may detect a group of fetuses that need close antepartum surveillance, none of these parameters are appropriate enough to be used in isolation in clinical practice. Using single ultrasound parameters does not have high sensitivity and PPVs in detection of fetal growth restriction. This limits accuracy and utility of these tests in the detection of IUGR fetuses.     

The effect of fetal sex on customized fetal growth charts

Objective: To evaluate the effect of fetal sex on singleton pregnancy growth charts customized for parental characteristics, race, and parity

Methods: In a multicentric cross-sectional study, 8070 ultrasonographic examinations from low-risk singleton pregnancies between 16 and 40 weeks of gestation were considered. The fetal measurements obtained were biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL). Quantile regression was used to examine the impact of fetal sex across the biometric percentiles of the fetal measurements considered together with parents’ height, weight, parity, and race.

Results: Fetal gender resulted to be a significant covariate for BDP, HC, and AC with higher values for male fetuses (p?≤?0.0009). Minimal differences were found among sexes for FL. Parity, maternal race, paternal height and maternal height, and weight resulted significantly related to the fetal biometric parameters considered independently from fetal gender.

Conclusion: In this study, we constructed customized biometric growth charts for fetal sex, parental, and obstetrical characteristics using quantile regression. The use of gender-specific charts offers the advantage to define individualized normal ranges of fetal biometric parameters at each specific centile. This approach may improve the antenatal identification of abnormal fetal growth.     

Clinical validation of two equations in antenatal prediction of Chinese fetal weight by ultrasonography.

The purpose of this series is to prospectively validate the Chinese equations for predicting fetal weight developed in a previous study. A total of 640 Chinese fetuses were examined antenatally for biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) by real-time ultrasonography within two days of delivery. The results showed the actual birth weight (BW) to be highly correlated with the estimated body weight for both the equation using BPD and AC (EBW1) (r = 0.888, p less than 0.0001) and the equation using BPD, AC and FL (EBW2) (r = 0.890, p less than 0.0001). Our results demonstrate that the Chinese equations developed by Hsieh et al are a better fit for Chinese fetuses than the foreign equations are. Also, the two Chinese equations predict fetal weight well between 2,000 g and 4,000 g, but further modification is needed in cases where the BW is less than 2,000 g or greater than 4,000 g.     

Improving customized fetal biometry by longitudinal modelling

Objective: To develop customized biometric charts to better define abnormal fetal growth.

Methods: A total of 1056 singleton fetuses from the Raine Study underwent serial ultrasound biometry (abdominal circumference [AC], head circumference, and femur length) at 18, 24, 28, 34, and 38 weeks’ gestation. Customized biometry trajectories were developed adjusting for epidemiological influences upon fetal biometry using covariates available at 18 weeks gestation. Prediction accuracy (areas under the receiver operating characteristic curve [AUC] and 95% confidence interval [95%CI]) was evaluated by repeated random sub-sampling cross-validation methodology.

Results: The model for derived estimated fetal weight (EFW) performed well for EFW less than 10th predicted percentile (AUC?=?0.695, 95%CI, 0.692–0.699) and EFW greater than 90th predicted percentile (AUC?=?0.705, 95%CI, 0.702–0.708). Fetal AC was also well predicted for growth restriction (AUC?=?0.789, 95%CI, 0.784–0.794) and macrosomia (AUC?=?0.796, 95%CI, 0.793–0.799). Population-derived, sex-specific charts misclassified 7.9% of small fetuses and 10.7% of large fetuses as normal. Conversely, 9.2% of those classified as abnormally grown by population-derived charts were considered normal by customized charts, potentially leading to complications of unnecessary intervention.

Conclusions: Customized fetal biometric charts may offer improved ability for clinicians to detect deviations from optimal fetal growth and influence pregnancy management.     

Antenatal care in The Gambia: Missed opportunity for information, education and communication

Background

Conventionally, the pregnancy duration is accepted to be 280–282 days. Fetuses determined by ultrasound biometry to be small in early pregnancy, have an increased risk of premature birth. We speculate that the higher rate of preterm delivery in such small fetuses represents a pathological outcome not applicable to physiological pregnancies. Here we test the hypothesis that in low-risk pregnancies fetal growth (expressed by fetal size in the second trimester) is itself a determinant for pregnancy duration with the slower growing fetuses having a longer pregnancy.

Methods

We analysed duration of gestation data for 541 women who had a spontaneous delivery having previously been recruited to a cross-sectional study of 650 low-risk pregnancies. All had a regular menses and a known date of their last menstrual period (LMP). Subjects were examined using ultrasound to determine fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) at 10–24 weeks of gestation. Length of the pregnancy was calculated from LMP, and birth weights were noted. The effect of fetal size at 10–24 weeks of gestation on pregnancy duration was assessed also when adjusting for the difference between LMP and ultrasound based fetal age.

Results

Small fetuses (z-score -2.5) at second trimester ultrasound scan had lower birth weights (p < 0.0001) and longer duration of pregnancy (p < 0.0001) than large fetuses (z-score +2.5): 289.6 days (95%CI 288.0 to 291.1) vs. 276.1 (95%CI 273.6 to 278.4) for HC, 289.0 days (95%CI 287.4 to 290.6) vs. 276.9 days (95%CI 274.4 to 279.2) for AC and 288.3 vs. 277.9 days (95%CI 275.6 to 280.1) for FL. Controlling for the difference between LMP and ultrasound dating (using HC measurement), the effect of fetal size on pregnancy length was reduced to half but was still present for AC and FL (comparing z-score -2.5 with +2.5, 286.6 vs. 280.2 days, p = 0.004, and 286.0 vs. 280.9, p = 0.008, respectively).

Conclusion

Fetal size in the second trimester is a determinant of birth weight and pregnancy duration, small fetuses having lower birth weights and longer pregnancies (up to 13 days compared with large fetuses). Our results support a concept of individually assigned pregnancy duration according to growth rates rather than imposing a standard of 280–282 days on all pregnancies.     

The use of three-dimensional ultrasound does not improve training in fetal biometric measurements

Objective.?To investigate whether three-dimensional (3D) technology offers any advantage over two-dimensional (2D) ultrasound in fetal biometric measurement training.

Methods.?Ten midwives with no hands-on experience in ultrasound were randomized to receive training on 2D or 3D ultrasound fetal biometry assessment. Midwives were taught how to obtain fetal biometric measurements (biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), and femur length (FL)) by a trainer. Subsequently, each midwife measured the parameters on another 10 fetuses. The same set of measurements was repeated by the trainer. The percentage deviation between the midwives' and the trainer's measurements was determined and compared between training groups. Time required for completion was recorded. Frozen images were reviewed by another sonographer to assess the image quality using a standardized scoring system.

Results.?The median time for the complete set of measurements was significantly shorter in the 2D than in 3D group (13.4?min versus 17.8?min, P?=?0.03). The mean percentage deviations did not reach statistical significance between the two groups except for FL (3.83% in 2D group versus 2.23% in 3D group (P?=?0.046)). There were no significant differences in the quality scores.

Conclusions.?This study showed that the only demonstrable advantage of 3D ultrasound was a slightly more accurate measurement of FL, at the expense of a significantly longer time required.     

Value of a single early third trimester fetal biometry for the prediction of birth weight deviations in a low risk population

OBJECTIVE: To analyze the value of a single ultrasound biometry examination at the onset of the third trimester of pregnancy for the detection of small-for-gestational-age (SGA) and large-for-gestational-age (LGA) at birth in a low risk population. The aim of this study was to develop a simple and useful method for the detection of growth deviations during pregnancy in primary care (midwife or general practitioner) practices. SETTING: A Dutch primary care midwifery practice. STUDY DESIGN: In an earlier study, we developed parity and sex specific fetal growth charts of abdominal circumference (AC) and head circumference (HC) on the basis of ultrasound data of a low-risk midwifery population in the Netherlands. In the present study, we calculated sensitivity, specificity and predictive values at different cut-off points of AC and HC for the prediction of growth deviations at birth. Patients booked for perinatal care between 1 January 1993 and 31 December 2003 (n=3449) were used for the identification of cut-off points (derivation cohort) and those admitted between 1 January 2004 and 31 December 2005 (n=725) were used to evaluate the performance of these cut-offs in an independent population (validation cohort). For the determination of SGA and macrosomia at birth, we used the recently published Dutch birth weight percentiles. RESULTS: Most promising cut-offs were AC or=75(th) percentile for the prediction of macrosomia (birth weight >or=90(th) percentile). Within the validation cohort these cut-offs performed slightly better than in the derivation cohort. For the prediction of SGA, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were 53% (95% CI 49-58%), 81% (95% CI 80-83%), 26% (95% CI 23-29%), and 93% (95% CI 93-94%), respectively. The false positive rate was 74%. For the prediction of macrosomia, the values of these parameters were 64% (95% CI 59-69%), 80% (95% CI 78-81%), 23% (95% CI 20-26%), and 96% (95% CI 95-97%), respectively. Here, false positive rate was 77%. No cut-offs were found that predicted extreme birth weight deviations (or=97.7 percentile) sufficiently well. CONCLUSIONS: In a low risk population, we could predict future growth deviations with a higher sensitivity and in a significant earlier stage (at the onset of the third trimester of pregnancy) than with the use of conventional screening methods (i.e., palpation of the uterus only and fundus-symphysis measurement). Sonographic measurement of fetal abdominal circumference enables to detect more than half of cases of SGA at birth and more than two-thirds of cases of macrosomia with acceptable false-positive rates. We suggest that fetuses with biometry results below the 25(th) percentile or above the 75(th) percentile at the onset of the third trimester of pregnancy should be more intensively investigated in order to distinguish between pathology (e.g., IUGR or macrosomia) and physiology and to decide about the appropriate level of further perinatal care.     

B型超声测量胎儿股骨皮下组织厚度预测胎儿体重

目的探讨应用Ｂ型超声测量胎儿股骨皮下组织厚度预测胎儿出生体重的临床价值。方法应用Ｂ型超声对１７８例胎儿的双顶径、头围、腹围、股骨长、股骨皮下组织厚度进行测量并与新生儿出生体重的关系进行分析。结果股骨皮下组织厚度与新生儿出生体重相关性最好（ｒ＝０．８６０１）,对巨大儿诊断的敏感性为９１％,特异性为９４％,胎儿股骨皮下组织厚度与孕周呈正相关（ｒ＝０．７０７０）。结论应用Ｂ型超声测量胎儿股骨皮下组织厚度预测胎儿出生体重,方法简单、准确,有较好的临床应用价值。     

B超测量胎儿肝脏面积预测巨大儿的临床价值

目的 :研究应用B型超声测量胎儿肝脏面积预测巨大儿的临床价值。方法 :应用B型超声测量 36 0例足月妊娠胎儿的双顶径、头围、腹围、股骨长度、股骨皮下组织厚度、肝脏长度和肝脏面积 ,并分析各预测指标与新生儿出生体重的关系及用于预测巨大儿的敏感性和特异性。结果 :各项预测指标中胎儿肝脏面积与新生儿体重的相关性最好 (r =0 .80 6 ) ,对巨大儿诊断的敏感性为 88 89% ,特异性为 95 4 2 %。结论 :应用B型超声测量胎儿肝脏面积预测巨大儿的准确性较高 ,具有临床应用价值