B超测量胎儿腹围预测胎儿体重的价值

目的 研究B超测量胎儿腹围预测巨大胎儿的临床价值。方法 选择184例宫高＋腹围≥140cm的足月单胎孕妇，应用B超测量胎儿双顶径（BPD），头围（HC）腹围（AC），股骨长度（FL）；根据新生儿体重将孕妇分为巨大儿组及非巨大儿组，比较两组间差异；分析腹围与新生儿体重的关系。结果 胎儿腹围与新生儿体重的相关性最好（r=0.84），当胎儿腹围≥35.0cm时，可以预测85.7%的巨大胎儿。结论 超声测量胎儿腹围能准确预测巨大胎儿的体重。     

超声生物学指标预测胎儿出生时体重的价值

目的应用超声检测胎儿多项生物学指标,预测胎儿出生时体重。方法超声检测293例晚孕胎儿双顶径、头围、腹围、股骨径,分析其与胎儿出生时体重的关系。结果单指标腹围、双顶径、股骨径、头围与新生儿出生体重均呈正相关,其中腹围与出生体重相关性最好,双顶径及股骨长次之;拟和四个自变量,均选入方程,其复相关系数为0．890（P〈0．001）。其中腹围引入回归方程预测293例中胎儿体重,绝对误差值〈±250g的257例,占87．7％,平均相对误差为4．4％。腹围对非巨大儿体重的胎儿诊断敏感性为99．6％,正确率为95．6％。结论腹围预测胎儿出生体重,方法简单准确,具有较好的临床实用价值。     

用三维超声估计胎儿体重

准确预测出生体重对现代产科工作来说十分重要。不少报道用二维超声的不同参数估计胎儿体重[1-5],其中双顶径、腹围、及股骨长度是最常用的组合,但估计的出生体重与实际体重相差可达20%,因此,我们希望三维技术能提供更准确的出生体重预报。一、用胎儿容积估计胎儿体重的历史198     

超声测量胎儿腹围预测巨大儿的可行性研究

目的 探讨超声测量胎儿腹围预测巨大儿的可行性。方法 对1077名孕龄在36周以上、单胎、且产前7天内进行过超声检查的资料回顾性研究。以胎儿腹围的超声测值评价预测巨大儿的价值。结果 有394例胎儿腹围大于等于35厘米，其中68例出生体重大于等于4000克。在鉴别巨大儿方面，其敏感性为93、15％，特异性为67．53％；有23例胎儿腹围大于等于38厘米，其中21例出生体重大于等于4000克，如以38厘米腹围为标准，则敏感性为28．77％，特异性为99．80％。结论 超声测量胎儿腹围可鉴别巨大儿．了解胎儿腹围测量的两个界值(35CM，38CM)有助于临床医生避免或处理如肩难产等与巨大儿相关的产科问题。     

超声胎儿测量系统预测胎儿体重的临床价值

目的探讨超声胎儿测量系统预测胎儿体重的临床应用价值。方法应用超声对450例足月胎儿进行双顶径（BPD）、股骨长度（FL）、腹前后径（APTD）、腹横径（TTD）的测量,由超声诊断仪自带公式计算出所估计的体重,把预测体重和实际出生体重进行对比分析,并依据性别和新生儿体重进行分组对比分析。结果超声预测胎儿体重与实际出生体重符合者374例,符合率83．1％。体重预测的准确性与胎儿性别和新生儿体重无明显关系。结论本文使用超声测量双顶径等四项指标能更准确的估测胎儿体重,既克服了单一参数的片面性,又避免了更多指标测量的繁琐,不失为一种客观、准确、科学、简便,可重复的方9法,可以更好的服务与应用于临床。     

一种便于实际应用的超声多指标估计胎儿体重方法

本文对232例胎儿的双顶径、腹径、股骨长度和股径进行了超声测定,将这些数据作统计分析后导出3个估计胎儿体重回归方程。其中四元方程为最佳方程,其复相关系数R=0.9821,剩余准标差S=113.8。经过对50例孕妇的初步验证,结果是令人满意的。本文推荐的多元方程简单而较准确,有利于制成表格,便于临床应用。     

B超测量胎儿肝脏长度和腹围预测胎儿体重的价值

目的研究B超测量胎儿肝脏长度和腹围预测巨大胎儿的临床价值.方法选择169例宫高 腹围≥140 cm的足月单胎孕妇,应用B超测量胎儿双顶径(BPD)、头围(HC)、腹围(AC)、股骨长度(FL)、肝脏长度(FLL)和肱骨软组织厚度(HSTT),分析与新生儿体重的关系.结果胎儿FLL与新生儿体重的相关性最好(r＝ 0.86,P＜0.01),其次为AC(r＝ 0.83,P＜ 0.01).结论超声测量胎儿FLL和AC能准确预测巨大胎儿的体重.     

超声估计胎儿体重的方法探讨

预测胎儿体重是产前监护的一项重要内容之一,胎儿体重与胎儿成熟度之间有十分平行的关系.临床应用腹部触诊及宫底高度的测量来估计胎儿体重虽然是一种简单易行的办法,但是由于受到腹壁厚度、子宫张力、羊水量、胎位等多种因素的影响,这种方法估计胎儿体重不够精确,只能作为临床筛选应用.     

孕妇腹壁脂肪厚度对胎儿体重估计的影响

为了较准确地估计胎儿体重 ,对 2 70例孕妇的腹壁脂肪厚度用皮褶计进行了测量 ,并总结出胎儿体重估计的改良公式 :胎儿体重(g) =(宫高 -腹脂厚度 )×(腹围 -腹脂厚度 ) 2 0 0 ,经与常用的公式 :胎儿体重(g) =宫高×腹围 2 0 0比较 ,结果显示 :孕妇的腹脂厚度≥ 3cm时 ,运用改良公式估计胎儿体重符合率为6 3 .9% ,两组相比差异显著(P <0 .0 1)。孕妇的腹脂厚度 <3cm时 ,运用两公式估计胎儿体重无差异 (P <0 .5 )。提出 :对于腹脂厚度≥ 3cm的孕妇 ,应采用改良公式估计胎儿体重     

Estimation of fetal weight by ultrasound

Birth weight (BW) and log10 birth weight (LBW) are expressed as linear, multilinear, parabolic, and polynomial regression functions of the abdominal circumference (AC), and combinations of fetal index measurements, namely, AC and head circumference (HC); biparietal diameter (BPD) and AC; and BPD, HC, and AC. The relationship of somatic weight and log10 somatic weight to AC was similarly determined. The analysis generated 20 equations whose accuracy in providing BW estimates is compared. Several equations provide BW estimates whose mean percentage deviations from measured BWs do not differ significantly. The deviations, however, have the smallest variance when BW is estimated from the HC and AC either by using a multilinear regression equation or by deriving separate estimates of brain and somatic weights from these index measurements. The role of individual and population differences in fetal anthropometry as causes of error in estimating BW by different methods is discussed. Because HC is a function of both BPD and occipito-frontal diameter (OFD), it is a better brain-size modulus than the commonly used BPD and avoids the errors of underestimation which occur when the BPD is unusually small in cases of dolichocephaly. A comparison of ponderal growth in American and South African fetal populations shows differences throughout most of the gestational range (26-40 wk) analyzed in this study.     

Caveats in the monitoring of fetal growth using ultrasound estimated fetal weight

IntroductionUltrasound estimated fetal weight is increasingly being used in the monitoring of fetal growth. Differences between estimated fetal weight formulae, curves and measurement methods could lead to significant differences in results. The aim of this study was to investigate the potential impact of these differences on estimated fetal weight and its use in monitoring fetal growth, both by modelling and by analysis of ultrasound scan data.MethodsFour estimated fetal weight curves were compared in their original form and also normalised to term weight. Estimated fetal weight was calculated from 50th centiles of widely used charts of abdominal and head circumference and femur length and plotted on a widely used estimated fetal weight curve. Fetal measurement data were used to assess the impact of fetal proportions on estimated fetal weight error and on growth trajectory when different estimated fetal weight formulae are used.ResultsEstimated fetal weight curves differ significantly, but after normalisation there is closer agreement. Estimated fetal weight modelled using modern measurement methods differs from the widely used estimated fetal weight growth curve. Errors in estimated fetal weight are correlated with differences in fetal proportions and this can lead to significant changes in estimated fetal weight growth trajectory if different estimated fetal weight formulae are used.ConclusionsChoice of measurement methods, estimated fetal weight formulae and growth curves have a significant effect on estimated fetal weight growth trajectories relative to normal ranges. It is important to understand these caveats when using estimated fetal weight to monitor fetal growth.     

Influence of fetal growth patterns on sonographic estimation of fetal weight

Six published fetal weight estimating regression models proposed for clinical use were evaluated in 259 pregnant women who delivered within 72 h of an ultrasound evaluation performed with sector scanner. The patient sample included 89 (33.2%) fetal weights that were below the 10th or above the 90th percentile for menstrual age. The actual mean percent error (systematic error), standard deviation (random error), and the number of large errors of prediction for all equations were greatest in fetuses that were small- and large-for-gestational age. Whereas there were no significant differences between equations for the patient sample as a whole, equation AC,BPD (Shepard) had the smallest systematic error in intrauterine growth retarded, premature, and normal-term fetuses less than 4000 g. Conversely, the systematic error of the models that included femur length was smallest at the upper end of the weight scale and in macrosomic fetuses in general. In that regard, the accuracy of fetal weight prediction could be increased by selecting the appropriate model for the proper clinical indications. Although these findings can be explained by the limitations of the current regression models in estimating fetal soft tissue mass, a subtle effect of the use of the sector scanner on the results of this study cannot be completely excluded and requires further investigation.     

Evaluation of three methods for estimating fetal weight

Three ultrasonic methods for estimating fetal weight (Campbell, Warsof, and Shepard) were compared in 124 singleton pregnancies. Fetal abdominal circumference was obtained by use of a map measurer and from diameter measurements and the equation for the circumference of a circle. Campbell's formula for estimating fetal weight was superior between 2,000 and 4,000 g, whereas Shepard's method was slightly better below 2,000 g and over 4,000 g. Hence, varied fetal anthropometric characteristics make it mandatory that several methods be evaluated by each institution before one is selected. With the methods of Campbell and Shepard, use of diameter measurements and the equation for the circumference of a circle resulted in a more accurate estimated fetal weight than when a map measurer was used.     

利用上臂周径等多项测值预测胎儿体重的初步研究

目的探讨利用上臂周径等预测胎儿体重的临床价值。方法2001年5月-2004年6月，我院分娩的369例孕妇于分娩前48小时应用B型超声对其胎儿测量上臂周径(ARC)、双顶径(BPD)、腹径(AD)、腹围(AC)、股骨长度(FL)、肱骨长度(HL)等，将其中160例作多元线性回归方程分析，得出估计胎儿体重的四元线形回归方程公式：将另209例所得数据代入上述公式并将预测的胎儿体重与实际出生体重比较，分析其误差；同时将该误差与套用Favre等建立的用三维技术测量肢体周径估计胎儿体重的公式所得之误差进行比较。结果用本组公式预测胎儿体重与实际出生体重比较，绝对误差值≤100g的有70例，占33．5％，绝对误差值≤200g的有129例占61．7％；相对误差≤5％占58．0％，相对误差≤10％占88．1％。优于简单套用Favre等的三维技术测量肢体周径估计胎儿体重的方法。结论利用B型超声测量胎儿上臂周径预测胎儿体重，具有一定的临床实用价值。     

The management of error in ultrasound fetal growth monitoring

It is important to understand the uncertainty in fetal measurements when using them in the management of pregnancy. The aim of this essay is to provide background on errors and uncertainty, describing error sources and their potential impact, with guidance on improving accuracy. Errors can be systematic or random, arising from equipment, image plane selection, measurement method and caliper placement and influenced by image quality, training and experience. The uncertainty in measurements is larger than clinically significant differences in fetal size and growth. Errors can be reduced by implementing equipment acceptance testing, written procedures, training and audit.     

Ultrasonic estimation of fetal weight: a new predictive model incorporating femur length for the low-birth-weight fetus

Ultrasonic measurements of biparietal diameter, head circumference, abdominal circumference, and femur length were made in 50 preterm fetuses within 48 h of delivery. Measurements of femur length in addition to fetal head and abdomen significantly improved fetal weight prediction. A computer-derived formula incorporating femur length as an index of total fetal length was derived. This predicted 84% of weights within 10% of the birth weight. Comparisons with other formulas are given.     

超声诊断胎儿肢体畸形的价值

目的探讨胎儿肢体畸形的二维超声图像特征。方法回顾性分析11例胎儿肢体畸形的二维超声检查结果和图像特征,并与产后及引产后的结果对照。结果超声明确诊断7例胎儿肢体畸形,漏诊4例。结论典型胎儿肢体畸形有二维图像特征,末端指趾易漏诊,因超声无创伤、安全,可反复检查,是诊断胎儿肢体畸形的首选方法。     

Ultrasonographic assessment of growth and estimation of birthweight in late gestation fetal sheep

Our aim was to identify which ultrasound parameters can be most accurately measured and best predict ovine fetal weight in late gestation. Singleton pregnancies were established using embryo transfer in 32 adolescent ewes, which were subsequently overnourished to produce fetuses of variable size (1720–6260 g). Ultrasound measurements at 126–133 days gestation were compared with fetal weight/biometry at late-gestation necropsy (n = 19) or term delivery (n = 13). Abdominal circumference (AC) and renal volume (RV) correlated best with physical measurements (r = 0.78–0.83) and necropsy/birth weight (r = 0.79–0.84). Combination of AC + RV produced an estimated fetal weight equation [Log EFW = 2.115 + 0.003 AC + 0.12 RV – 0.005 RV²] with highest adjusted R² (0.72) and lowest mean absolute/percentage prediction error (396–550 g/11.1%–13.2%). In conclusion, AC and RV are parameters of choice for assessment of late-gestation ovine fetal growth and can be used to estimate fetal weight with similar accuracy to human fetuses.     

Menstrual age-dependent systematic error in sonographic fetal weight estimation: a mathematical model

PURPOSE: We used computer modeling techniques to evaluate the accuracy of different types of sonographic formulas for estimating fetal weight across the full range of clinically important menstrual ages. METHODS: Input data for the computer modeling techniques were derived from published British standards for normal distributions of sonographic biometric growth parameters and their correlation coefficients; these standards had been derived from fetal populations whose ages were determined using sonography. The accuracy of each of 10 formulas for estimating fetal weight was calculated by comparing the weight estimates obtained with these formulas in simulated populations with the weight estimates expected from birth weight data, from 24 weeks' menstrual age to term. Preterm weights were estimated by interpolation from term birth weights using sonographic growth curves. With an ideal formula, the median weight estimates at term should not differ from the population birth weight median. RESULTS: The simulated output sonographic values closely matched those of the original population. The accuracy of the fetal weight estimation differed by menstrual age and between various formulas. Most methods tended to overestimate fetal weight at term. Shepard's formula progressively overestimated weights from about 2% at 32 weeks to more than 15% at term. The accuracy of Combs's and Shinozuka's volumetric formulas varied least by menstrual age. Hadlock's formula underestimated preterm fetal weight by up to 7% and overestimated fetal weight at term by up to 5%. CONCLUSIONS: The accuracy of sonographic fetal weight estimation based on volumetric formulas is more consistent across menstrual ages than are other methods.