Foot length in fetuses with abnormal growth.

Sonographic fetal foot length is highly predictive of gestational age. In order to assess the reliability of this parameter in predicting gestational age in cases of abnormal fetal growth, we examined fetal foot length in small- and large-for-gestational-age fetuses. A nomogram of foot length versus gestational age between 15 and 37 weeks was constructed using cross-sectional data obtained from 5372 singleton fetuses. Fetal foot lengths for small-for-gestational-age fetuses (estimated fetal weight below the 10th percentile) and large-for-gestational-age fetuses (above the >90th percentile) fetuses were plotted against the foot length nomogram in order to determine the number of small-for-gestational-age fetuses and large-for-gestational-age fetuses with foot lengths below the 10th and above the 90th percentiles, respectively. Of the 586 small-for-gestational-age fetuses, 355 (60.6%) had foot lengths below the 10th percentile on the nomogram. When foot lengths from large-for-gestational-age fetuses were plotted on the foot length nomogram, 29.4% (219 of 744) had measurements above the 90th percentile. Fetal foot length can be influenced by growth restriction as well as states of accelerated fetal growth. Our findings imply that there are limitations to the use of fetal foot length for gestational age assessment, particularly in fetuses with growth abnormalities.     

The development of the fetal penis--an in utero sonographic evaluation.

OBJECTIVE: To establish a nomogram for fetal penile length during gestation. DESIGN: A prospective, cross-sectional study of normal singleton pregnancies. SUBJECTS: Four hundred and nineteen male fetuses between 14 and 38 weeks were studied. METHODS: Measurements of fetal penis length were performed by high resolution transvaginal ultrasonography between 14 and 17 weeks of gestation, and by transabdominal ultrasonography beyond 18 weeks of gestation. RESULTS: Adequate penile length measurements were obtained in all 419 fetuses. Penile length as a function of gestational age was expressed by the regression equation: (square root) penile length (mm) = 0.277 + 0.121 x gestational age (weeks). The correlation coefficient, r = 0.967 was found to be highly statistically significant (P < 0.0001). The normal mean and the 90% prediction limits were defined. During the study period, we identified three fetuses with abnormalities involving penile development. Using the above reference data range, it has been shown that their penile length was below the lower limit. CONCLUSIONS: The present data provide a normal range of fetal penile length from early stages of gestation that may allow intrauterine assessment of the development of the male external genitalia.     

正常胎儿主肺动脉多普勒参数与孕周的关系

目的探讨正常胎儿妊娠中、晚期主肺动脉多普勒参数与孕周的关系。 方法将孕龄为21~40周的正常胎儿300例按照孕龄分为10组,分别为21~22^＋6周、23~24^＋6周、25~26^＋6周、27~28^＋6周、29~30^＋6、31~32^＋6周、33~34^＋6周、35~36^＋6周、37~38^＋6周和39~40^＋6周,每组30例。采用彩色超声仪测量收集正常胎儿主肺动脉多普勒参数：收缩期加速度时间（AT）、射血时间（ET）、收缩期峰值流速（PSV）、舒张期末流速（EDV）、平均流速（MV）、搏动指数（PI）和阻力指数（RI）。建立不同孕周主肺动脉多普勒参数的正常参考值,对各参数值和孕周进行相关和回归分析。 结果300例胎儿均获得满意的主肺动脉流速曲线,AT、AT/ET、PSV、EDV和MV与孕周呈线性正相关（r=0.866、0.848、0.457、0.242、0.506,P均<0.05）;PI与孕周呈线性负相关（r=-0.170,P<0.05）;ET、RI与孕周无相关性（r=0.195、-0.197,P均>0.05）。 结论正常胎儿主肺动脉多普勒参数与孕周有一定的相关性,AT、AT/ET与胎儿孕周相关性最好。     

Sonographic estimation of fetal liver weight: an additional biometric parameter for assessment of fetal growth.

A single fetal ultrasonogram was obtained between the 20th and 40th weeks of gestation in 327 pregnancies. Fetal body weight was calculated with standard methods and fetuses were classified as appropriate for gestational age (303 fetuses), large for gestational age (four fetuses), or small for gestational age (20 fetuses). Fetal liver weight was estimated on the basis of longitudinal, anteroposterior, and cephalocaudal liver dimensions multiplied by a constant (k) of 0.42 determined experimentally in a previous study of adult livers. Estimated liver weights in appropriate for gestational age fetuses were not statistically different from published standards based on autopsy findings (P < 0.005). Similar findings were obtained in two other normal pregnancies examined serially until delivery. Estimation of fetal liver weight appears to be an accurate and reproducible method and may enhance sonographic assessment of fetal growth abnormalities and conditions with fetal liver involvement.     

Fractional spine length: a new parameter for assessing fetal growth

Sonographic measurement of a segment of the lower thoracic and lumbar fetal spine was performed on 218 normal fetuses of between 15 and 42 weeks' gestational age (GA) to establish a new parameter for assessing fetal growth. The increase of the fractional spine length (FSL) was represented by the equation: FSL = -37.62 + 4.36 (GA) - 0.04 (GA)2, with R2 = 0.92. The FSL also correlates strongly with fetal femur length (FL): FSL = 5.36 + 0.82 (FL), with R2 = 0.93. The ratio FSL/abdominal circumference (AC) X 100 was relatively constant at 20.4 +/- 3.1 (mean +/- 2 standard deviations) from 19 to 42 weeks in contrast to the ratio FL/AC X 100, which was constant at 22.3 +/- 2.4 (mean +/- 2 SD) only after 23 weeks. Nine of 10 small-for-gestational age fetuses examined during the study had a FSL within the normal range, as well as two fetuses who were thanatophoric dwarfs. The FSL provides a new ultrasonic longitudinal measurement of the fetus which may be used in addition to the femur length in fetal growth assessment.     

Prenatal detection of fetal aneuploidy by sonographic ear length.

OBJECTIVE: To determine the usefulness of a fetal ear length nomogram in the prenatal detection of fetal aneuploidy and to determine whether ear smallness in cases of aneuploidy is a primary or secondary event. METHODS: Ear lengths of 447 singleton fetuses (October 1996 to October 1997)were prospectively evaluated between 14 and 41 weeks to establish a nomogram created by modeling the mean and SD separately. Records of aneuploid fetuses were retrospectively reviewed, and their ear lengths were plotted against the nomogram to determine detection rates, with ear length in or below the 10th and 50th percentiles for a given gestational age and biparietal diameter used as abnormal cutoffs. RESULTS: The nomogram for fetal ear length measurements provided sufficient data to derive the 10th, 50th, and 90th percentiles on the basis of gestational age and biparietal diameter. The ear length of euploid fetuses was significantly correlated with gestational age (R2 = 0.96; P < .001) and biparietal diameter (R2 = 0.95; P < .001). From 96 aneuploid fetuses identified, 63 had ear lengths in or below the 10th percentile for gestational age (sensitivity, 66%). When using ear length against biparietal diameter, the sensitivities for all aneuploid fetuses for cutoffs at or below the 10th and 50th percentiles were 43% (40 of 93) and 83% (77 of 93), respectively. CONCLUSIONS: Most aneuploid fetuses have sonographically small ears (< or = 10th percentile for gestational age). This smallness is not entirely related to overall small fetal size, but in almost half the cases, the fetal ear length is disproportionately smaller than the biparietal diameter.     

Clavicular measurement: a new biometric parameter for fetal evaluation

Fetal clavicular length was measured sonographically in 85 fetuses with gestational ages ranging from 15 to 40 weeks. Biparietal diameter (BPD) and femur length (FL) were also measured. A linear correlation was found between clavicular length and gestational age (coefficient of correlation = 0.81). A simple relation was found: The gestational age in weeks is approximately equal to the length of the clavicle as expressed in millimeters. The measurement of clavicular length can be a useful parameter for the estimation of gestational age and in the detection of congenital anomalies that affect the clavicles. Clavicular measurements may also prove useful in the detection of macrosomic fetuses at high risk for obstructed labor or shoulder dystocia.     

Ear length in trisomy 21 fetuses at 11-14 weeks of gestation.

OBJECTIVE: To determine the value of measuring fetal ear length at 11-14 weeks of gestation in screening for chromosomal defects. METHODS: The fetal ear length was measured in 450 fetuses immediately before chorionic villus sampling for karyotyping at 11-14 weeks of gestation. RESULTS: The median gestational age was 12 (range, 11-14) weeks. The fetal ear was successfully examined in all cases. The fetal karyotype was normal in 409 cases and abnormal in 41, including 32 cases of trisomy 21. In the chromosomally normal group the fetal ear length increased significantly with crown-rump length from a mean of 3.7 mm at 45 mm to 6.9 mm at 84 mm. In the trisomy 21 fetuses the median ear length was significantly below the normal mean for crown-rump length by 0.45 mm (P = 0.013) but it was below the 5(th) centile of the normal range in only two (6.3%) of the cases. There was no significant association between the delta score of ear length and delta nuchal translucency in either the chromosomally normal (r = - 0.015, P = 0.753) or the trisomy 21 fetuses (r = - 0.014, P = 0.94). CONCLUSIONS: At 11-14 weeks of gestation the ear length in trisomy 21 fetuses is significantly reduced but the degree of deviation from normal is too small for this measurement to be useful in screening for trisomy 21.     

正常胎儿眼球横径、周长、截面积及眼距的超声研究与临床价值

【目的】探讨超声方法观察胎儿眼球横径、周长、截面积及眼距的生长规律及其与孕周的相关性。【方法】从接受胎儿超声系统筛查和常规产前超声检查的孕龄13～40周胎儿中选取符合条件的2988例进入样本库,在常规检查后对其胎儿眼球横径、周长、截面积及眼距进行测量,按孕龄分组,并进行相关统计学处理。【结果】胎儿眼球横径、周长、截面积及眼距在13～40周中随孕龄增加而增长,与孕周呈线性相关（r=0．87～0．92,均P〈0．01）;左、右眼球横径、周长及截面积在各孕周间无明显统计学差异（P〉0．05）。【结论】胎儿眼球横径、周长、截面积与孕龄呈正相关,超声检查为评价胎儿眼部发育情况提供了一种简便实用的方法。胎儿眼距正常参考值的确立,有助于检查出胎儿眼距过宽或过窄。     

First-trimester umbilical cord diameter: a novel marker of fetal aneuploidy.

OBJECTIVE: To compare the umbilical cord diameter at 10-14 weeks of gestation of chromosomally normal and abnormal fetuses. METHODS: In a consecutive series of women, who were undergoing routine sonographic evaluation at 10-14 weeks of gestation, umbilical cord diameter and nuchal translucency were measured. Reference ranges for umbilical cord diameter according to gestational age and crown-rump length were constructed. Fetal karyotype was obtained at chorionic villus sampling, amniocentesis or at delivery in newborns with features suspicious for chromosomal abnormalities. RESULTS: During the study period, 784 patients met the inclusion criteria. Of these, a fetal or placental chromosomal abnormality was present in 17 cases. The mean umbilical cord diameter increased with gestational age (r = 0.41, P < 0.001).The proportion of fetuses with an umbilical cord diameter above the 95th centile was higher in the presence of fetal or placental chromosomal abnormalities than in normal fetuses (5/17 vs. 39/767, P < 0.01). Among fetuses with an abnormal fetal or placental karyotype, nuchal translucency was above the 95th centile for gestational age in 10 cases.When only fetal chromosomal abnormalities were considered (n = 14), the combined detection rate was 85.7%(12/14). CONCLUSIONS: Sonographic assessment of the umbilical cord in early gestation appears to identify a subset of fetuses at increased risk of chromosomal abnormalities.     

定量组织速度成像评价正常胎儿房室环运动

目的 应用定量组织速度成像(QTVI)检测正常胎儿房室环运动速度并分析其与孕龄和心率的关系.方法 对受检正常胎儿187例,采用QTVI检测不同孕龄二尖瓣环、三尖瓣环及室间隔收缩期运动速度(Sm)、舒张早期运动速度(Em)、舒张晚期运动速度(Am)及心率,分别比较不同孕期房室环运动速度间差异,并观察其与孕龄和心率的关系.结果 (1)胎儿二尖瓣环、三尖瓣环及室间隔Sm、Em、Am均随孕龄增加而增加,与心率无线性相关;除二尖瓣环Em外,各取样部位运动速度的提高集中发生在33～36周;(2)各孕龄胎儿的Em均低于Am;(3)三尖瓣环Sm、Em、Am高于二尖瓣环及室间隔(P＜0.01),二尖瓣环与室间隔Sm、Em、Am间差异无统计学意义.结论 QTVI能够评估正常胎儿心脏功能,并观察其动态变化,揭示胎儿心脏功能的发育成熟过程.     

Fetal penile length.

OBJECTIVE: To construct a reference range for fetal penile length. METHODS: The length of the penis was measured during ultrasound assessment of 95 structurally normal male fetuses of gestational ages 16-38 weeks. Two fetuses with bladder outflow obstruction were also examined. RESULTS: Fetal penile length increases significantly with gestational age, from a mean value of 6.0 mm at 16 weeks to 26.4 mm at 38 weeks. One fetus with urethral agenesis had a penile length on the 0.3rd centile. CONCLUSIONS: Measurement of the fetal penis is easy and not time-consuming. In cases of bladder outflow obstruction, assessment of penile length assists in the differentiation between urethral agenesis and posterior urethral valves.     

Development of the human fetal corpus callosum: a high-resolution, cross-sectional sonographic study.

OBJECTIVE: To establish reference ranges during human pregnancy for normal fetal corpus callosum dimensions. DESIGN: In a prospective, cross-sectional study of 258 fetuses between 16 and 37 weeks of gestation, measurements of the length, width, and thickness at the level of the anterior mid-body of the corpus callosum were performed, using high-resolution, transvaginal and transabdominal transducers. RESULTS: The mean length of the corpus callosum was 27.2 (standard deviation, 1.2; 95% confidence interval, 26.02-28.37) mm. Width and thickness of the corpus callosum were 5.6 (standard deviation, 1.6; 95% confidence interval, 5.41-5.82) mm and 1.9 (standard deviation, 0.7; 95% confidence interval, 1.87-2.06) mm, respectively. The size of the corpus callosum as a function of gestational age was expressed by regression equations: length (mm) = -20.40 + 1.92 x gestational age; width (mm) = -0.052 + 0.225 x gestational age; thickness (mm) = -0.174 + 0.085 x gestational age. The dimension-gestational age correlation coefficients were: r = 0.779 for length, r = 0.676 for width and r = 0.494 for thickness; these were statistically significant (P < 0.01). The maximum increase in thickness and width of the corpus callosum occurred between 19 and 21 weeks' gestation, while its length followed a constant growth rate. The normal mean length, width and thickness of the corpus callosum per week, and the 95% confidence limits, were defined. CONCLUSIONS: The present study offers normative measurements of the fetal corpus callosum and may facilitate a more objective diagnosis of its congenital abnormalities.     

Fetal transverse cerebellar diameter measurements in normal and reduced fetal growth.

OBJECTIVES: To establish the increase in fetal transverse cerebellar diameter (TCD) relative to gestational age during normal and restricted fetal growth; to determine the significance of TCD and TCD/AC relationship in predicting fetal outcome as expressed by perinatal mortality. DESIGN: A retrospective cross-sectional study. SUBJECTS: Three hundred and sixty normally developing fetuses between 17 and 34 weeks of gestation and 73 growth-restricted fetuses between 24 and 34 weeks of gestation. METHODS: Ultrasonographic measurements included head circumference (mm), abdominal circumference (mm) and transverse cerebellar diameter (mm). A gestational age-related normal reference chart was produced for TCD. RESULTS: Statistically significant relationships between transverse cerebellar diameter and gestational age, abdominal circumference and head circumference were found. The normal fetal TCD exhibited a more than twofold increase in size during the second half of pregnancy. Twenty-six per cent of the small-for-gestational age (SGA) fetuses displayed a reduced TCD and 82% of the SGA fetuses demonstrated raised TCD/AC values. No statistically significant difference in perinatal mortality or birth weight was found between the subsets of growth-restricted fetuses with reduced or normal TCD; or between the subsets with normal or raised TCD/AC values. CONCLUSIONS: In the normally developing fetus the TCD increases with advancing gestational age. Increased TCD/AC values are suspicious of fetal growth restriction. The perinatal mortality in growth-restricted fetuses with a small cerebellum is increased twofold over that of other fetuses.     

Growth of the fetal gall bladder in normal pregnancies.

Our objective was to obtain dimensions of the fetal gall bladder as a basis, for further studies and to establish normative data to assess deviations in growth. The study group included 183 normal pregnant women from 13 to 40 weeks' gestation. Routine biometric measurements were obtained on all fetuses, including biparietal diameter, head and abdominal circumferences and measurements of the long bones and the two diameters of the fetal gull bladder. The gall bladder area and circumference were calculated for each gestational age.A linear growth function was observed across the gestational age and a first-degree correlation was found to exist between gestational age and both the longitudinal (r = 0.77067; p < 0.00001; y = -0.41060 + 0.0907 x gestational age) and transverse (r = 0.602; p < 0.00001; y = 0.58567 + 0.01925 x gestational age) diameters of the fetal gall bladder. A significant correlation was also found between gull bladder area and gestational age (r = 0.6878; p < 0.00001), biparietal diameter (r = 0.72768; p < 0.00001), abdominal circumference (r = 0.71363; p < 0.00001) and femoral length (r = 0.72190; p < 0.00001). In addition, a significant correlation was found between gall bladder circumference and gestational age (r = 0.76181; p < 0.00001), biparietal diameter (r = 0.80039; p < 0.00001), abdominal circumference (r = 0.78030; p < 0.00001) and femoral length (r = 0.79694; p < 0.00001).These results provide normative data of the fetal gall bladder in various dimensions and across gestational age. In addition, the data offer the potential for prenatal diagnosis of additional lesions in the extrahepatic biliary duct system.     

Nomograms of sonographic measurements throughout gestation of the fetal hard palate width, length and area.

OBJECTIVE: To assess the feasibility of sonographic depiction of the fetal hard palate and secondarily to create nomograms throughout gestation of its sonographic width, length and area. METHODS: This was a cross-sectional study of pregnant patients between 15 and 41 weeks' gestation. Inclusion criteria consisted of well-established dates (confirmed by early ultrasound), and singleton, non-anomalous fetuses. Sonographic measurements obtained included biparietal diameter, head circumference, abdominal circumference and femur length. Fetal hard palate measurements included maximum width, maximum length and the calculated area. Tables were prepared depicting the estimated mean +/- SD and 5(th), 50(th) and 95(th) centiles at each gestational week between 15 and 41 weeks. Pearson's correlation coefficient and associated P-values for the relationships between fetal hard palate measurements and other sonographic measurements and coefficients of variation for each of the fetal hard palate measurements were calculated. RESULTS: The study included 602 consecutive patients. The mean maternal age was 28.7 +/- 6.3 years, with median gravidity of 2 (range, 1-12) and parity 1 (range, 0-8). All attempts at obtaining fetal hard palate ultrasound measurements were successful. Mean fetal hard palate width (cm) = -0.73579345 + 0.11370432 x GA - 0.00083919 x GA(2) and SD = -0.017842055 + 0.005142475 x GA, where GA is gestational age in weeks. Mean fetal hard palate length (cm) = -0.82020463 + 0.11767777 x GA - 0.00092801 x GA(2) and SD = -0.043064317 + 0.006378869 x GA. Mean fetal hard palate area (cm(2)) = -2.40090641 + 0.17136556 x GA + 0.00097308 x GA(2) and SD = -0.603647741 + 0.040740282 x GA. Sonographic measurements of the fetal hard palate width, length and area correlated significantly and strongly with gestational age (all P < 0.001) and significantly but less strongly with femur length (P = 0.004). CONCLUSION: The fetal hard palate may be depicted sonographically with relative ease between 15 and 41 weeks' gestation and measurements of the fetal hard palate width, length and area correlate well with gestational age, biparietal diameter, abdominal circumference, sonographic estimated fetal weight, and femur length.     

Evaluation of Fetal Spine Biometry Between 11 and 14 Weeks of Gestation

This study was designed to establish a fetal spine nomogram for age 11 through 14 weeks of gestation and to document relations among fetal spine length, distance and angle. These parameters were prospectively measured during the first trimester of singleton pregnancies, along with nuchal translucency, over a 3-year period. A total of 430 fetuses were included in the study. The regression equations among fetal spine parameters and gestational age were as follows: Spine length (mm) = 1.116 × gestational age (days) − 59.169; spine distance (mm) = 1.079 × gestational age (days) − 59.038; head–spine angle = 0.740 × gestational age (days) + 4.735; spine length:spine distance ratio = −0.002 × gestational age (days) + 1.234. Prenatal age-specific reference intervals for fetal spine biometry between 11 and 14 weeks of gestation may assist in evaluation of fetuses investigated for genetic abnormalities that can be expressed by deviation in spine length, distance, or angle. (E-mail: pjcheng@cgmh.org.tw)     

Fetal trunk and head volume in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation.

OBJECTIVE: To examine the pattern of growth in chromosomally abnormal fetuses at 11+0 to 13+6 weeks of gestation and compare the trunk and head volume to crown-rump length (CRL) in defining the growth deficit in such fetuses. METHODS: The fetal trunk and head volume was measured using three-dimensional (3D) ultrasound in 140 chromosomally abnormal fetuses at 11+0 to 13+6 (median 12) weeks of gestation, and the values were compared to 500 chromosomally normal fetuses. In each chromosomally abnormal fetus, the observed fetal trunk and head volume was subtracted from the expected mean (delta value) of the chromosomally normal fetuses of the same gestational age, and this difference was expressed as a percentage of the appropriate normal mean. The Mann-Whitney U-test was used to determine the significance of differences between the chromosomally normal and abnormal groups. RESULTS: In trisomy 21 (n=72) and Turner syndrome (n=14) fetuses, compared to chromosomally normal fetuses, the CRL for gestation was similar (P=0.335 and P=0.317, respectively), but the fetal trunk and head volume was about 10-15% lower (P<0.001 and P=0.004, respectively). In trisomy 18 (n=29), trisomy 13 (n=14) and triploidy (n=11), the deficit in volume was about 45% (P<0.001), whereas the deficit in CRL was less than 15% (P<0.001). CONCLUSIONS: In the quantification of the degree of early growth impairment in chromosomally abnormal fetuses, measurement of the fetal trunk and head volume using 3D ultrasound may be better than measurement of CRL.     

超声测定正常胎儿心脏房室瓣环、腔室径及其与胎龄的相关性

目的建立不同孕周时超声测定胎儿心脏各腔室径的正常值,探讨心脏测值随孕周变化的规律。方法将胎龄为16～40周的552胎正常胎儿按照胎龄分为13组,应用高分辨二维超声心动图测量其房室瓣环径、二、三尖瓣距离(M-TD)及心脏各腔室径,计算正常均值,对各测定值与胎龄绘制散点图进行相关和回归分析,选择最优化方程。结果胎儿期心脏结构各测定值随胎龄增加而增大,与孕周呈显著正相关(P均<0.01);M-TD与胎龄呈线性相关,二、三尖瓣环径及其他心脏各腔室测值与胎龄之间呈非线性相关,曲线拟合显示二次多项式方程拟合度最优。结论正常胎儿心脏房室瓣环径、M-TD以及其他房室腔各测值随胎龄而增大,与孕周呈显著正相关。     

Assessment of fetal adrenal gland volume using three-dimensional ultrasound

To assess the normal fetal adrenal gland volume during normal gestation, we performed a prospective study on 119 normal fetuses with gestational age ranging from 21 to 40 weeks using a 3-D ultrasound (US) volume scanner with a pure cross-sectional design. Polynomial regression analysis was calculated to find the best-fit model between gestational age (GA) and adrenal gland volume. In addition, estimated fetal weight (EFW) was also measured to demonstrate the correlation between adrenal gland volume and fetal weight. Our results showed that fetal adrenal gland volume is highly correlated with GA. Furthermore, using GA as the independent variable and adrenal gland volume as the dependent variable, the best-fit regression equation was adrenal glands volume (mL) = -0.2683 x GA + 0.0082 x GA(2) + 3.1927 (r = 0.93, n = 119, p < 0.0001). For clinical use, a chart of normal growth centiles of fetal adrenal gland volume in utero was then calculated based on this equation. In addition, fetal adrenal gland volume during normal gestation is also highly correlated with EFW (p < 0.0001). In conclusion, our data of fetal adrenal gland volume assessed by 3-D US can serve as a useful reference in evaluating fetal growth status during gestation.