Ultrasonographic measurements of the fetal neck correlated with gestational age

Ultrasonographic examinations were performed on 121 normal fetuses between 15 to 40 weeks of gestation to measure the fetal neck. The area (FN-A), circumference (FN-C), anteroposterior diameter (FN-APD) and transverse diameter (FN-TD) of the fetal neck correlated well with the gestational age, respectively. Ultrasonographic measurements of the fetal neck in utero are thus new parameters to evaluate the fetal growth and identify the abnormality of the fetal neck in utero.     

Non protein bound iron concentrations in amniotic fluid

OBJECTIVES: To investigate whether amniotic fluid concentrations of non protein bound iron (NPBI) vary with growth in healthy fetuses and also offer a reference curve in the second trimester of pregnancy. DESIGN AND METHODS: Amniotic fluid concentrations of NPBI were measured by HPLC in 118 women with physiological singleton pregnancies, who underwent amniocentesis for fetal karyotype between weeks 15 and 18 of gestation. RESULTS: NPBI increased progressively from weeks 14--15 to weeks 15--16, peaking at 17--18 weeks of gestation. NPBI values regressed positively with gestational age (GA). Multiple linear regression analysis between NPBI, as dependent variable, and various fetal parameters, as independent variables, showed a statistically significant regression coefficient with GA, bi-parietal diameter and transverse cerebellar diameter. CONCLUSIONS: The present data constitutes the first quantification of NPBI concentrations in amniotic fluid under physiological conditions. Correlations with GA and ultrasound fetal biometry suggest that NPBI may play a role in fetal growth.     

超声检测孕11～13+6周胎儿颅内透明层的研究

目的探讨超声在妊娠早期测量胎儿颅内透明层(IT)内径即第四脑室前后径作为筛查开放性脊柱裂观察指标的价值,建立孕11～13+6周胎儿颅内透明层正常参考值范围。方法采用经腹超声,选取孕11～13+6周头臀径(CRL)测值在45～84mm范围内的胎儿369例,在胎儿面部正中矢状面上,测量脑干和脉络丛之间颅内透明层厚度,并与头臀径测值进行比较。结果 369例胎儿中367例显示颅内透明层并测量,2例不能显示颅内透明层,超声诊断为开放性脊柱裂并经终止妊娠后确诊。367例胎儿头臀径平均测值为(60.038±9.569)mm,中位数为59mm;颅内透明层平均厚度为(1.562±0.243)mm,中位数为1.50;颅内透明层测值随孕周增加而增加,其数值从头臀径45mm时颅内透明层为1.3mm增加到头臀径84mm时颅内透明层为2.0mm(P<0.01)。结论在孕11～13+6周正常胎儿中,颅内透明层清晰显示,随孕周增长而呈线性增加。在早孕期颅内透明层的变小或消失是开放性脊柱裂有价值的观察指标。     

产前超声对于胎儿子宫的评估

目的利用超声测量不同孕周胎儿子宫的前后径及横径,建立胎儿期子宫前后径及横径与孕周的关系。方法收集285例19~37孕周的女性胎儿,横切面超声扫查,于胎儿低位盆腔内、膀胱与直肠之间测量其子宫前后径及横径,三次测量取平均值,利用SPSS 22.0软件进行统计分析。结果胎儿子宫前后径及横径均随孕周增加而增长,呈线性相关(R^2=0.919,P<0.001;R^2=0.920,P<0.001),经线性回归分析建立胎儿子宫前后径及横径与孕周的线性回归方程:子宫前后径(mm)=0.45×孕周-4.9,子宫横径(mm)=0.51×孕周-3.8;同时提供了各孕周胎儿子宫前后径及横径的均数、标准差及95%可信区间。结论女性胎儿子宫在孕19周后产前超声扫查可显示,其前后径及横径与孕周呈线性正相关。     

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.     

A prospective evaluation of fetal femur length as a predictor of gestational age.

Variability (+/- 2 SD) in prediction of fetal gestational age from ultrasonographic measurements of fetal femur length was evaluated prospectively in 287 fetuses between 18 and 42 weeks' gestation. Variability increased throughout pregnancy, ranging from +/- 11.6 days between 18 and 24 weeks to +/- 22.7 days in the last six weeks of pregnancy. These findings are comparable with variability in prediction of gestational age from biparietal diameter measurement between 18 and 42 weeks, which indicates that the femur length may serve as an adequate alternative for prediction of gestational age in cases in which the biparietal diameter cannot, for technical reasons, be obtained.     

二维斑点追踪成像技术对超重及肥胖女性孕中晚期胎儿心室构型变化的评估

目的应用二维斑点追踪成像（2D-STI）评价孕前超重及肥胖女性孕中晚期胎儿心室构型变化。 方法回顾性选取2019年6月至2020年3月于空军军医大学唐都医院进行胎儿超声心动图检查的孕妇80例,根据孕前体质量指数（BMI）将其分为正常对照组30例、超重组27例和肥胖组23例。应用胎儿超声心动图获得常规胎儿心脏形态学指标,采用2D-STI技术并利用Fetal HQ软件获得孕24周及孕32周胎儿双侧心室24节段舒张末期横径及球形指数（SI）,3组间进行单因素方差分析,并采用LSD-t检验进一步行组间两两比较。 结果常规方法测量肥胖组、超重组与正常对照组孕妇胎儿的左、右心室舒张末期横径,左、右心室舒张末期长径,心胸面积比及左心室每搏输出量,3组间差异均无统计学意义（P均＞0.05）。孕中期（孕24周）肥胖组室间隔厚度较正常对照组增厚［（2.10±0.41）mm vs（1.85±0.33）mm］,孕晚期（孕32周）肥胖组室间隔厚度较正常对照组及超重组均增厚［（3.10±0.65）mm vs（2.46±0.52）mm、（2.55±0.53）mm］,差异均有统计学意义（P均＜0.05）。2D-STI测得肥胖组左心室横径孕24周第6~12节段及孕32周第7~12节段分别较同孕龄正常对照组明显增宽,肥胖组左心室SI孕32周第4~12节段较正常对照组明显降低（P均＜0.05）。2D-STI测得肥胖组右心室横径孕24周第3~10节段及孕32周第1~8节段分别较同孕龄正常对照组明显增宽,肥胖组右心室SI孕32周第1~9节段较正常对照组明显降低（P均＜0.05）。 结论孕前肥胖的孕妇胎儿左心室中间段、右心室基底段节段性横径增宽,与正常对照者相比更接近球形,提示测量左心室中间段及右心室基底段横径可更敏感地反映孕前肥胖孕妇胎儿心室形态的改变。     

Fetal gastric size in normal and abnormal pregnancies.

OBJECTIVE: The aim of this observational study was to construct an ultrasound index of fetal gastric size for the prenatal detection of congenital digestive tract obstruction. SUBJECTS: A total of 386 fetal measurements were performed in routine ultrasonographic examinations of women with normal singleton pregnancies between 18 and 39 weeks of gestation. Gastric measurements were also performed in 13 fetuses with digestive tract obstruction. METHODS: The ultrasound plane which included the pylorus and which provided the largest stomach area was used for definition and measurement of gastric area and maximal longitudinal dimension. The transverse section at the center of the gastric corpus was used for transverse and anteroposterior dimensions. Gastric volumes were calculated as a prolate ellipsoid. The gastric area ratio was defined as the gastric area divided by the transverse abdominal area. Biparietal diameter (BPD) and abdominal transverse area were also measured. RESULTS: The fetal gastric area was significantly correlated with fetal gastric volume (r = 0.91) and gestational age (r = 0.74). However, the correlation coefficient for gastric area with gestational age was smaller than those of the BPD (r = 0.97) with gestational age and abdominal transverse area with gestational age (r = 0.97). Gastric area ratio decreased slightly towards term. The gastric area ratio was below the 95% confidence intervals for the predicted values in all five fetuses with esophageal atresia, and exceeded the 95% confidence intervals in seven of the eight fetuses with duodenal atresia or intestinal tract obstruction. CONCLUSION: Fetal gastric area correlates with ultrasound-determined gastric volume measurements and appears to be useful in the assessment of digestive tract anomalies.     

Application of 3‐Dimensional Ultrasonography to Imaging the Fetal Anal Canal

Objective. Ultrasonography has been applied previously to the assessment of the fetal anal canal. We aimed to examine the potential of 3‐dimensional ultrasonography (3DUS) in the evaluation of the fetal anal canal and to obtain normal fetal anal canal measurements. Methods. Patients were recruited from an unselected population of gravidas with known gestational age (by dates or first‐trimester ultrasonography) and without known fetal anomalies presenting for fetal evaluation in the ultrasound units of 2 tertiary care centers between 16 and 39 gestational weeks. In addition to the ordered scan, 3DUS imaging of the fetal anal canal was performed. Transverse and sagittal views and volumes were obtained. Measurements of the fetal anal canal anteroposterior diameter, lateral diameter, and length were performed in transverse and sagittal planes, respectively, and scatterplots of these dimensions were created. Measurements were performed and repeated on raw data sets by 2 independent observers, and the results were analyzed to estimate interobserver and intraobserver reliability. Results. A total of 186 patients were examined for this study at 16 to 39 weeks' gestation (mean, 27.4 weeks). The anteroposterior diameter of the fetal anal canal in this study group ranged from 4 to 21 mm (mean, 11.2 mm; SD, ±3.5 mm), whereas the lateral diameter ranged from 7 to 18 mm (mean, 9.1 mm; SD, ±3.0 mm). The length of the fetal anal canal in this study group ranged from 3 to 24 mm (mean, 14.3 mm; SD, ±3.8 mm). Conclusions. Ultrasonographic assessment of the fetal anal canal with 3DUS is feasible. Scatterplots were created for internal anal sphincter width and length measurements from 16 to 39 weeks' gestation. Larger studies are necessary to establish nomograms of these measurements and their application to the evaluation of pathologic cases. We speculate that 3DUS assessment of the fetal anal canal may improve detection rates of disorders involving this system.     

Ultrasonographic nomograms of the fetal fourth ventricle: additional tool for detecting abnormalities of the posterior fossa.

OBJECTIVE: To characterize normal growth of the fetal fourth ventricle on ultrasonography throughout pregnancy. METHODS: Consecutive biometric measurements and fetal organ scans were obtained from 299 patients undergoing fetal anatomic surveys between 13 and 40 weeks' gestation. Using 7- and 3.5-MHz transducers for early (13- to 17-week) and late (>17-week) examinations, respectively, we scanned the fetal head in the axial plane with special focus on the posterior fossa of the brain. The fourth ventricle was identified, and its anteroposterior diameter and width were measured. A "triangle" formula was used for calculating its circumference and area. RESULTS: The fourth ventricle was shown as a hypoechoic triangle below the level of the cerebellum. A linear regression line of the fourth ventricle was observed across gestational age, and a first-degree correlation was found between gestational age and anteroposterior diameter of the fourth ventricle (r = 0.894; P < .0001; y = -0.84 + 0.23 x gestational age), its width (r = 0.657; P < .0001; y = 3.82 + 0.14 x gestational age), its circumference (r = 0.843; P < .0001; y = 5.11 + 0.58 x gestational age), and its area (r = 0.844; P < .0001; y = -10.11 + 1.17 x gestational age). Twelve enlarged fourth ventricles were found between 14 and 16 weeks, but results of follow-up scans at 20 weeks were normal. CONCLUSIONS: An isolated enlarged fourth ventricle in the early second trimester might represent a normal variant; it should be followed, but decisions about the fate of the pregnancy should not be based solely on this finding.     

Relative growth of the higher fetal brain structures

In a retrospective review of 90 normal obstetric ultrasonographic examinations obtained between 15 and 35 menstrual weeks, measurements were made of the transverse dimensions of the thalamus, basal ganglia/insula, atrium of the lateral ventricle, and temporal operculum in the standard biparietal diameter plane. At 15 menstrual weeks the echogenic choroid plexus, filling the lateral ventricle, dominates the appearance of the cranium. During later gestation, the cerebral hemispheres and basal ganglia (telencephalic structures) show marked growth, while the diencephalon and lateral ventricles increase much less rapidly in size. This observation is made using a method of measurement that least favors the demonstration of cerebral cortical growth. Of note is that the width of the lateral ventricle remains relatively stable throughout the second and third trimesters.     

Fetal transabdominal biometry at 11-14 weeks of gestation.

OBJECTIVE: To establish comprehensive transabdominal ultrasonographic reference ranges for viable normal singleton human fetuses at 11-14 weeks' gestation. METHODS: Single transabdominal ultrasound measurements were taken once per pregnancy at a gestational age of between 11+0 and 14+0 weeks (crown-rump length, 45-84 mm), in viable singleton fetuses with nuchal translucency < or = 3 mm and without detectable structural anomalies, using four standard planes: (i) biparietal diameter (BPD) and fronto-occipital diameter (FOD) resulting in head circumference (HC), anterior horn (Va), posterior horn (Vp), and hemisphere (HEM); (ii) transcerebellar diameter (TCD) and cisterna magna (CM); (iii) abdominal anteroposterior (AAP) and abdominal transverse diameter (ATD) resulting in abdominal circumference (AC); and (iv) femur length (FL). The respective ratios Va/HEM, Vp/HEM, HC/AC, BPD/FL, BPD/FOD, FL/CRL, FL/BPD and FL/AC and the estimated weight were derived. Reference ranges were constructed and the mean and 5th and 95th centiles were plotted against gestation. RESULTS: There was a general increase in biometric parameters with gestation. The ratios for the ventricles vs. hemisphere and BPD/FL ratio decreased while the BPD/FOD and HC/AC ratios remained constant. Analysis of the reference range for BPD/FL was performed in both 167 and 664 fetuses and the results showed almost the identical type of equation, indicating a high degree of accuracy for the growth charts. CONCLUSIONS: We have established comprehensive reference ranges for first-trimester fetal biometry by transabdominal sonography. These charts may have a role in the diagnosis of early onset symmetrical or asymmetrical growth restriction and in the interpretation of measurements in chromosomally abnormal fetuses, and they may help in the detection of skeletal dysplasias or acrania/anencephaly.     

Nomogram of the fetal alveolar ridge: a possible screening tool for the detection of primary cleft palate.

OBJECTIVE: The objective of this study was to obtain a nomogram of the fetal alveolar ridge development, as a basis for the diagnosis of primary cleft palate. DESIGN: A cross-sectional study of 323 normal pregnant women of 14-32 weeks' gestation. Several biometric measurements were obtained throughout pregnancy, including the width of the fetal alveolar ridge. RESULTS: A nomogram of the width of the fetal alveolar ridge during 14-32 weeks' gestation is presented. A linear growth function was observed between alveolar ridge width and gestational age, biparietal diameter, head circumference, femoral length and humeral length. The alveolar ridge width in all eight cases of cleft palate was above two standard deviations and the 90th centile of our nomogram. CONCLUSION: We provide a nomogram of the growth of the fetal alveolar ridge between 14 and 32 weeks' gestation. This will aid the detection of primary cleft palate during routine prenatal sonography.     

Diameter of the normal fetal thymus on ultrasound.

OBJECTIVE: To present the normative data of the transverse diameter of the developing fetal thymus. METHODS: In this prospective study, the maximum transverse diameter of the thymus was measured by one sonologist in 376 normal fetuses between 19 and 38 weeks of gestation. We assessed the relationship of the transverse thymic diameter with gestational age (GA), biparietal diameter, femur length and abdominal circumference using general linear regression modeling. The predicted mean and 95% reference range of thymic diameter at each GA were calculated from the regression equation. RESULTS: Measurements of the transverse diameter were possible in 352 of the 376 (94%) fetuses. The transverse diameter of the fetal thymus increased with increasing GA and fetal size parameters in a linear manner. The regression equation for transverse diameter of the thymus as a function of GA was: thymic diameter (cm) = 0.15 x GA (weeks) - 1.59 (r(2) = 0.86, P < 0.001). CONCLUSION: The transverse diameter of the fetal thymus is easy to measure; this study presents normative data.     

In-utero development of the fetal colon and rectum: sonographic evaluation.

OBJECTIVE: To construct a normal range for the internal diameter of the fetal descending colon and rectum during gestation. SUBJECTS AND METHODS: This was a prospective, cross-sectional study including 379 healthy pregnant women with normal singleton pregnancies at 19-40 weeks of gestation. Measurements of the fetal descending colon (maximum internal diameter) and the fetal rectum (at the level of the bladder, measuring the anteroposterior diameter), were performed by high-resolution transabdominal sonography. RESULTS: Adequate bowel measurements were obtained in all 379 fetuses. The diameter of the descending colon and rectum plotted as a function of gestational age had a sigmoid curve; the curve estimation was expressed by a cubic regression equation with R(2) of 0.848 and 0.831, respectively (P < 0.0001). The normal mean and the 95% prediction limits were defined. CONCLUSION: The present data provide a normal range of fetal bowel (descending colon and rectum) diameters from the early second trimester of pregnancy onwards. They may allow intrauterine assessment of the development of the fetal colon and may serve as reference values in the detection of anomalies of the fetal bowel.     

Comparison of biparietal diameter and femur length in the third trimester: effects of gestational age and variation in fetal growth

A multiple regression-based statistical model capable of quantitatively comparing two or more sonographic parameters for the effects of gestational age, variation in fetal growth and error in sonographic measurement is presented and then used to compare the biparietal diameter and femur length as estimators of gestational age in late pregnancy. A total of 311 patients were studied between 24 and 42 weeks' gestation. Variation in fetal growth was expressed as the birth weight percentile for gestational age. Biparietal diameter and femur length correlated equally well with gestational age. However, the biparietal diameter was more than twice as sensitive as the femur length to variation in fetal growth. Femur length had a larger error associated with its measurement. These results suggest that the biparietal diameter and femur length in late pregnancy are equal estimators of gestational age; that the femur length is a more stable estimator of gestational age when fetal growth deviates from normal; and that the femur length is technically more difficult to obtain.     

Growth of the fetal forehead and normative dimensions developed by three-dimensional ultrasonographic technology.

Sonographic imaging of the fetal face is important since a number of chromosomal aberrations are associated with facial malformations. In the past, imaging of the fetal forehead and diagnosis of frontal bossing had been based on subjective evaluation using two-dimensional ultrasonography. The purpose of this study was to evaluate quantitatively the fetal forehead using three-dimensional technology to generate normative data throughout gestation. This should allow the objective diagnosis of abnormal growth of the fetal forehead, such as frontal bossing. We also report a case of a fetus with frontal bossing in whom the generated nomogram was applied. A cross-sectional study was performed in 130 normal healthy singleton pregnancies between 16 and 38 weeks' gestation. Using three-dimensional ultrasonography, a line connecting the apex of the philtrum and the nasion was drawn across the anterior forehead, which delineated the area of the forehead for analysis. The forehead length, forehead height, and forehead area under the curve were measured and the forehead index was calculated. A second order polynomial growth function was noted throughout gestation for the forehead length (r = 0.93), forehead height (r = 0.97), and forehead area (r = 0.97). The fetal forehead index remained relatively constant throughout gestation. The results of this study provide normative data of fetal forehead length, width, and area using three-dimensional ultrasonographic technology. Normative dimensions of the fetal forehead developed and presented herein are expected to serve as a basis for the objective assessment of presumed fetal facial abnormalities and may facilitate the detection of the associated syndromes. This is demonstrated in our case report of an achondroplastic fetus in whom all forehead dimensions were above the 95th percentile.     

胎儿超声心动图检查定量11~17周正常胎儿主动脉和肺动脉内径Z-评分的初步研究

目的探讨早孕期（11^＋0周~13^＋6周）和中孕早期（14^＋0周~17^＋6周）胎儿主动脉内径（AO）与肺动脉内径（PA）与胎儿生物学生长参数的相关性,初步建立早孕期和中孕早期胎儿AO与PA的正常参考值范围及Z-评分方程,并评价方程的有效性。 方法随机选取孕周（GA）为（11^＋0周~17^＋6周）正常单胎胎儿270例,将成功显示左、右心室流出道切面的245例胎儿纳入研究,获得胎儿顶臀径（CRL）、双顶径（BPD）、股骨长径（FL）、孕周（GA）等生物学生长参数。在胎儿左、右心室流出道切面测量收缩末期AO及PA,以GA、BPD和FL作为独立自变量,AO及PA作为因变量,建立AO、PA的正常参考值范围,并对每个参数的绝对残差（SD）进行加权回归,建立Z-评分方程。 结果采用简单的线性回归模型,可以很好地描述AO和PA与非心脏生物特征参数（BPD、FL、GA）的关系。AO、PA与GA、BPD、FL均呈显著线性相关（GA与AO：r=0.9276,GA与PA：r=0.9271,BPD与AO：r=0.9551,BPD与PA：r=0.9558,FL与AO：r=0.9462,FL与PA：r=0.9483,均<0.001）,其中与BPD的相关性最强。 结论正常早孕期及中孕早期胎儿的AO、PA随着孕周的增加而增长,本研究初步建立了正常胎儿早孕期及中孕早期AO、PA的参考范围及其Z-评分方程。为早孕期及中孕早期评估胎儿大血管生长提供精确的参考标准,在早期筛查或诊断胎儿先天性心脏畸形方面具有潜在的应用价值。     

A prospective longitudinal study of growth in twin gestations compared with growth in singleton pregnancies. II. The fetal limbs

The assessment of fetal growth is crucial in twin gestations, since the information gained often has an impact on pregnancy management. The measurement of the fetal anatomy by ultrasound enables us to follow the growth and development of the fetus. However, the pattern of fetal growth in twin gestations has not yet been precisely characterized in prospective studies. In this light, we initiated a prospective longitudinal study and sonographically examined 35 patients with twin gestations every 3 weeks from the 15th week until delivery. Multiple biometric parameters were measured, including the femur length, humerus length, ulna length, and tibia length. The results of our study showed that growth of these long bones was not significantly different between twins A and B throughout gestation and that the growth velocity between twins and singletons was not significantly different. The incremental growth, although significantly less in twins than in singletons, was so small that it was judged not to be of clinical importance to warrant the generation of separate nomograms for the evaluation of growth in twin gestations.     

Nomograms of fetal thyroid measurements estimated by 2-dimensional sonography

PURPOSE: To build nomograms of fetal thyroid circumference (FTC), fetal thyroid area (FTA), and fetal thyroid transverse diameter (FTTD) throughout gestational age (GA). METHOD: Between January 2006 and July 2006, FTC, FTA, and FTTD were measured once in 196 normal fetuses examined at a GA of 22-35 weeks. Inclusion criteria were a healthy mother with normal maternal thyrotropin level during pregnancy, a singleton pregnancy with normal fetal morphology on sonography, and GA confirmed via first-trimester sonographic examination. RESULTS: Mean FTC, FTA, and FTTD ranged from 3.21 cm, 0.58 cm(2), and 1.19 cm at 22 weeks to 5.11 cm, 1.69 cm(2), and 1.89 cm at 35 weeks, respectively. Linear regression analysis yielded the following formulas for FTC, FTA, and FTTD according to GA: FTC (cm) = 0.146 x GA (weeks); FTA (cm(2)) = -1.289 + 0.085 x GA (weeks); FTTD (cm) = 0.054 x GA (weeks). The following logarithmic formulas were obtained for the expected fetal thyroid measurements according to estimated fetal weight (FW): FTC (cm) = -4.791 + 1.265 x logN FW; FTA (cm(2)) = -1.676 + 0.455 x logN FW; and FTTD (cm) = 0.399 + 0.001 x logN FW. CONCLUSION: We describe new nomograms of fetal thyroid measurements throughout gestation that may be useful in case of thyroid dysfunction.