Growth of the fetal stomach in normal pregnancies

Fetal stomach dimensions were measured sonographically in 152 fetuses with gestational ages ranging from nine to 40 weeks. Nomograms of the mean +/- 2 standard deviations (SD) for the longitudinal, anteroposterior, and transverse diameters of the fetal stomach were generated throughout pregnancy. A linear growth function was observed across gestational age, and a high degree of correlation existed between gestational age and the transverse (r = 0.809, P less than .0001), anteroposterior (r = 0.798, P less than .0001), and longitudinal (r = 0.749, P less than .0001) diameters. These data provide a method by which variations from the norm can be assessed, and offer potential prenatal diagnosis of a variety of gastrointestinal lesions.     

Cerebellar measurements with ultrasonography in the evaluation of fetal growth and development

A prospective study of ultrasonography was conducted in 371 normal pregnant women, with gestational ages ranging from 13 weeks to 40 weeks. Several biometric measurements were obtained including the transverse cerebellar diameter, the biparietal diameter, the occipitofrontal diameter, and the calculated head circumference. Curvilinear relationships were found between the transverse diameter of the cerebellum (measured in millimeters), and the gestational age (R2 = 0.948; P = 0.001), the biparietal diameter (R2 = 0.956; P = 0.0001), and the head circumference (R2 = 0.969; P = 0.0001). A nomogram of cerebellar measurements estimating gestational age and predicting the biparietal diameter and head circumference was generated. Throughout pregnancy the establishment of normative cerebellar measurements allows for the estimation of gestational age that is independent of the shape of the fetal head and offers potential for evaluation of abnormal fetal growth and anomalous development of the central nervous system.     

Ultrasound evaluation of fetal spine length between 14 and 24 weeks of gestation.

The objective of our study was to establish a nomogram of fetal spine length in the second trimester of pregnancy by using two and three-dimensional ultrasound. Fetal spine length was measured prospectively by means of transabdominal ultrasonography in 114 normal singleton pregnancies between 14 and 24 weeks of gestation. Regression analyses were performed on spine length, gestational age, biparietal diameter and femur length. Supplementary three-dimensional ultrasound to assess fetal spine length was performed in 75 cases. Fetal spine length, as a function of gestational age, was expressed by the following regression equation: spine length (mm) = -47.2 + 7.16 x gestational age (weeks), with a Pearson correlation coefficient of R(2)=0.956. The results of the measurements revealed no difference between two and three-dimensional ultrasound. Our study defines the normal limits of fetal spinal length in the second trimester of pregnancy and demonstrates a high correlation between spinal length, gestational age, biparietal diameter and femur length. However, there are still too few prenatal research data to say whether and to what extent an assessment of fetal spine length at this stage of pregnancy can be used for prenatal diagnosis of congenital syndromes, which, among other manifestations, are marked by fetal spine lengthening or shortening.     

Measuring the rate of fetal urine production using three-dimensional ultrasound during normal pregnancy and pregnancy-associated diabetes

Abstract

Objective: To establish a nomogram of fetal urine production according to gestational age as a predictor for fetal well-being in normal and diabetic women.

Study design: Prospective observational study included 180 pregnant women classified into two groups: Group I (120 women) without any medical complications and Group II (60 women) with gestational diabetes mellitus (GDM). The fetal bladder is measured by the virtual organ computer-aided analysis VOCAL 3D ultrasound scanner.

Results: There was a significant positive correlation between gestational age and fetal urine production rate (UPR) (the mean UPR rate in normal pregnancy at 25, 30, 35, 40 weeks were 12.3, 14.38, 56.13 and 90.73?ml/h, respectively). There was no significant difference regarding UPR ml/h between women with normal pregnancy and those with controlled GDM (p?=?0.9). There was a statistically significant difference regarding UPR ml/h between women with normal pregnancy and those with uncontrolled GDM (p?=?0.012) and a statistically significant difference between women with controlled GDM and those with uncontrolled GDM (p?=?0.03).

Conclusion: Fetal UPR is considered to be more reliable as an assessment method for fetal well-being and shows significant increase in patients with uncontrolled gestational DM.     

Thyroid-stimulating hormone in singleton and twin pregnancy: importance of gestational age-specific reference ranges

OBJECTIVE: To estimate a normal reference range for thyroid-stimulating hormone (TSH) at each point in gestation in singleton and twin pregnancies. METHODS: All women enrolling for prenatal care from December 2000 through November 2001 underwent prospective TSH screening at their first visit. Separate nomograms were constructed for singleton and twin pregnancies using regression analysis. Values were converted to multiples of the median (MoM) for singleton pregnancies at each week of gestation. RESULTS: Thyroid-stimulating hormone was evaluated in 13,599 singleton and 132 twin pregnancies. Thyroid-stimulating hormone decreased significantly during the first trimester, and the decrease was greater in twins (both P < .001). Had a nonpregnant reference (0.4-4.0 mU/L) been used rather than our nomogram, 28% of 342 singletons with TSH greater than 2 standard deviations above the mean would not have been identified. For singleton first-trimester pregnancies, the approximate upper limit of normal TSH was 4.0 MoM, and for twins, 3.5 MoM. Thereafter, the approximate upper limit was 2.5 MoM for singleton and twin pregnancies. CONCLUSION: If thyroid testing is performed during pregnancy, nomograms that adjust for fetal number and gestational age may greatly improve disease detection. Values expressed as multiples of the median may facilitate comparisons across different laboratories and populations.     

Fetal transverse cerebellar diameter in different ethnic groups

AIMS: Transverse cerebellar diameter has been described as a tool to check for gestational age, but there are no available studies that attempt to determine differences in transverse cerebellar diameter between groups of different ethnic origin. The present study was undertaken to check for differences in ultrasound-measured transverse cerebellar diameter between pregnant women of autochthonous Belgian origin and migrant women from Morocco and Turkey. METHODS: A prospective cross-sectional study was performed. Patients were pregnant women presenting between 17 and 40 weeks of gestational age. Only uncomplicated singleton pregnancies with a known date of the last menstrual period confirmed by first trimester ultrasound were included. The father of the child had to be of the same ethnic origin as the mother. Polynomial regression was fitted for the three different ethnic groups. RESULTS: The transverse cerebellar diameter was obtained in 471 singleton fetuses, including 333 Belgian, 69 Moroccan and 69 Turkish. F-tests on the residual sums of squares of different fits demonstrated significant effects of ethnicity on the regression of the measurement versus gestational age (P < 0.00005). In a third order polynomial regression model the second order coefficient was significantly higher and the third order coefficient was significantly lower for the Moroccan group. CONCLUSION: The transverse cerebellar diameter is not independent of the ethnic origin of the patient. When using the transverse cerebellar diameter for the evaluation of fetal growth or for dating a pregnancy, care should be taken to rely on charts appropriate for the ethnic group, as demonstrated here for Moroccan fetuses.     

Ultrasonographic ear length measurement in normal second- and third-trimester fetuses

OBJECTIVE: We sought to develop a nomogram for fetal ear length measurements from a large population of healthy second- and third-trimester fetuses and to investigate the correlation of fetal ear length with other standard fetal biometry measurements, as follows: biparietal diameter, head circumference, abdominal circumference, femur length, and humerus length. STUDY DESIGN: Ear length measurement was obtained prospectively in 4240 singleton fetuses between 15 and 40 weeks' gestational age. Either complete data for normal karyotype on amniocentesis or normal infant examination at birth or both were available in 2583 cases. These constituted the final study population. RESULTS: A nomogram was developed by linearly regressing ear length on gestational age (Ear length [in millimeters] = 1.076 x Gestational age [in weeks] - 7. 308). There was a high correlation between ear length and gestational age (r = 0.96; P =.0001). CONCLUSION: The results of this study provide normative data on growth of fetal ear length from 15 to 40 weeks' gestation. Good correlation was also observed between ear length and other fetal biometric measurements (biparietal diameter, head circumference, abdominal circumference, femur length, and humerus length).     

The three-vessel and tracheal view of the fetal heart: an in utero sonographic evaluation

OBJECTIVES: To establish a nomogram for fetal cardiac three-vessel view diameter changes during gestation. METHODS: The study is a prospective cross-sectional evaluation of 338 male and female fetuses between 14 and 38 weeks of normal singleton pregnancies. Measurements of fetal pulmonary artery, aorta and superior vena cava diameters, performed on a transverse view of the upper mediastinum were conducted using transvaginal ultrasonography between 14 to 18 weeks and transabdominal after 19 weeks' gestation. RESULTS: Adequate measurements of the three cardiac vessels were obtained in 338 fetuses. The regression equations for vessel diameters modeled as function of gestational age were pulmonary artery diameter (mm) = -2.275 + 0.273 x gestational age (week), aorta diameter (mm) = -1.77 + 0.227 x gestational age (week), and SVC diameter (mm) = -0.98 + 0.142 x gestational age (week). The correlation coefficients between gestational age and the diameter of the vessels were, r = 0.93, r = 0.93 and r = 0.86 for pulmonary artery, aorta and SVC respectively (all found to be highly statistically significant, p < 0.0001). The normal mean and 90% prediction limits were defined. CONCLUSION: Our data present the normal range of fetal heart three-vessel diameters during gestation. They may allow intrauterine assessment of their development and an adjunct in the detection and evaluation of great vessel pathology.     

Estimated fetal weight in the evaluation of growth in twin gestations: a prospective longitudinal study

A prospective longitudinal study was conducted in order to determine by sonographically estimated fetal weight the patterns of fetal growth in twins. Thirty-five healthy women with normal twin pregnancies were examined every three weeks from the 15th week of gestation to delivery. Among the measurements obtained were the biparietal diameter (BPD), the abdominal circumference, and the calculated fetal weight. From 15-28 weeks, the growth velocity of the BPD and abdominal circumference remained fairly constant, with a steady increase in incremental growth. Beyond this age, we observed a slowing in growth of the BPD, while the abdominal circumference continued at a constant rate. The growth velocity of the weight steadily increased throughout pregnancy. Although greater biologic variability in weight between twin A and B was observed as gestational age progressed, the overall mean weights of twin A and B were not statistically different. We have generated a nomogram of fetal weight gain throughout pregnancy.     

Sonographic Measurement of Umbilical Vein and Umbilical Cord Diameters in Normal and Diabetic Pregnancies

Sonographic visualization of umbilical cord components is becoming increasingly important in evaluating fetal well-being. Standard graphs of umbilical vein and cord measurements during the last two trimesters of 219 normal singleton pregnancies showed a linear increase in transverse dimensions with advancing gestational age. Preliminary data on 38 pregnancies complicated by maternal diabetes mellitus, showed significant deviations from normal umbilical measurements.     

Embryonic trunk circumference: a new biometric parameter for estimation of gestational age

One hundred thirty-one uncomplicated, singleton pregnancies between 7 and 12 weeks of gestation were ultrasonically examined. Evaluation included confirmation of cardiac activity and measurements of fetal crown-rump length and trunk circumference. Both crown-rump length and trunk circumference were curvilinearly correlated with gestational age. A second- and third-degree polynomial equation best described this curvilinear relationship between trunk circumference and gestational age and between crown-rump length and gestational age. The crown-rump length and trunk circumference were similar in their prediction of gestational age, but the combination of the two parameters did not improve the prediction of gestational age. A nomogram of gestational age as predicted by trunk circumference was generated. These data provide an additional measurement for the estimation of gestational age in the first trimester of pregnancy.     

Prenatal measurement of the fetal cerebellum and cisterna cerebellomedullaris by ultrasound

The fetal cerebellum can be visualized with ultrasound throughout the second trimester. We describe a technique for measuring the transverse and anteroposterior cerebellar diameters and the measurement of the cisterna magna in the same plane between 14 and 32 weeks gestation. Nomograms for these measurements against gestational age showed good correlation, and narrow confidence limits for the transverse cerebellar diameter. The transverse cerebellar diameter was also measured directly in 79 fetuses after midtrimester abortion and the measurements obtained were compared with the ultrasound TCD nomogram. Good correlation, was obtained between the post mortem measurements and the ultrasound TCD nomogram. Routine use of these measurements and nomograms should prove valuable in the diagnosis of congenital abnormality of the posterior fossa and may also be of use in assessing the effect of severe intrauterine growth retardation and other insults on cerebellar growth and development. The narrow confidence limits obtained with the TCD nomogram should enable it to be used with confidence in clinical practice.     

The fetal mandible: an in utero sonographic evaluation between 11 and 31 weeks' gestation

OBJECTIVE: To construct a growth chart of the mandible throughout gestation. METHODS: A prospective cross-sectional study of normal singleton pregnancies was conducted. Measurements of the fetal mandibular transverse and antero-posterior diameters were performed with high-resolution transvaginal and transabdominal ultrasonography in 490 pregnant women with singleton low-risk pregnancies between 11 and 31 weeks' gestation. RESULTS: The mandibular transverse and antero-posterior diameters were recorded by week of gestation and the ratio was calculated: mandibular ratio (MR) = 1.7759 - 0.01047 x gestational week. There was a negative linear correlation (-1.047%) for each incoming week of gestation. Normal values (+/-1SD and 2SD) were established. CONCLUSION: The present data provides a normal range of fetal mandibular diameters during normal pregnancies and introduces a new parameter, the mandibular ratio, for the intrauterine assessment of the fetal mandibular development.     

Impact of maternal fasting during Ramadan on fetal Doppler parameters,maternal lipid levels and neonatal outcomes

Objective: The aim of the present study was to evaluate whether fasting may cause changes in maternal lipid profile, glucose level and ketonuria, and whether it has any adverse effects on fetal Doppler, birthweight, preterm delivery or cesarean section rate.

Methods: Fifty-six consecutive, healthy women with singleton uncomplicated pregnancies of ≥28 week gestation who had fasted for at least 10 consecutive days during the study period were defined as the study group. Fifty-four healthy non-fasted women matched for age, parity, and gestational age were defined as the control group. Groups were compared according to fetal middle cerebral artery and umbilical artery systolic/diastolic ratio, maternal serum lipid levels and neonatal outcomes (gestational age at delivery, birthweight, delivery type and neonatal intensive care admission).

Results: No statistical difference was found between the groups according to fetal Doppler parameters, amniotic fluid index, gestational age at delivery, cesarean section rate, birthweight or NICU admission. However, lower levels of VLDL, triglyceride and higher incidence of ketonuria were detected in the fasting group (p?<?0.05).

Conclusion: Fasting of healthy women during pregnancy seems to have no adverse effects on amniotic fluid index, fetal Doppler and delivery parameters.     

Fetal transcerebellar diameter measurement with particular emphasis in the third trimester: a reliable predictor of gestational age

OBJECTIVE: The purpose of this study was to validate prospectively a previous retrospectively established nomogram for the prediction of gestational age using transcerebellar diameter, especially in the third trimester. STUDY DESIGN: In a previous study, we retrospectively constructed a cross-sectional nomogram using transcerebellar diameter measurements in 24,026 well-dated singleton fetuses. In the present study, this nomogram was validated prospectively on the basis of patients who were seen between August 2002 and May 2003 and who were carrying non-anomalous and non-malformed singleton gestations between 14 and 42 weeks (n = 2597 gestations). The actual gestational age was then subtracted from the predicted gestational age, and the concordance between actual and predicted gestational ages was assessed based on the Pearson correlation (r). RESULTS: Concordance between the actual and predicted gestational age was high (r = 0.92; P < .0001). This agreement was superior in the second trimester (r = 0.93; P < .0001) than in the third trimester (r = 0.81; P < .001). Between 17 and 21 weeks, and between 22 and 28 weeks of gestation, the predicted gestational age ranged between 0 and 4 days, and between 0 and 2 days, respectively, of actual gestational age. Between 29 and 36 weeks of gestation, predicted gestational age was within 5 days of actual gestational age; at 37 weeks of gestation, the predicted gestational age was discrepant by 9 days. CONCLUSION: This prospective study demonstrates that transcerebellar diameter measurement is an accurate predictor of gestational age, even in the third trimester of pregnancy.     

A novel reference chart and growth standard of fetal biometry in the Taiwanese population

ObjectiveThe purpose of this study was to establish a new reference chart and growth standards for fetal biometry in Taiwan.Materials and methods2047 singleton pregnancies were enrolled in this study with 15,813 fetal scans between 18 and 40 gestational weeks. A reference chart and normal range for fetal biparietal diameter (BPD), abdominal circumference (AC) and femur length (FL) was established by longitudinal quantile regression model. 330 women with comorbidities including gestational hypertension, preeclampsia and gestational diabetes were excluded and 1717 pregnant women were enrolled for the growth standard.ResultsThe new reference values were significantly larger across all gestational ages compared with the prior National Taiwan University reference chart in 1983. Compared with Intergrowth-21st, the BPD was larger at 18–23 weeks, the AC was larger at 18–24 weeks and the FL was larger at 18–36 weeks whereas they were all smaller at 29–40 weeks for the BPD, at 32–40 weeks for the AC and at 38–40 weeks for the FL. A quantile regression equation of biometry was established. BPD, AC, and FL had weekly growth of 2.5, 9.87 and 2.15 mm. Prepregnancy body weight, height, age, and gestational diabetes increased fetal size. Both gestational and chronic hypertension decreased fetal size.ConclusionTo promote maternal-fetal safety, a new reference chart and growth standard for fetal biometry is necessary to measure fetal growth.     

The FL/AC ratio for prediction of shoulder dystocia in women with gestational diabetes

Purpose: To determine if sonographic variables, including fetal femur length to abdominal circumference (FL/AC) ratio, are associated with shoulder dystocia in women with gestational diabetes.

Methods: This was a retrospective cohort study of women with gestational diabetes who delivered singleton infants at Parkland Hospital from 1997 to 2015. Diagnosis and treatment of gestational diabetes were uniform including sonography at 32–36 weeks. Biometric calculations were evaluated for correlation with shoulder dystocia.

Results: During the study period, 6952 women with gestational diabetes underwent a sonogram at a mean gestation of 34.8?±?1.8 weeks. Of 4183 vaginal deliveries, 66 experienced shoulder dystocia (16/1000). The FL/AC was associated with shoulder dystocia (p?p?=?0.54) whereas age-adjusted AC and HC/AC were not (p?Conclusions: The FL/AC is associated with shoulder dystocia in women with gestational diabetes. Additionally, it is a simple ratio that is independent of the reference used and remains stable, unlike age-adjusted AC and HC/AC ratio.     

The umbilical cord thickness measured at 18-23 weeks of gestational age.

OBJECTIVE: To establish an umbilical cord thickness nomogram from anatomy ultrasound scans performed between 18 and 23 weeks of gestational age in singleton pregnancies, and compare it to two previously published nomograms. MATERIAL AND METHODS: In this retrospective cohort study of 1107 patients, a total of 650 singleton pregnancies were included. The umbilical cord diameter measurements were performed at the level of fetal abdominal wall insertion, and were correlated with gestational age (GA) and estimated fetal weight (EFW). Statistical analysis with non-parametric polynomial least squares regression analysis was performed. RESULTS: A statistically significant correlation between umbilical cord diameter and GA (P<0001, r=0.399, 95% CI 0.331 to 0.464), and EFW (P<0001, r=0.420, 95% CI 0.353-0.483) was observed. A nomogram of umbilical cord thickness according to GA (y), and EFW (y'), was generated from the following equations:y=-51.30+5.367*x-0.1165*x(2) and y'=6.917+0.007233*x, respectively. CONCLUSION: Our nomogram is in agreement with one of the previously published nomograms that also measured umbilical cord diameter at the level of the fetal abdominal umbilical cord insertion. Therefore, we recommend umbilical cord thickness to be measured in close proximity to the fetal abdominal wall, but no further than 0.5 cm away from the wall insertion.     

Gender- and parity-specific reference charts for fetal size in low risk singleton pregnancies at the onset of the third trimester

OBJECTIVES: To determine fetal growth in low risk pregnancies at the beginning of the third trimester and to assess the relative importance of fetal gender and maternal parity. SETTING: Dutch primary care midwifery practice. STUDY DESIGN: Retrospective cohort study on 3641 singleton pregnancies seen at a primary care midwifery center in the Netherlands. Parameters used for analysis were fetal abdominal circumference (AC), fetal head circumference (HC), gestational age, fetal gender and maternal parity. Regression analysis was applied to describe variation in AC and HC with gestational age. Means and standard deviations in the present population were compared with commonly used reference charts. Multiple regression analysis was applied to examine whether gender and parity should be taken into account. RESULTS: The fetal AC and HC increased significantly between the 27th and the 33rd week of pregnancy (AC r2=0.3652, P<0.0001; HC r2=0.3301, P<0.0001). Compared to some curves, our means and standard deviations were significantly smaller (at 30+0 weeks AC mean=258+/-13 mm; HC mean=281+/-14 mm), but corresponded well with other curves. Fetal gender was a significant determinant for both AC (P<0.0001) and HC (P<0.0001). Parity contributed significantly to AC only but the difference was small (beta=0.00464). CONCLUSION: At the beginning of the third trimester, fetal size is associated with fetal gender and, to a lesser extent, with parity. Some fetal growth charts (e.g., Chitty et al.) are more suitable for the low-risk population in the Netherlands than others.