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PubMedDate not supplied

Volumetric flow in the umbilical artery: normative data.

OBJECTIVE: Provide normative data for the volumetric blood flow (cc/min and cc/min/kg) in the umbilical artery. METHODS: Flow was determined from an umbilical artery in 252 normal obstetrical patients from 18-40 weeks' gestation utilizing pulsed Doppler and color flow Doppler with an angle of insonation of 30-60 degrees. Simultaneous velocimetry studies (S/D ratio, resistance and pulsatility indices), fetal biometry, and an anatomic survey were obtained to further define the normal population. RESULTS: There was a steady increase in the flow (cc/min) in the umbilical artery as pregnancy progressed. Flow/kg showed a steady decline as fetal weight increased. Umbilical artery diameter increased until reaching a plateau at 32-34 weeks. Velocimetric results were consistent with known data. CONCLUSIONS: Volumetric blood flow in the umbilical artery can be determined with relative ease and normative data from 18-40 weeks is presented for the first time.

Adult↗

PubMedDate not supplied

Placental vessel morphometry in growth retardation and increased resistance of the umbilical artery Doppler flow.

OBJECTIVES: To study the tertiary-stem villi vessel lumen and wall thickness of placenta in pregnancy complicated with placental insufficiency and intrauterine growth retardation (IUGR), its correlation with the umbilical artery Doppler flow study, and compare with normal and non-IUGR pregnancies. METHODS: Placentas from 45 deliveries (between 28 and 38 weeks) were collected for morphometric study of the tertiary-stem villi vessels. Each pregnancy had clinical suspicion of IUGR and was confirmed by serial ultrasound biometry, HC/AC ratio, and had abnormal umbilical artery Doppler velocimetry (RI). Each placenta was weighed after trimming of the membrane and the cord. Sections of the placenta (4 micron) were stained with hematoxylin and eosin and periodic acid-Schiff reagents. Tertiary-stem villi vessels were identified under a microscope (x40) and morphometric study was performed. Inner and outer circumferences (2.pi.r) were measured, radii (r) were calculated, and vessel wall thickness was determined (outer r - inner r). These findings were compared with the findings from 78 placentas from normal pregnancies (between 28-40 weeks) and 27 placentas from pregnancies with medical complications without IUGR (non-IUGR) and with normal Doppler velocimetry (between 33 and 38 weeks). RESULTS: Weight of placentas were significantly (P < 0.005) lower in IUGR than the normal and non-IUGR groups. The vessel wall thickness was significantly (P < 0.0001) increased in IUGR group (mean 21.17 +/- 3.16 micron [SD]) compared to normal and non-IUGR groups (mean 13.19 +/- 1.66 micron). With advancing gestational age, the thicknesses of vessel walls in all groups were significantly (P < 0.001) decreased. There was significant (P < 0.001) decrease in lumen circumference in the IUGR group (mean 173 +/- 31 micron) compared to normal and non-IUGR groups (mean 69 +/- 23 micron). Significant (P < 0.001) correlation was observed between the thickness of a vessel wall and the increase in Doppler RI. CONCLUSIONS: Pregnancies with growth retardation are associated with smaller placentas, increase in the thickness of tertiary-stem villi vessel wall, and decrease in lumen circumference. These changes are associated with an increase in the resistance index of the umbilical artery Doppler flow velocimetry.

Adult↗

PubMed1988

Ultrasonographic prenatal diagnosis and fetal pathology of Langer mesomelic dwarfism.

In a family at risk for Langer mesomelic dwarfism, we document the onset of disproportionate growth in the second trimester by sonographic biometry. Midtrimester pathologic correlation of this condition demonstrates primary changes in the growthplate in the regions of proliferating cartilage and hypertrophic and degenerative chondrocytes.

Adult↗

PubMed1991

Biomechanical changes in the rabbit masticatory system during postnatal development.

Using dissection, biometry, and two three-dimensional mechanical models, the postnatal changes of the rabbit masticatory muscles were studied by analyzing their three-dimensional orientation, their strength and fiber lengths, and certain functional consequences of these changes. The first mechanical model uses length-tension relationships of the muscles and predicts the maximum bite force as a function of mandibular position. It shows that young rabbits are able to generate large bite forces at a wider gape than adult animals and that the forces are directed more vertically. In spite of the postnatal changes the mechanical advantage of the system remains about equal. However, the muscles are reoriented so that they exert a larger degree of parallel action, suggesting a larger bite force magnitude but a smaller range of bite force directions. The second model-predicts this range. It shows that during postnatal development a relative gain occurs in the possibilities for the system to exert forces directed rostrodorsally. In all other directions the capability to exert force decreases. The results suggest that during development the possibility of the system to generate large bite forces is increased at the cost of a restriction in the range of jaw excursion and that a restriction takes place in the range of possible force directions that can be exerted at the molars.

Animals↗

PubMed1991

Quantification of training in obstetrical ultrasound: a study of family practice residents.

This study was done to determine how rapidly physicians in training could become competent in performing obstetrical ultrasound for the purposes of routine evaluations (i.e., the standard examination as defined by AIUM). The scan measurements and results of organ surveys of 12 family medicine residents were compared with the results obtained by faculty members experienced in obstetrical ultrasound. Residents rapidly became proficient in biometry. The mean menstrual age calculated from BPD, AC, HC, and FL differed from faculty values by 0.381 weeks after residents had performed 40 supervised scans. Organ survey success rates demonstrated similar high concordance between resident and faculty scans.

Faculty, Medical↗

PubMed2005

Prenatal sonographic diagnosis of truncus arteriosus associated with holoprosencephaly.

We present the case of a truncus arteriosus associated with holoprosencephaly detected in a fetus in the first trimester and the sonographic findings that established this diagnosis. A physical exam was performed on a 35-year-old pregnant woman, gravida 2, para 1. At 20 weeks, sonography showed large-for-date uterine size. Fetal biometry was consistent with menstrual age. Amniotic fluid volume was elevated to 25 AFI cm. Fetal echocardiography revealed a single common artery arising from the heart, a ventricular septal defect, and other cardiac defects. Abnormalities of the fetal brain and face were also shown via sonography, including the presence of a common lateral ventricle without falx cerebri. Alobar holoprosencephaly, the most severe form of holoprosencephaly, was diagnosed. Prenatal chromosomal analysis was offered and the patient elected to have cordocentesis. The chromosome study was normal. Success in surgical repair of truncus arteriosus is established, but alobar holoprosencephaly is associated with neonatal death. Continuation of the pregnancy carried risks for the mother. After proper counseling, the parents of this fetus were offered and accepted termination of pregnancy. A male abortus weighing 320 grams was delivered. Postnatal findings and autopsy confirmed the diagnosis.

Adult↗

PubMed2007

Gestational diabetes mellitus: fetal liver length measurements between 21and 24 weeks' gestation.

PURPOSE: To evaluate sonographic measurements of the fetal liver, fetal abdominal fat layer, interventricular septum, and Wharton's jelly area between 21 and 24 weeks' gestation in women with gestational diabetes mellitus (GDM). METHODS: A total of 123 consecutive healthy pregnant women underwent sonographic examination at 21-24 weeks' gestational age. The measurements included fetal biometry, detailed anomaly scan, and fetal body composition measurements (subcutaneous fat, liver size, cardiac muscle thickness, and Wharton's jelly area). GDM was confirmed by way of a 75-g oral glucose tolerance test using World Health Organization criteria within 1 week of the examination. RESULTS: Nineteen (15.4%) women were diagnosed with GDM, while 104 (84.6%) women were without GDM. The mean fetal liver length was 36 mm (95% CI 32-37) in women with GDM and 31 mm (95% CI 30-33) in women without GDM (p < 0.01). Liver enlargement was related to maternal fasting glucose levels and not 2-hour postprandial levels. There was no significant difference in the fetal biometric and other fetal body measurements between the 2 groups. CONCLUSIONS: The findings of this study suggest that midtrimester fetal liver length appears to be longer in GDM than in normal pregnancies. However, the fetal abdominal fat layer, interventricular septum, and Wharton's jelly were not affected. Nevertheless, further, larger randomized studies are required to confirm these findings.

Adipose Tissue↗

PubMed2006

Early condition, song learning, and the volume of song brain nuclei in the zebra finch (Taeniopygia guttata).

Songbirds are an important model system for the study of the neurological bases of song learning, but variation in song learning accuracy and adult song complexity remains poorly understood. Current models of sexual selection predict that signals such as song must be costly to develop or maintain to constitute honest indicators of male quality. It has been proposed that reductions of nestling condition during song development might limit the expression of song learning. Adult song could thus act as an indicator of early stress as only males that enjoy good condition during development could learn accurately and sing long songs or large repertoires. We tested this hypothesis in the zebra finch by modifying early condition through cross-fostering chicks to small, medium, and large broods. Song learning was very accurate and was found to reflect very closely tutor song characteristics and to depend on the number of males in the tutoring group. Although the brood size manipulation strongly affected several measures of nestling condition and adult biometry, we found no relationship between early condition and song learning scores or song characteristics. Similarly, brain mass and high vocal center (HVC), robust nucleus of the arcopallium (RA), and lateral magnocellular nucleus of the anterior nidopallium (LMAN) volumes did not covary with nestling condition and growth measurements. We found no significant relationship between song repertoire size and HVC and RA volumes, although there was a nonsignificant trend for HVC to increase with increasing proportion of learnt elements in a song. In conclusion, the results provide no evidence for song learning to be limited by nestling condition during the period of nutritional dependence from the parents in this species.

Analysis of Variance↗

PubMed2005

Progressive neuronal degeneration of childhood: prenatal diagnosis by MRI.

We report two cases in the same family of progressive neuronal degeneration of childhood--Alpers syndrome--with prenatal MRI findings in one case. The first infant presented at birth with severe microcephaly, then rapidly evolved to progressive encephalopathy with refractory epilepsy, leading to death at 10 months. Biochemical investigations including liver function tests were normal. CT and MRI showed severe diffuse brain atrophy. The diagnosis of progressive neuronal degeneration of childhood was made on the clinical and imaging data. The second pregnancy was marked by gradual decrease of fetal cerebral biometry and a prenatal MRI performed at 32 weeks showed diffuse cortical atrophy, as observed in the sibling. The infant died at 5 months. Neuropathological findings were consistent with Alpers syndrome.

Abnormalities, Multiple↗

PubMed2005

Discordant growth in twins.

Discordant growth in twins contributes significantly to rates of perinatal morbidity and mortality. These rates vary according to chorionicity, timing of onset and severity. We have reviewed English language literature in Medline since 1980. It is clear that diagnosis of discordant growth has improved due to the use of serial ultrasound examination. Following the detection of differences in fetal size, diagnosis is facilitated by umbilical artery and fetal Doppler studies. Management options vary according to chorionicity, timing of onset and umbilical-fetal Doppler studies. The mode of delivery in discordant twins remains controversial. We conclude that ultrasound surveillance of twin gestations, combining serial biometry and selective Doppler studies, is effective in the recognition of significant intrauterine growth restriction in co-twins. Differences in etiology and management underscore the importance of establishing chorionicity routinely as soon as twin gestation is diagnosed.

Chorion↗

PubMed1994

Humerus and femur length in fetuses with Down syndrome.

The aim of the study was to assess the value of sonographic measurement of fetal humerus and femur lengths in the second trimester as a screening tool for Down syndrome (DS). We reviewed retrospectively fetal sonographic biometry made at the time of amniocentesis between 15 and 19 weeks. The study group consisted of 27 DS fetuses. The control group comprised 500 normal fetuses chosen randomly. The expected humeral and femoral lengths for a given biparietal diameter were estimated by linear regression equations from the 500 normal fetuses. Receiver operating characteristic curve analysis was performed to evaluate both the detection rate and the false-positive rate of different cut-off values of measured to expected lengths ratios. The median femur and humeral lengths in DS fetuses were 0.91 times the expected values. No significant differences in the detection rate and false-positive rate were found between the humerus and femur lengths. When the humeral and femoral lengths were combined, we observed a remarkable reduction in the false-positive rate. A measured to expected length ratio of 0.91 detected 44.4 per cent of DS fetuses with 7.6 per cent false positives. These results suggest that the combination of femoral and humeral lengths may permit a more efficient use of ultrasound in screening for Down syndrome than the use of either alone.

Down Syndrome↗

PubMed1995

Normal fetal growth in women with antiphospholipid syndrome treated with high-dose intravenous immunoglobulin (IVIG).

Antiphospholipid antibodies are associated with fetal distress and fetal death. Although different therapeutic regimens have been used, the incidence of fetal growth retardation varies between 30 and 60 per cent of reported cases. We report the evolution of fetal growth in patients with antiphospholipid antibody syndrome treated with high-dose intravenous immunoglobulins (IVIG). Fourteen patients with a history of recurrent spontaneous abortion and immunological diagnosis of antiphospholipid syndrome were followed longitudinally. Intravenous immunoglobulin at a dose of 0.5 g/kg body weight for two consecutive days was started from the fifth week of pregnancy and repeated every 4 weeks until the 33rd week of gestation. Fetal biometry was evaluated longitudinally from the appearance of the gestational sac at 4 weekly intervals. In the period between 26 and 34 weeks, the frequency of evaluation was increased to every 14 days. Data obtained were compared with a control group of 70 fetuses with uneventful pregnancies matched for gestational age. Neonatal weight is shown in relation to the centiles for the normal population. One patient out of 14 (7.1 per cent) developed gestational hypertension and abruptio placentae. No other pregnancy complications were seen. No proteinuria was found. The mean maternal age was 31.2 +/- 3.8 years. Median birth weight was 3433 g +/- 287. The median centile of the birth weight was 65.3 +/- 18.6. Mean gestational age at delivery was 1.3 weeks. No fetal or neonatal growth retardation was seen.(ABSTRACT TRUNCATED AT 250 WORDS)

Abortion, Habitual↗

PubMed2002

Compromise ultrasound dating policy in maternal serum screening for Down syndrome.

Routine ultrasound biometry is the method of choice for gestational dating when screening for Down syndrome. However, it is costly and an alternative policy is to restrict ultrasound to women most likely to have menstrual dating errors. This was evaluated by statistical modelling with parameters from 14,274 women screened between January 1997 and July 2001 using free beta-human chorionic gonadotrophin (free beta-hCG), alpha-fetoprotein (AFP) and unconjugated estriol (uE(3)). A total of 12,711 (89%) women had both ultrasound and menstrual gestations, but in 4101 (29%) women either the last menstrual period (LMP) was uncertain or a pill-withdrawal period, or there were irregular or abnormal length cycles. The LMP was not entered in the test request form for a further 1404 (9.8%) women. Routine ultrasound dating yielded a predicted detection rate higher than for menstrual dating by 3.9-7.1%, depending on the marker combination and cut-off. The false-positive rate was reduced by 0.2-1.1%. Selectively scanning the 39% with unreliable dates increased detection by 2.6-4.6%, and reduced the false-positive rate by 0.04-0.6%. Some centres only use the ultrasound estimate of gestation when it differs from the menstrual estimate by more than 7 days. Such a rule reduces the gain in detection rate to 2.5-4.6% for routine ultrasound and 1.7-3.1% with the compromise policy; the false-positive rate reductions are 0.06-0.6% and 0.0-0.3%, respectively. We conclude that if routine ultrasound is not financially and practically feasible, the compromise policy yields a clinically important improvement in screening performance compared to menstrual dating.

Adult↗

PubMed2002

Nuchal index: a gestational age independent ultrasound marker for the detection of Down syndrome.

OBJECTIVES: To determine if the ultrasound marker Nuchal Index (NIx) is gestational age independent, and to determine its specificity and sensitivity for Down syndrome (DS) identification. METHODS: Prospective cohort. A prospective database of fetal biometry and soft markers of aneuploidy was searched for fetuses with the following criteria: confirmed gestational age, at least two measurements of nuchal thickness and biparietal diameter, no major detectable fetal anomalies, and either normal karyotype or normal postnatal exam. Nuchal Index (NIx) was defined as 100x (mean nuchal thickness [mm])/(mean Biparietal Diameter [mm]). This cohort was divided into two groups according to the last digit of their hospital unit number. Initial analysis was carried out in the first group (analysis group), with the second group (normal) used to test the results. A prospective cohort of pre- and postnatally diagnosed DS fetuses with at least two measurements of nuchal thickness and biparietal diameter constituted the abnormal study group (abnormal) and was used to determine the sensitivity of the index. P value <0.05 was considered significant. RESULTS: Eight hundred and seventy-five fetuses constituted the control group with 455 in the analysis group and 420 in the normal group. In the analysis group, Pearson coefficient and ANOVA confirm that NIx was independent of gestational age between 14 + 0 and 22 + 6 weeks of gestation. For the analysis group, mean NIx was 7.72, (SD = 2.05) and a threshold value of 11.0 yielded a specificity of 94%. Fifty-two DS fetuses made up the abnormal group. Mean NIx in this group was 17.9 (SD = 13.9), which was highly significant (P < 0.00001) compared to the analysis group. Using an NIx threshold of 11.0, sensitivity for any DS was 61.5% (32/52) and specificity (normal group) was 96% (402/420) (False positive rate = 4%). If DS fetuses with effusions, hydrops, cystic hygromas or central nervous system (CNS) defects are excluded, the sensitivity for an NIx of 11.0 was 50.0% (20/40). CONCLUSIONS: Nuchal Index (NIx) can be assumed to be constant between 14 + 0 and 22 + 6. Using a threshold of 11.0, the sensitivity for any Down syndrome (DS) fetus was 62% (32/52) with a specificity of 96% (False positive rate = 4%). Even when obvious fetal conditions that can cause an increase in NIx are excluded, the sensitivity remains acceptable at 50%. NIx appears to be a useful, gestational age independent ultrasound marker for Down syndrome.

Biomarkers↗

PubMed2004

Individualized growth assessment of fetal soft tissue using fractional thigh volume.

OBJECTIVES: The main goals of this study were to introduce fractional thigh volume (TVol) as a new soft tissue parameter for fetal growth evaluation, define its relationship to menstrual age, and develop individualized fetal growth standards based on Rossavik growth models. METHODS: A prospective, longitudinal study of 22 fetuses was conducted with conventional biometry and TVol measurements by three-dimensional ultrasonography. Infant growth outcomes were determined from modified neonatal growth assessment scores. Rossavik functions (P = c(t)k+s(t)) were used to fit complete datasets to examine relationships between TVol and model coefficients. Second-trimester models were subsequently specified from the linear slopes of growth curves before 28.0 menstrual weeks with each fetus acting as its own control. Third-trimester trajectories and birth measurements were predicted for standard growth parameters and TVol. Observed and predicted measurements were compared using percent deviations and growth potential realization index values. Four additional infants, with serial prenatal scans and postnatal evidence of intrauterine growth restriction (IUGR), were also evaluated. RESULTS: All 22 fetuses had no evidence of growth abnormalities after delivery. Accelerated soft tissue deposition occurred in the fetal thigh by 28 menstrual weeks. A mean TVol start point of 9.0 +/- 1.4 menstrual weeks was consistent with embryological studies of thigh development. Rossavik functions fitted all TVol trajectories well (mean R2 = 0.998 +/- 0.002). By fixing the coefficient k at its mean value (2.976), the fit did not change and the variabilities of coefficients c and s were reduced. The mean percent deviation between observed and predicted third-trimester TVol measurements was -0.048 +/- 7.5%. Relatively early pathological deviations were observed for TVol in all four fetuses with IUGR; in these cases the abdominal circumference was abnormal in only one fetus and thigh circumference in none. CONCLUSIONS: Individualized growth assessment can be used to accurately predict TVol during the third trimester of pregnancy and at birth. Expected growth trajectories, from second-trimester data, do not rely on population-based standards because each fetus serves as its own control. This new parameter may allow earlier detection and improved monitoring of fetal soft tissue abnormalities such as IUGR.

Female↗

PubMed2005

Ultrasound diagnosis of fetal macrosomia: a comparison of weight prediction models using computer simulation.

OBJECTIVE: To assess the frequency of the diagnosis of macrosomia in relation to differing weight estimation formulae in unselected pregnancies. METHODS: Computer modeling techniques were employed. Computer modeling software generated correlated fetal biometry measurements according to published British standards, from 37 to 41 weeks' gestation. For each set of measurements, estimated fetal weights were obtained by a panel of 18 ultrasound weight formulae. The diagnosis of macrosomia was made if the fetal weight estimate was greater than 4500 g. Cohorts of 5000 pregnancies for each week of gestation were studied. RESULTS: The frequency of diagnosis of macrosomia increased progressively with advancing gestational age, with large increases between 40 and 41 weeks. The type of weight estimation formula had a profound influence on the frequency of diagnosis of macrosomia. Five of the formulae tested almost never returned a weight estimate greater than 4500 g. Three formulae yielded false positive rates in excess of 15%. The Hadlock group of formulae yielded frequencies of 0.3% to 14.6%. CONCLUSIONS: Most formulae tend to over-diagnose macrosomia at term. Intervention rates for suspected fetal macrosomia may be influenced by gestational age at the time of scan and the type of fetal weight estimation formula in use.

Birth Weight↗

PubMed2006

Comparison between color Doppler cineloop- and conventional spectral Doppler-derived maximum velocity and flow in the umbilical vein.

OBJECTIVE: To compare the umbilical venous flow velocity derived from color Doppler cineloop recordings with that derived from conventional spectral Doppler in normal pregnancies. METHOD: In 18 uncomplicated pregnancies between 19 and 39 weeks' gestation, color Doppler was used to find the maximum velocity in the cross-sectional vessel area of a free-floating loop of the umbilical vein. The maximum velocity was determined using the software tool HDI_Lab (Philips Medical Systems) after tracing the vessel area of interest. Conventional spectral Doppler was then used to determine the maximum velocity with the High-Q machine option. The cross-sectional area of the umbilical vein was determined using B-mode imaging and was subsequently used to determine the umbilical volume flow from both Doppler methods. Assuming a parabolic flow profile in the umbilical vein, the mean velocity is equal to half the maximum velocity. The fetal weight was estimated from fetal biometry using the four-parameter Hadlock formula. RESULTS: Maximum velocity was significantly (P = 0.003) higher with color Doppler cineloop (14.3 +/- 2.5 cm/s) compared with spectral Doppler (12.7 +/- 3.2 cm/s). Therefore, using the same cross-sectional area for both methods, the umbilical blood flow was significantly higher (P = 0.001) with color Doppler cineloop (127.9 +/- 59.0 mL/min) than it was with spectral Doppler (112.8 +/- 54.1 mL/min). The umbilical blood flow expressed as volume flow per kg fetal weight was significantly (P = 0.01) higher with color Doppler cineloop (126.0 +/- 57.0 mL/min/kg) than it was with spectral Doppler (115.0 +/- 53.0 mL/min/kg). CONCLUSIONS: Umbilical venous flow velocity derived from color Doppler cineloops is approximately 10% higher than that derived from spectral Doppler-derived velocity. The reduced angle dependence of the color Doppler cineloop technique and the large sampling area of the cross-sectional vessel should allow better determination of the correct maximum velocity in the umbilical vein.

Blood Flow Velocity↗

PubMed2006

Three-dimensional ultrasound in the prenatal diagnosis of cleidocranial dysplasia associated with B-cell immunodeficiency.

A patient with a singleton pregnancy was referred for three-dimensional ultrasonography (3DUS) at 18 + 3 weeks for suspected hypomineralization of the skull bones and absence of the nasal bones. Three-dimensional rendered images of the fetal skull revealed widening of the coronal sutures, absence of the squamous portion of the temporal bone, and absence of the occipital bone, except for two areas of ossification. In addition, a fractured right clavicle was identified. The remainder of the fetal anatomy was normal and biometry was appropriate for gestational age. Genetic amniocentesis revealed a 46,XX fetal karyotype. Family history was positive for a 5-year-old sibling with an open anterior fontanelle. Cleidocranial dysplasia was suspected. A female neonate was delivered by elective repeat Cesarean section at 40 + 3 weeks of gestation without complications and discharged home 3 days after delivery. Prenatal diagnosis was confirmed by physical and radiological evaluation. The infant died at 8 weeks of age due to respiratory syncytial virus pneumonia secondary to B-cell deficiency. RUNX2 mutations were not detected by molecular analysis. There are three relevant aspects to this case: (1) clear visualization of the widened fontanelles and hypomineralized occipital bones was possible with the use of 3DUS; (2) a clavicular fracture was identified in utero with combined high-resolution two-dimensional and 3DUS; and (3) although absence of the nasal bones is most commonly observed in fetuses with chromosomal disorders (e.g. trisomy 21 and trisomy 18), a careful examination of the skeleton should be considered in fetuses with absent nasal bones and a normal karyotype.

Adult↗