Different formulas, different thresholds and different performance-the prediction of macrosomia by ultrasound.

OBJECTIVE: The sonographic prediction of fetal macrosomia affects obstetrical decision regarding the timing and mode of delivery. We aimed to compare the accuracy of various formulas for prediction of macrosomia at different thresholds. STUDY DESIGN: This was a retrospective cohort study of singleton gestations at term, with fetal biometrical measurements taken up to 7 days prior to delivery (2007 to 2014). Sonographic estimated fetal weight was calculated using 20 previously published formulas. Macrosomia prediction was evaluated for every formula utilizing: (1) measures of accuracy (sensitivity, specificity and so on); (2) comparison of the systematic and random errors (SE and RE), and the proportion of estimates within 10% of actual birth weight for macrosomic and non-macrosomic neonates. Performance measurements were evaluated for different macrosomia thresholds: 4000, 4250 and 4500 g. Best performing formula for every threshold was defined as the one with the lowest Euclidean distance (=SQRT(SE2+RE2)). RESULTS: Out of 7977 women who met the inclusion criteria, 754 (9.4%) delivered a neonate weighing ⩾4000 g, 266 (3.3%) delivered a neonate weighing⩾4250 g and 75 (0.9%) delivered a neonate weighing⩾4500 g. Considerable variability was noted between the accuracy parameters of the different formulas, with Woo's formula integrating Abdominal circumference (AC) and femur length (FL) as the most sensitive formula with the highest negative predictive value for all thresholds and Woo's formula using AC, FL and biparietal diameter (BPD) as the most specific for all thresholds. The same formula also demonstrated the best overall accuracy. Regardless of threshold chosen, 80% or more of formulas demonstrated negative systematic error, meaning lower EFW than actual birthweight. As for the Euclidean distance, Hadlock's formula (AC, FL and BPD) ranked the highest for the 4000 and 4250 g thresholds, whereas Shepard's formula (AC and BPD) ranked the highest for the 4500 g threshold. CONCLUSION: Considerable variability exist between formulas for prediction of neonatal macrosomia. Formulas by Hadlock's and Shepard's utilizing AC, BPD±FL were most accurate for macrosomia prediction at 4000, 4250 and 4500 g thresholds, respectively.

A novel ciliopathic skull defect arising from excess neural crest.

The skull is essential for protecting the brain from damage, and birth defects involving disorganization of skull bones are common. However, the developmental trajectories and molecular etiologies by which many craniofacial phenotypes arise remain poorly understood. Here, we report a novel skull defect in ciliopathic Fuz mutant mice in which only a single bone pair encases the forebrain, instead of the usual paired frontal and parietal bones. Through genetic lineage analysis, we show that this defect stems from a massive expansion of the neural crest-derived frontal bone. This expansion occurs at the expense of the mesodermally-derived parietal bones, which are either severely reduced or absent. A similar, though less severe, phenotype was observed in Gli3 mutant mice, consistent with a role for Gli3 in cilia-mediated signaling. Excess crest has also been shown to drive defective palate morphogenesis in ciliopathic mice, and that defect is ameliorated by reduction of Fgf8 gene dosage. Strikingly, skull defects in Fuz mutant mice are also rescued by loss of one allele of fgf8, suggesting a potential route to therapy. In sum, this work is significant for revealing a novel skull defect with a previously un-described developmental etiology and for suggesting a common developmental origin for skull and palate defects in ciliopathies.

Prediction of Parturition Time in Queens using Radiography and Ultrasonography.

This study investigated the prediction of parturition in queens, as well as the effects of the queens' age and weight and the litter size on the accuracy of the prediction. A prospective study was performed in 24 purebred queens of 11 different breeds, all in normal body condition, using radiographic and ultrasonographic measurements of foetal femoral length (FL) and biparietal diameter (BPD) of fœtal skull that apply to different breeds. Pregnant queens with aborted or malformed foetuses were excluded. The examinations were performed up to three times during the second half of pregnancy; litter size was obtained with radiography, and FL and BPD measurements were taken of each foetus using both radiography and ultrasonography. The maximal FL and the transversal BPD were recorded for each foetus. Radiography showed the number of foetuses accurately but did not allow accurate prediction of time of parturition. However, ultrasonography did establish the best predictive model according to the data with the FL. This model corresponded to the formula Y = 37.864 - 0.193 × FL + 1.227 × W - 0.615 × LS - 0.832 × A using the FL (10(-1)  mm), litter size (LS, number of foetuses per queen) and maternal parameters (weight (W, kg) and age (A, years)). Time to parturition correlated positively with the queen's weight and negatively with her age (P < 0.01). The ultrasonographic FL associated with pregnancy and maternal factors appeared to be an accurate model to predict parturition.

Cellular and molecular characterization of a novel primary osteoblast culture from the vertebrate model organism Xenopus tropicalis.

Osteogenesis is the fundamental process by which bones are formed, maintained and regenerated. The osteoblasts deposit the bone mineralized matrix by secreting large amounts of extracellular proteins and by allowing the biochemical conditions for the nucleation of hydroxyapatite crystals. Normal bone formation requires a tight control of osteoblastic activity, and therefore, osteoblasts represent a major focus of interest in biomedical research. Several crucial features of osteogenesis can be readily recapitulated using murine, avian and fish primary and immortalized osteoblastic cultures. Here, we describe a novel and straightforward in vitro culture of primary osteoblasts from the amphibian Xenopus tropicalis, a major vertebrate model organism. X. tropicalis osteoblasts can readily be extracted from the frontoparietal bone of pre-metamorphosing tadpole skulls by series of gentle protease treatments. Such primary cultures efficiently proliferate and can conveniently be grown at room temperature, in the absence of CO2, on a variety of substrates. X. tropicalis primary osteoblasts express well-characterized genes known to be active during osteogenesis of teleost fish, chick, mouse and human. Upon differentiation, such cultures mineralize and activate DMP1, an osteocyte-specific gene. Importantly, X. tropicalis primary osteoblasts can be efficiently transfected and respond to the forced activation of the bone morphogenetic protein pathway by increasing their nuclear levels of phospho-Smad. Therefore, this novel primary culture is amenable to experimental manipulations and represents a valuable tool for improving our understanding of the complex network of molecular interactions that govern vertebrate bone formation.

Magnetic resonance imaging evaluation of fetal maxillary sinuses.

BACKGROUND AND OBJECTIVE: The growth of maxillary sinus is closely connected to the development of facial structures. However, its definition and reference standards on fetal magnetic resonance imaging (MRI) have not been analyzed so far. In this study, the objectives were to define and evaluate the fetal maxillary sinus (fMS) formation with MRI. METHODS: We reviewed T2-weighted coronal MRI images of 75 fetuses. The MRI features, time of appearance, and boundaries of fMS were defined. Craniocaudal and transverse diameters of both maxillary sinuses and bone biparietal diameters were measured and statistically evaluated. RESULTS: In 150 fMS site analysis, 91 fMSs were identified. The fMSs were visualized as a hyperintense structures on T2-weighted image above the tooth bud. It first appeared at the 22nd gestational week, and in 4% (3/75) of fetuses, there was unilateral development. Mean craniocaudal length was 2.84 mm (1.1-4.8 mm), and mean transverse diameter was 2.67 mm (1.5-4.2 mm). CONCLUSIONS: Magnetic resonance imaging features of fMS that should be sought for the assessment of craniofacial anatomy are identified in this study. Fetal maxillary sinuses can be observed as hyperintense structures on T2-weighted MRI images starting from 22 weeks of gestation. The growth of fMS follows a predictable course throughout gestation; however, the dimensions are larger than the previously reported ex vivo series.

Cephalometric investigation of craniomaxillofacial structures during the prenatal period: a cadaver study.

INTRODUCTION: We aimed to investigate the morphometric development of the cranial base and its related structures, and their growth rate changes from the ninth gestational week to full term in a large group of human fetuses. METHODS: We selected 203 (109 male, 94 female) fetuses between 9 and 40 weeks of gestation and without any external anomalies. From each fetus, standard lateral and posteroanterior cephalometric images were taken using a dental digital panoramic and cephalometric x-ray machine. Fourteen linear and 9 angular parameters were measured. RESULTS: The cranial base angle showed a statistically significant increase between the groups from only the second to the third trimester periods. The sagittal translation of the maxilla increased during the prenatal period, whereas the mandibular sagittal relation grew at a steady rate. The vertical plane angles of the maxilla and the mandible did not show any significant changes. The maxillary length to mandibular length ratio remained stable. CONCLUSIONS: The cranial base angle increased, especially in the second through the third trimesters. The maxilla and the mandible demonstrated different growth patterns in the sagittal direction. The findings of this study could be a guide for interpreting the relationships among the craniofacial structures.

Predicting the Parturition Date in Bitches of Different Body Weight by Ultrasonographic Measurements of Inner Chorionic Cavity Diameter and Biparietal Diameter.

Predicting the parturition date in dogs by taking ultrasonographic foetometry has opened interesting research areas of veterinary obstetrics. Recently developed calculation formulas of inner chorionic cavity diameter (ICC) and biparietal diameter (BP) are formulas by Luvoni and Grioni (2000). This study is one of the first reports referring to ICC and BP with the use of Luvoni and Grioni formulas for predicting the parturition time in dogs of different body weight in clinical practice conditions. The research material consists of 70 clinically healthy pregnant bitches of 27 breeds and cross-breeds. Bitches were divided into 4 groups according to their body weight. In each of the bitches, ultrasonographic examination of pregnancy was performed at least twice (ICC and BP measurements). Parturition dates for dogs with a body weight over 25 kg were calculated based on formulas intended for the group of medium dogs. It was caused by the lack of appropriate formulas for these groups of dogs. The predicting parturition dates were compared with the actual dates of delivery provided by the bitch owners. Generally, the results obtained in this study are very encouraging and similar or even better than those published by other authors using foetometric measurements. In our research, when comparing the effectiveness of predicting the delivery date based on foetometric formulas by Luvoni and Grioni (2000), it was proved that in all groups of dogs, even those over 25 kg, ICC and BP measurements at both accuracy levels were characterized similar reliability.

Biparietal diameter at 11-13 weeks' gestation in fetuses with open spina bifida.

OBJECTIVE: To ascertain the reported association between reduced biparietal diameter (BPD) at 11-13 weeks' gestation and open spina bifida and to investigate its predictive value in a single-center study. METHODS: This was a retrospective study of fetuses in which BPD was measured at 11-13 weeks' gestation, including 27 fetuses with isolated open spina bifida subsequently diagnosed at 16-24 weeks and 7775 unaffected controls. BPD values were converted into multiples of the expected median (MoM) after adjustment for crown-rump length and maternal characteristics. Multivariable logistic regression analysis was used to determine the maternal characteristics significantly associated with spina bifida. The performance of screening was determined by receiver-operating characteristics curve analysis. BPD values at 11-13 weeks' gestation were compared with those measured in the second trimester using Z-scores. RESULTS: BPD values at 11-13 weeks' gestation were below the 5(th) centile in 44.4% of cases of open spina bifida. In these fetuses, the median BPD MoM value was significantly smaller than that in the control group (0.930 vs 0.998 MoM; P < 0.0001). Multivariable logistic regression analysis showed a significant contribution from maternal age (P = 0.008) and BMI (P = 0.028) to the association between BPD MoM and spina bifida. The detection rate using BPD measurements in the first trimester was 55.6% with a false-positive rate of 11.6%. In fetuses with open spina bifida, the BPD Z-scores were significantly lower at 16-24 weeks compared to those recorded at 11-13 weeks (median, -1.71 (range, -3.98 to -0.20) vs -1.30 (-3.75 to 2.61); P = 0.006). CONCLUSION: Fetuses with open spina bifida have a smaller BPD in the first trimester. This observation may be useful in early screening. It is likely that a combination of maternal characteristics such as age and BMI, fetal BPD and maternal serum alpha-fetoprotein measured in the first trimester would provide a clinically useful screening test for open spina bifida.

Systematic review of methodology used in ultrasound studies aimed at creating charts of fetal size.

BACKGROUND: Reliable ultrasound charts are necessary for the prenatal assessment of fetal size, yet there is a wide variation of methodologies for the creation of such charts. OBJECTIVE: To evaluate the methodological quality of studies of fetal biometry using a set of predefined quality criteria of study design, statistical analysis and reporting methods. SEARCH STRATEGY: Electronic searches in MEDLINE, EMBASE and CINAHL, and references of retrieved articles. SELECTION CRITERIA: Observational studies whose primary aim was to create ultrasound size charts for bi-parietal diameter, head circumference, abdominal circumference and femur length in fetuses from singleton pregnancies. DATA COLLECTION AND ANALYSIS: Studies were scored against a predefined set of independently agreed methodological criteria and an overall quality score was given to each study. Multiple regression analysis between quality scores and study characteristics was performed. MAIN RESULTS: Eighty-three studies met the inclusion criteria. The highest potential for bias was noted in the following fields: 'Inclusion/exclusion criteria', as none of the studies defined a rigorous set of antenatal or fetal conditions which should be excluded from analysis; 'Ultrasound quality control measures', as no study demonstrated a comprehensive quality assurance strategy; and 'Sample size calculation', which was apparent in six studies only. On multiple regression analysis, there was a positive correlation between quality scores and year of publication: quality has improved with time, yet considerable heterogeneity in study methodology is still observed today. CONCLUSIONS: There is considerable methodological heterogeneity in studies of fetal biometry. Standardisation of methodologies is necessary in order to make correct interpretations and comparisons between different charts. A checklist of recommended methodologies is proposed.

Paleontological and developmental evidence resolve the homology and dual embryonic origin of a mammalian skull bone, the interparietal.

The homologies of mammalian skull elements are now fairly well established, except for the controversial interparietal bone. A previous experimental study reported an intriguing mixed origin of the interparietal: the medial portion being derived from the neural crest cells, whereas the lateral portion from the mesoderm. The evolutionary history of such mixed origin remains unresolved, and contradictory reports on the presence or absence and developmental patterns of the interparietal among mammals have complicated the question of its homology. Here we provide an alternative perspective on the evolutionary identity of the interparietal, based on a comprehensive study across more than 300 extinct and extant taxa, integrating embryological and paleontological data. Although the interparietal has been regarded as being lost in various lineages, our investigation on embryos demonstrates its presence in all extant mammalian "orders." The generally accepted paradigm has regarded the interparietal as consisting of two elements that are homologized to the postparietals of basal amniotes. The tabular bones have been postulated as being lost during the rise of modern mammals. However, our results demonstrate that the interparietal consists not of two but of four elements. We propose that the tabulars of basal amniotes are conserved as the lateral interparietal elements, which quickly fuse to the medial elements at the embryonic stage, and that the postparietals are homologous to the medial elements. Hence, the dual developmental origin of the mammalian interparietal can be explained as the evolutionary consequence of the fusion between the crest-derived "postparietals" and the mesoderm-derived "tabulars."

Atretic parietal cephalocele associated with sinus pericranii: embryological consideration.

We report a case of atretic parietal cephalocele with a persistent parietal falcine sinus and partial absence of the straight sinus. The direct puncture angiographic study demonstrated that there was a major venous channel through the parietal skull defect. From the embryological point of view, this association may provide us with possible pathoetiologic evidence of congenital sinus pericranii is one of the alternative venous drainage pathways to compensate venous outflow in the cases of intracranial developmental anomalies.

Intrapartum sonographic imaging of fetal head asynclitism.

Anterior asynclitism was suspected on digital examination of a laboring woman with late arrest of dilatation and no evidence of fetal head progression. Clinical examination revealed a fixed non-engaged fetal head (station −1), with a transverse posterior sagittal suture. A static three-dimensional volume was obtained by translabial ultrasound, offline analysis of which confirmed the clinical diagnosis of anterior asynclitism. Owing to the posterior twisting of the head towards the sacrum, the midline echo could only be obtained by cutting the volume with an oblique line, the direction of which was not perpendicular to the pubis as expected in cases of synclitic head. The sonographic appearance of the midline echo approaching the sacrum in a non-engaged transverse fetal head strongly supports the clinical suspicion of anterior asynclitism.

Advantages of the population-based approach to pregnancy dating: results from 23,020 ultrasound examinations.

OBJECTIVE: To confirm the results from two previous evaluations of term prediction models, including two sample-based models and one population-based model, in a third population. METHODS: In a study population of 23,020 second-trimester ultrasound examinations, data were prospectively collected and registered over the period 1988-2009. Three different models for ultrasonically estimated date of delivery were applied to the measurements of fetal biparietal diameter (BPD) and two models were applied to the femur length (FL) measurements; the resulting term estimations were compared with the actual time of delivery. The difference between the actual and the predicted dates of delivery (the median bias) was calculated for each of the models, for three BPD/FL-measurement subgroups and for the study population as a whole. RESULTS: For the population-based model, the median bias was + 0.4 days for the BPD-based predictions and - 0.4 days for the FL-based predictions, and the biases were stable over the inclusion ranges. The biases of the two traditional models varied with the size of the fetus at examination; median biases were - 0.87 and + 2.2 days, respectively, with extremes - 4.2 and + 4.8 days for the BPD-based predictions, and the median bias was + 1.72 days with range - 0.8 to + 4.5 days for FL-based predictions. The disagreement between the two sample-based models was never less than 2 days for the BPD-based predictions. CONCLUSION: This study confirms the results from previous studies; median biases were negligible with term predictions from the population-based model, while those from the traditional models varied substantially. The biases, which have clinical implications, seem inevitable with the sample-based models, which, even if overall biases were removed, will perform unsatisfactorily.

A new population-based term prediction model vs. two traditional sample-based models: validation on 9046 ultrasound examinations.

OBJECTIVES: To compare results of predictions of date of delivery from a new population-based model with those from two traditional regression models. METHODS: We included 9046 fetal biparietal diameter (BPD) measurements and 8776 femur length (FL) measurements from the routine ultrasound examinations at Stavanger University Hospital between 2001 and 2007. The prediction models to be validated were applied to the data, and the resulting predictions were compared with the actual time of the subsequent deliveries. The primary measure was the median bias (the difference between the true and the predicted date of delivery), calculated for each method, for the study population as a whole and for three subgroups of BPD/FL measurements. We also assessed the proportion of births within ± 14 days of the predicted day, and rates of preterm and post-term deliveries, which were regarded as secondary measures. RESULTS: For the population-based model, the median bias was -0.15 days (95% confidence interval (CI), -0.43 to 0.12) for the BPD-based, and -0.48 days (95% CI, -0.86 to -0.46) for the FL-based predictions, and both biases were stable over the inclusion ranges. The biases of the traditional regression models varied, depending on the fetal size at the time of the examination; the extremes were -3.2 and + 4.5 days for the BPD-based, and -1.0 and + 5.0 days for the FL-based predictions. CONCLUSIONS: The overall biases, as well as the biases for the subgroups, were all smaller with the population-based model than with the traditional regression models, which exhibited substantial biases in some BPD and FL subcategories. For the population-based model, the FL-based predictions were in accordance with the BPD-based predictions.

Weight estimation for low birth weight fetuses and macrosomic fetuses in Chinese population.

OBJECTIVE: Compared with normal birth weight fetuses (2,500-4,000 g), accurate fetal weight estimation for fetuses with low or excessive weight is considered more important for fetal compromise prediction and labor management. New formulas were developed to estimate weight for low birth weight (LBW) fetuses and macrosomic fetuses, respectively. METHODS: A total of 523 fetuses with birth weight less than 2,500 g, 652 fetuses with normal birth weight, and 239 fetuses with birth weight more than 4,000 g were included in the study. As much as 25 existing formulas which incorporate regularly defined fetal measurements were evaluated and compared. Performance evaluation of existing formulas showed that no formulas can provide consistently accurate weight estimation both for LBW fetuses and macrosomic fetuses. A total of 1,034 cases were utilized to generate an overall regression formula. If the pre-estimated weight fell into the suspicious LBW and macrosomia range, the value was then updated by using the new regression formulas for LBW fetuses and macrosomic fetuses. As the training group, 262 LBW fetuses and 120 macrosomic fetuses were employed in a stepwise linear regression to obtain two update regression formulas for suspicious LBW fetuses and macrosomic fetuses. As the validation group, another 261 LBW fetuses and 119 macrosomic fetuses were assessed. RESULTS: The new overall formula has the form of Log(10)BW = 0.180(HC) + 0.00628(AC) - 0.00318(HC)(2) + 0.00173(AC)(FL) + 0.0000430(BPD)(HC)(2). The update formula for suspicious LBW fetuses is LnBW = 1.470(BPD) + 0.0169(HC) - 0.0873(BPD)(2) + 0.00518(AC)(FL) and for macrosomic fetuses is Log(10)BW = 0.730(BPD) - 0.0375(BPD)(2) + 0.000264(AC)(FL). For LBW fetuses, the new method gave 7.6 ± 209.0 (g) of estimation error and 8.3 ± 7.8 (%) of absolute percentage error, while the best existing formula provided -0.7 ± 226.0 (g) and 9.1 ± 8.3 (%). With the new method, 71.3% of estimates fell within ±10% of the actual birth weight, while the best existing formula gave 65.5%. For macrosomic fetuses, the new method gave -87.9 ± 231.0 (g) of estimation error and 4.4 ± 3.9 (%) of absolute percentage error, while the best existing formula provided 115.6 ± 345.1 (g) and 6.8 ± 5.4 (%). With the new method, 89.1% of estimates fell within ±10% of the actual birth weight, while the best existing formula gave 75.6%. CONCLUSIONS: To improve the weight estimation accuracy for low or excessive weight fetuses, separate formulas are necessary. The new method provides significant improvement on fetal weight estimation for LBW fetuses and macrosomic fetuses.

Biases of traditional term prediction models: results from different sample-based models evaluated on 41 343 ultrasound examinations.

OBJECTIVE: To evaluate two Norwegian traditional, sample-based term prediction models as applied to the data from a large population-based registry. The two models were also compared with an established German model. METHODS: Our database included information from 41 343 non-selected ultrasound scans registered over the years 1987-2005. The prediction models were applied to measurements from the ultrasound examinations, and the resulting term predictions were compared with the actual times of the deliveries. The median bias (the difference between the true and the predicted date of delivery) was calculated for each model, both for the study population as a whole and for subgroups of measurements of biparietal diameter (BPD) and femur length (FL). Secondary measures, i.e. proportion of births within ± 14 days and the rates of preterm and post-term deliveries, were also assessed. RESULTS: The analyses showed that the models had significant biases, predicting delivery date either too late or too early. For each model the size of the bias varied, depending on the fetal size at the time of the examination; the extremes were minus 4 and plus 4 days for the BPD-based predictions. There were similar results with the FL-based predictions. CONCLUSION: Term predictions made with traditional sample-based models had significant biases that varied over each method's measurement range. These models have important shortcomings, probably because of strict selection criteria in the process of constructing the models, and because the methods primarily aim at estimating the last menstrual period-based day of conception, not the day of birth.

Tgfbr2 is required for development of the skull vault.

Transforming growth factor beta (TGFbeta) is known to play important roles in multiple developmental processes. One of the main functions is in skeletal development. Our previous studies demonstrated that loss of Tgfbr2 in Prx1Cre-expressing limb mesenchyme results in defects in the long bones and joints of mice. Here we show that loss of Tgfbr2 also results in defects in the development of the skull vault indicating Tgfbr2 has a critical role in intramembranous bone formation as well as endochondral bone formation. Mutant mice did not survive after birth and demonstrated an open skull. The first signs of skull defects were observed at E14.5 day. Prx1Cre(+)/Tgfbr2(f/f) embryos showed significantly reduced cell proliferation in the developing mesenchyme of the skull by E14.5 day without any detectable alteration in apoptosis suggesting that reduced cell proliferation in Prx1Cre(+)/Tgfbr2(f/f) embryos was at least partially responsible for the defects observed. Immunofluorescent staining showed a significant reduction in the expression of Runx2/Cbfa1 and Osterix/Sp7 in Prx1Cre(+)/Tgfbr2(f/f) embryos suggesting that osteoblast differentiation was also altered in Prx1Cre(+)/Tgfbr2(f/f) embryos. To distinguish between the effects of losing Tgfbr2 on mesenchymal proliferation versus osteoblast differentiation, osteoprogenitor cells from the skulls of Tgfbr2(f/f) embryos were cultured under conditions of high cell density and Tgfbr2 was deleted from the cells using Adeno-Cre virus. RT-PCR analysis showed that the mRNA level of Runx2 and Osterix as well as Dlx5 and Msx2 were down-regulated in Tgfbr2-deleted cultures compared to control cultures indicating that Tgfbr2 regulates osteoblast differentiation independent of regulating proliferation. Together, these results suggest that Tgfbr2 is required for normal development of the skull.