Prenatal Ultrasound Measurements Research Articles

FetalAI: A deep learning web-based application for predicting birthweight from prenatal ultrasound measurements

FetalAI is a web-based application that utilizes a longitudinal learning procedure that integrates data augmentation and deep learning as back-end, with a purpose of predicting an newborn’s projected birthweights and the associated risks of excessive fetal growth conditions, including large-for-gestational-age (LGA) and macrosomia. This article provides an end-to-end overview of FetalAI’s development process, which includes data sourcing and preprocessing, back-end model design and training, application output interpretation, and user interactions. We begin by describing the original training data sources and their mathematical structures. We then outline the data engineering pipeline that acquires and pre-processes user input. After data sourcing and pre-processing, we provide details on the back-end model, which applies mixed-effects models for data augmentation and pre-trained recurrent neural networks (RNNs) to forecast birthweight sequences. After back-end, we discuss the front-end development of FetalAI, with an emphasis on creating the graphical user interface (GUI) using Streamlit and the application’s ability to handle corner cases and anomalous inputs. Our article concludes by highlighting the key functionalities and potential use cases of FetalAI, as well as outlining future directions for research and development in this domain. FetalAI represents a significant step forward in the application of deep learning techniques to improve prenatal care and support clinical decision-making.

Bias in the prenatal lung measurements in fetal congenital diaphragmatic hernia with intrauterine growth restriction.

The failure of a fetus to develop to its full potential due to maternal or placental factors is known as intrauterine growth restriction (IUGR). Fetal head growth is usually preserved in that situation producing a potential discordance between head and body size. Our goal is to discover if IUGR has an impact on the prenatal ultrasound measurements taken to assess pulmonary development in congenital diaphragmatic hernia (CDH). A retrospective chart review (IRB#2017-6361) was performed on all prenatally diagnosed CDH patients from 2007 to 2016. Patient demographics, fetal and neonatal anthropometric measurements, and fetal lung parameters were the main subjects of the data that were gathered. Fetal growth was assessed by the curves based on US data by Olsen etal. and by Peleg etal. Of 147 CDH patients, 19 (12.9 %) patients were diagnosed with IUGR before the 30th gestational week while there were 20 (13.6 %) patients after the 30th gestational week. Patients with IUGR and the observed-to-expected lung-to-head ratio (O/E LHR) less than 25 % had better survival rates both to discharge and date compared to non IUGR group (p=0.226, OR 2.25 95 % CI 0.60-1.08 and p=0.175, OR 2.40 95 % CI 0.66-1.17, respectively). Moreover, the ECMO need of the patients who had IUGR and O/E LHR less than 25 % was significantly less than the patients without IUGR (38.5 vs. 80.0 %, p=0.005). This study confirms that the intrauterine measurements to predict pulmonary hypoplasia in CDH patients are misleading in the presence of IUGR and cause an overestimation.

Gastroschisis ultrasound bowel characteristics demonstrate minimal impact on perinatal outcomes.

Bowel dilation and bowel wall thickness are common prenatal ultrasound measurements for fetuses with gastroschisis. Data regarding antenatal sonographic bowel findings and postnatal outcomes are conflicting. Our objective was to evaluate the impact of in utero bowel measurements on perinatal outcomes in gastroschisis pregnancies. Retrospective cohort study of 116 pregnancies complicated by gastroschisis between 2011 and 2020. We reviewed ultrasounds documenting fetal bowel measurements. To evaluate the association of these measurements with antepartum and delivery outcomes, we ran logistic and linear models using generalized estimating equations. Eleven perinatal outcomes reached statistical significance, although with minimal clinical impact given small magnitude of effect. Intra-abdominal bowel dilation was associated with a 0.5 week decrease in delivery gestational age (GA) (95% CI -0.07, -0.03) and a 6.93 g increase in birth weight (95% CI 1.54, 28.73). Intra-abdominal bowel wall thickness was associated with later GA of non-stress test (NST) start of 0.22 weeks (95% CI 0.07, 0.37), increased delivery GA of 0.08 weeks (95% CI 0.02, 0.15), 0.006 decrease in umbilical artery (UA) pH (95% CI -0.009, -0.003), 0.26 increase in UA base deficit (95% CI 0.09, 0.43), and decreased odds of cesarean delivery (OR = 0.83, 95% CI 0.70, 0.99). Extra-abdominal bowel wall thickness was associated with a 0.1 increase in UA base deficit (95% CI 0.02, 0.19) and a 0.05 increase in 5-min APGAR score (95% CI 0.01, 0.09). Stomach cross-section was associated with a 0.01 week decrease in delivery GA (95% CI -0.02, -0.001) and increased odds of receiving betamethasone (OR = 1.02, 95% CI 1.01, 1.04). In utero bowel characteristics reached statistical significance for several outcomes, but with minimal meaningful clinical differences in outcomes.

Analysis of factors associated with the umbilical cord pitch value by ultrasound measurement in late pregnancy

BackgroundThis study aimed to investigate the factors associated with the antenatal umbilical cord pitch value by ultrasound measurement in late pregnancy. We investigated the factors associated with the umbilical cord pitch value under prenatal ultrasound measurement.MethodsThis study included 528 pregnant women who underwent routine antenatal ultrasound examinations in Ningbo Women and Children’s Hospital from December 2020 to August 2021. Their umbilical cord pitch values and diameter, Wharton’s jelly thickness, amniotic fluid indexes, umbilical artery blood flow parameters, and other relevant data, such as ages and gestational ages, were measured. Information about delivery methods, placenta, umbilical cord, and neonatal weight were recorded during follow-up. Statistical analysis was performed on the above data, and the factors associated with the pitch values were analyzed by linear regression.ResultsThis study revealed that cord torsion (p < 0.001, 95% confidence interval [CI]=-34.81 to -19.01), cord entanglement (p < 0.001, 95% CI = 10.71 to 20.11), thickening of Wharton’s jelly (p = 0.001, 95% CI = 5.39 to 20.24), and cord edema (p = 0.015, 95%CI = 2.09 to 19.44), gestational age (p = 0.024, 95%CI = 0.14 to 1.89), age of pregnant woman (p = 0.009, 95%CI= -1.15 to -0.16), and neonatal weight (p = 0.011, 95%CI = 0.002 to 0.012) were significantly correlated with the pitch values.ConclusionThe umbilical cord pitch value significantly correlated with cord entanglement, cord torsion, cord edema, Wharton’s jelly thickening, gestational age, age of the pregnant woman, and neonatal weight. Notably, the pitch value by prenatal ultrasound measurement is predictive of cord morphological abnormalities such as cord entanglement, cord torsion, cord edema, and Wharton’s jelly thickening.

Fetal growth trajectories of babies born large-for-gestational age in the LIFECODES Fetal Growth Study

Babies born large-for-gestational age have an increased risk of adverse health outcomes, including birth injuries, childhood obesity, and cardiometabolic disorders. However, little work has been done to characterize patterns of fetal growth among large-for-gestational age births, which may further elucidate high- and low-risk subgroups. This study aimed to identify subgroups of large-for-gestational age births based on trajectories of fetal growth derived from prenatal ultrasound measurements and explore differences in sociodemographic, pregnancy, and birth outcome characteristics across subgroups. This study identified and described trajectories of fetal growth among large-for-gestational age births (n=235) in the LIFECODES Fetal Growth Study. Ultrasound measurements of fetal growth in middle to late pregnancy were abstracted from health records. Group-based multi-trajectory modeling was applied to measurements of head circumference, abdominal circumference, and femur length z-scores to identify multivariate trajectories of fetal growth. Moreover, sociodemographic variables, pregnancy characteristics, and birth outcomes based on trajectory membership were summarized. This study identified 4 multivariate trajectories of fetal growth among large-for-gestational age births: catch-up growth (n=28), proportional abdominal circumference-to-femur length growth (n=67), disproportional abdominal circumference-to-femur length growth (n=96), and consistently large (n=44). Fetuses in the "catch-up growth" group exhibited small relative sizes in midpregnancy (ie, below average head circumference, abdominal circumference, and femur length z-scores) and large relative sizes in late pregnancy. Growth among these births was driven by increases in relative abdominal circumference and head circumference sizes. Participants who delivered births assigned to this group were less likely to have normal glucose control (40% vs 65%-75%) and more likely to have pregestational diabetes mellitus (36% vs 10%-17%) than other large-for-gestational age subgroups. In addition, the babies in this trajectory group were more likely to have macrosomia (86% vs 67%-73%) and to be admitted to the neonatal intensive care unit (32% vs 14%-21%) than other large-for-gestational age subgroups. In contrast, babies in the "consistently large" group had the largest relative size for all growth parameters throughout gestation and experienced a lower risk of adverse birth outcomes than other large-for-gestational age subgroups. This study characterized several trajectories of fetal growth among large-for-gestational age births, which were related to different pregnancy characteristics and the distribution of adverse birth outcomes. Although the number of individuals within some trajectories was small, a subgroup that exhibited a catch-up growth phenotype during gestation was identified, which may be uniquely associated with exposure to pregestational diabetes mellitus and a higher risk of admission to the neonatal intensive care unit. These results have highlighted that the risk of adverse outcomes may not be evenly distributed across all large-for-gestational age births.

Prenatal ultrasound measurements of mild congenital pulmonary airway malformation and long-term prognosis: A retrospective cohort study.

To investigate the relationship between mild congenital pulmonary airway malformation (CPAM) and its long-term prognosis in childhood and to explore whether surgery is necessary. We conducted a retrospective cohort of fetuses with mild CPAM diagnosed prenatally with available long-term outcomes in childhood from 2004 to 2016. The patients were divided into two groups according to the fetal CPAM-to-volume ratio (CVR) of less than 1.0 and 1.0-1.6. The primary outcome was a postnatal composite outcome including CPAM-associated respiratory symptoms and surgical resection of the lesion. The secondary outcomes included neonatal asphyxia, perinatal morbidity and mortality. Forty-two fetuses were identified as having CVR <1.0 or CVR-1.0-1.6 respectively (n=37 vs n=5; 88.1% vs 11.9%), with the median duration of follow up 2.15years (0.3-10.8years). Of 42 patients, 32 (76%) remained asymptomatic without recurrent respiratory symptoms or surgical resection; the other 10 with CVR <1.0 had respiratory symptoms. Of 10 symptomatic cases, five recovered after expectant treatment, and five underwent resection, for an increase in lesion size and recurrent respiratory infection. Patients with CVR <1.0 still need to be closely observed after birth. Conservative management is a reasonable option in asymptomatic cases, but surgery might be necessary in some.

Factors Affecting Ultrasonographic Fetal Weight Estimation Accuracy in Low Birth Weight Newborns

Objective: To investigate the accuracy of fetal weight estimation made by the last prenatal ultrasound measurement in low birth weight newborns (&lt;2500 g). Study Design: A total of 1082 women were evaluated in this retrospective cohort study. Demographic and clinical information of the mother and newborn and obstetric ultrasonography measurements and findings performed in the last week before birth were recorded. Accuracy of fetal weight estimation and parameters affecting it was investigated. Results: Accurate estimation rates were lower in the term compared to the preterm delivery group; and in the SGA group compared to the AGA group (respectively, p=0.016, p=0.032). Accurate estimation rates (p=0.182) were comparable between the 500-1500 g and 1501-2500 g subgroups. The multiple linear regression analysis showed that gestational age at birth, birth weight, examination during labor, and duration between examination to delivery were statistically significant for the accurate estimation(p=0.001) Conclusions: Accurate estimation rates were lower in the term compared to the preterm delivery group, and in the SGA group compared to the AGA group. The factors affecting accurate estimation were found to be gestational age at birth, birth weight, examination during labor, and duration between examination to delivery.Keywords: Accurate estimation rate, Duration between examination to delivery, Examination during

Two-Dash Line: A New Approach for Prenatal Ultrasound Measurement of Iliac and Ischial Bones to Estimate Gestational Age.

There has been a dearth of an accurate and reliable method for the measurement of fetal pelvic bones. In this study, we describe a novel, easy-to-use method for ischial and iliac bone measurement in fetal ultrasound scanning. This prospective cross-sectional study was performed on 1179 pregnant women at 12 to 40 weeks of an uneventful gestation. Pelvic biometric indices, including the length of the ilium and ischium, were measured by a novel and easy method. Then data were analyzed by regression models to develop a formula for gestational age (GA) estimation based on pelvic bones. The approximate ossification time of the ischium was determined to range between the 13th and 20th gestational weeks. We calculated 3 formulas using linear regression models: formula 1, GA (days)=92.563 + (11.604 × ischial length); formula 2, GA (days)=57.006 + (7.819 × iliac length); and formula 3, GA (days)=65.809 + (5.610 × iliac length) + (3.431 × ischial length). The 2-dash line method can contribute to efficient and precise ultrasound measurement of the ilium and ischium in pelvic biometry of the fetus.

Prenatal Ultrasound Measurement of Fetal Stomach Size Is Predictive of Postnatal Development of GERD in Isolated Cleft Lip and/or Palate.

To determine whether prenatal ultrasound measurement of fetal stomach size, as a surrogate marker of fetal swallowing, is predictive of postnatal development of gastroesophageal reflux disease (GERD) in cases of isolated cleft lip and/or palate (CL/P). This is a retrospective case-control study. The outcome of interest is postnatal diagnosis of GERD in isolated CL/P. The exposure of interest is prenatal stomach size measurement by ultrasound. The study population was selected from an academic, tertiary care center between 2003 and 2011. Cases were neonates undergoing CL/P repair during the study period. Cases with other known structural or chromosomal abnormalities were excluded. Controls were contemporary, nondiabetic neonates that matched gestational age (within one week) to cases. Each case measurement was matched ∼1:2 with control measurement. None. The primary outcome was difference in mean prenatal ultrasound measurement of fetal stomach size between cases and controls. We hypothesized that patients with postnatal development of GERD would have smaller mean fetal stomach size. There were 32 cases including 19 patients with unilateral cleft lip and palate, 8 with unilateral cleft lip, and 4 with bilateral cleft lip and palate. Cases were noted to have smaller mean anterior-posterior and transverse fetal stomach measurements as compared to controls. This was statistically significant from 16 to 21 weeks, 25 to 27 weeks, and 28 to 36 weeks (P < .01 for all). Prenatal ultrasound measurement of fetal stomach size as a surrogate marker of fetal swallowing is predictive of postnatal development of GERD in isolated CL/P.

Secondary Imaging Findings Aid in Prenatal Diagnosis and Characterization of Congenital Diaphragmatic Hernia: Role of an Abnormal Orientation of Vascular Structures and Gallbladder Position.

To determine whether an abnormal orientation of the abdominal or hepatic vasculature and an abnormal gallbladder position on prenatal ultrasound (US) imaging are associated with intrathoracic liver herniation and postnatal outcomes in cases of congenital diaphragmatic hernia (CDH). Children who underwent prenatal US examinations and postnatal CDH repair at our institution were eligible. Prenatal US images were reviewed, and the orientation of the superior mesenteric artery (SMA) and hepatic veins as well as gallbladder position were recorded. Findings were correlated with prenatal US measurements (lung-to-head ratio and calculated observed-to-expected lung-to-head ratio) and postnatal outcomes, including intrathoracic liver herniation, an extracorporeal membrane oxygenation (ECMO) requirement, and mortality. A total of 175 patients met inclusion criteria. The SMA was shown in 168 cases and had a cephalad orientation in 95.4% (161 of 168), which was not associated with outcome measures and represented bowel herniation. A cephalad orientation of the hepatic veins was identified in 52.6% (90 of 171) and was associated with intrathoracic liver herniation, an ECMO requirement, and mortality (P < .01). In right-sided CDH, the gallbladder was intrathoracic in 91.3% (21 of 23). In left-sided CDH, an abnormal gallbladder position was seen in 51.3% (76/152) and was associated with intrathoracic liver herniation, an ECMO requirement, mortality, and lower lung-to-head ratio and observed-to-expected lung-to-head ratio values. When combined, abnormal hepatic vein and gallbladder positions showed good sensitivity and specificity in predicting intrathoracic liver herniation (area under the curve, 0.93). Abnormal SMA, hepatic vein, and gallbladder positions can be used to improve prenatal characterization of CDH. Accurate depiction of these structures on prenatal US images may aid in patient counseling and postnatal management.

Predicting birth weight with conditionally linear transformation models.

Low and high birth weight (BW) are important risk factors for neonatal morbidity and mortality. Gynecologists must therefore accurately predict BW before delivery. Most prediction formulas for BW are based on prenatal ultrasound measurements carried out within one week prior to birth. Although successfully used in clinical practice, these formulas focus on point predictions of BW but do not systematically quantify uncertainty of the predictions, i.e. they result in estimates of the conditional mean of BW but do not deliver prediction intervals. To overcome this problem, we introduce conditionally linear transformation models (CLTMs) to predict BW. Instead of focusing only on the conditional mean, CLTMs model the whole conditional distribution function of BW given prenatal ultrasound parameters. Consequently, the CLTM approach delivers both point predictions of BW and fetus-specific prediction intervals. Prediction intervals constitute an easy-to-interpret measure of prediction accuracy and allow identification of fetuses subject to high prediction uncertainty. Using a data set of 8712 deliveries at the Perinatal Centre at the University Clinic Erlangen (Germany), we analyzed variants of CLTMs and compared them to standard linear regression estimation techniques used in the past and to quantile regression approaches. The best-performing CLTM variant was competitive with quantile regression and linear regression approaches in terms of conditional coverage and average length of the prediction intervals. We propose that CLTMs be used because they are able to account for possible heteroscedasticity, kurtosis, and skewness of the distribution of BWs.

Predicting gestational age using neonatal metabolic markers

BackgroundAccurate gestational age estimation is extremely important for clinical care decisions of the newborn as well as for perinatal health research. Although prenatal ultrasound dating is one of the most accurate methods for estimating gestational age, it is not feasible in all settings. Identifying novel and accurate methods for gestational age estimation at birth is important, particularly for surveillance of preterm birth rates in areas without routine ultrasound dating.ObjectiveWe hypothesized that metabolic and endocrine markers captured by routine newborn screening could improve gestational age estimation in the absence of prenatal ultrasound technology.Study DesignThis is a retrospective analysis of 230,013 newborn metabolic screening records collected by the Iowa Newborn Screening Program between 2004 and 2009. The data were randomly split into a model-building dataset (n = 153,342) and a model-testing dataset (n = 76,671). We performed multiple linear regression modeling with gestational age, in weeks, as the outcome measure. We examined 44 metabolites, including biomarkers of amino acid and fatty acid metabolism, thyroid-stimulating hormone, and 17-hydroxyprogesterone. The coefficient of determination (R2) and the root-mean-square error were used to evaluate models in the model-building dataset that were then tested in the model-testing dataset.ResultsThe newborn metabolic regression model consisted of 88 parameters, including the intercept, 37 metabolite measures, 29 squared metabolite measures, and 21 cubed metabolite measures. This model explained 52.8% of the variation in gestational age in the model-testing dataset. Gestational age was predicted within 1 week for 78% of the individuals and within 2 weeks of gestation for 95% of the individuals. This model yielded an area under the curve of 0.899 (95% confidence interval 0.895−0.903) in differentiating those born preterm (<37 weeks) from those born term (≥37 weeks). In the subset of infants born small-for-gestational age, the average difference between gestational ages predicted by the newborn metabolic model and the recorded gestational age was 1.5 weeks. In contrast, the average difference between gestational ages predicted by the model including only newborn weight and the recorded gestational age was 1.9 weeks. The estimated prevalence of preterm birth <37 weeks’ gestation in the subset of infants that were small for gestational age was 18.79% when the model including only newborn weight was used, over twice that of the actual prevalence of 9.20%. The newborn metabolic model underestimated the preterm birth prevalence at 6.94% but was closer to the prevalence based on the recorded gestational age than the model including only newborn weight.ConclusionsThe newborn metabolic profile, as derived from routine newborn screening markers, is an accurate method for estimating gestational age. In small-for-gestational age neonates, the newborn metabolic model predicts gestational age to a better degree than newborn weight alone. Newborn metabolic screening is a potentially effective method for population surveillance of preterm birth in the absence of prenatal ultrasound measurements or newborn weight.

The relation between viscero-abdominal disproportion and type of omphalocele closure

ObjectiveTo investigate the relation between prenatal ultrasound measurements of viscero-abdominal disproportion and the expected type of postnatal surgical closure of an omphalocele. Study designRetrospectively, 24 fetuses diagnosed with an isolated omphalocele in the 2nd trimester of pregnancy were selected (period 2003–2013). An image of the axial plane of the abdomen at the level of the defect was retrieved. The ratio of omphalocele circumference to abdominal circumference (OC/AC), and the ratio of defect diameter to abdominal diameter (DD/DA) were calculated. Prognostic outcome was primary closure. Sensitivity and specificity and the corresponding area under the ROC curve of these ratios were calculated as measurements of prognostic accuracy. ResultsPrimary closure was achieved in 15/24 cases. For the OC/AC-ratio a cut-off value of 0.82 successfully predicted outcome in 23/24 cases with an area under the ROC curve of 0.99. A cut-off value of 0.61 for the DD/DA-ratio successfully predicted type of closure in 20/24 cases with an area under the ROC curve of 0.88. In all cases without eviscerated liver tissue, the defect was primarily closed. ConclusionIn prenatal isolated omphalocele cases, the OC/AC-ratio is better at predicting postnatal surgical closure than the DD/DA-ratio and can be used as a prognostic tool for expected type of closure in the 2nd trimester of pregnancy.

Prediction of pulmonary hypoplasia in mid‐trimester preterm prelabor rupture of membranes: research or clinical practice?

Prediction of pulmonary hypoplasia in mid‐trimester preterm prelabor rupture of membranes: research or clinical practice?

P08.11: Correlation between prenatal ultrasound measurements and newborn outcome in the free loop of the small bowel in gastroschisis. Part II 2008–2010

Gastrochisis is an abdominal wall anterior defect that involved extrusion of fetal intestines. Occur in 0.13 to 1.4 per 10.000 live births. Review from the ultrasound literature report small bowel diameter over 11 mm to predict adverse neonatal outcome. This study want to add to our 12 gastrosquisis in the last study 8 new more between 2008–2010 to correlated our findings. Data's from 8 fetuses that had gastroschisis. Ultrasound report was made by taking measurements of the free loop in the small bowel (length and the anteroposterior diameter) and 3D images. All studies were performed using an 3700 ALOKA ultrasound system. Data's were analyze in computer statically program (excel 2007). The mean of the length in the free loop was 46 mm the low value was 20 mm and the maximum value of the free loop was 60 mm. The mean of the anteroposterior diameter was 16 mm. The low value was 13.7 mm and the maximum value of the free loop in the anteroposterior diameter was 20 mm. Mean fetal weigh 2315 grams. Mean gestational age to delivery 35 weeks. Thirty seven point five of the newborn had complications 37.5% (obstruction, appendicitis). Mean overall length stay of intensive unit care was 17 days. Measurement of the free loop in the small bowel is a good marker to prevent ischemia (60 mm per 16 mm). Preterm delivery gives better outcome to the newborn with Gastroschisis after 34 weeks and the mean overall length stay in the intensive unit care if half in comparison with the last report. We need more data's to see the best gestational age to delivery fetus with gastroschisis without complications.

OP13.06: Correlation between prenatal ultrasound measurements and newborn outcome in the free loop of the small bowel in gastroschisis

OP13.06: Correlation between prenatal ultrasound measurements and newborn outcome in the free loop of the small bowel in gastroschisis

Predicting late-onset growth abnormalities using growth velocity between trimesters

Objectives. To determine whether growth velocity parameters derived from routine prenatal ultrasound measurements at first, second and third trimester can identify normal growth at term as well as late-onset growth abnormalities.Material and methods. Longitudinal study of fetal growth in normal singleton pregnancies with three normal ultrasound examinations and delivered at term. Fetuses were classified into 3 groups ( < 10th percentile, 10–90th percentile, > 90th percentile) based on birth weight. Multiple regression on birth weight classification was used to build up a prediction equation of fetal growth potential (FGP) based on fetal biometry and fetal growth velocity parameters between ultrasound examinations. Best cut-off value for FGP predicting growth restriction and macrosomia were defined.Results. 356 pregnancies were included. Fetal biometry growth velocities between examinations were calculated for all measurements. Using best cut-off values, the estimated sensitivity, specificity and odds ratio were: 60% [44;74], 91%[89;92] and 14.55 [6.30;33.98] and 53% [36;69], 89%[88;91] and 10 [4.27;23.49] for the prediction of growth restriction and macrosomia, respectively.Discussion. Fetal growth potential can be derived and calculated from standard ultrasound measurements. It can improve identification of these fetuses at risk for late-onset growth abnormalities and their related morbidity.

Diagnostic accuracy of fetal renal pelvis anteroposterior diameter as a predictor of uropathy: a prospective study

The purpose of this study was to assess the accuracy of prenatal ultrasound measurement of anteroposterior renal pelvis diameter (APD) to discriminate between significant uropathy and idiopathic renal pelvis dilatation. One-hundred-and-three neonates who were found to have fetal renal pelvis dilatation, defined as presence of an APD > or = 5 mm, underwent systematic investigation for uropathies and were prospectively followed. An ultrasound scan was performed after the first week of postnatal life and all infants underwent a voiding cystourethrogram. Neonates with an APD larger than 10 mm underwent renal scintigraphy. Ultrasound scans, clinical examination and laboratory reviews were scheduled at 6-month intervals. Receiver-operating characteristics (ROC) curves were constructed to determine the best cut-offs for APD to identify renal units with significant uropathy as well as those requiring surgical intervention. Significant uropathy was defined as the presence of well-established urinary tract abnormalities or when there was abnormal renal scintigraphy. The estimated area under the curve for APD was 0.900 (95% CI, 0.841-0.942) indicating excellent power to discriminate between idiopathic pelvis dilatation and significant uropathy. The sensitivity and specificity for the 7.5 mm cut-off point were 97.9% and 40.6%, respectively. To identify infants who required surgical intervention, the calculated area under the curve was 0.953 (95% CI, 0.908-0.980). Our results suggest that measurement of APD is an excellent test to identify fetuses with significant uropathy, as well as those requiring postnatal intervention.

Handbook of normal physical measurements

Introduction Measurement Proportional growth and normal variants Height and length Weight Head circumference Craniofacies Limbs Chest and trunk Genitalia Skin and hair Dermatoglyphics and trochoglyphics Use of radiographs Developmental data Prenatal ultrasound measurements Postmortem organ weights Special measurements for special conditions Approach to the child with a dysmorphic syndrome Glossary.