Measurements Of Fetal Head Circumference Research Articles

Artificial Intelligence-Based Estimation of Fetal Head Circumference With Biparietal and Occipitofrontal Diameters Using Two-Dimensional Ultrasound Images

Abstract One of the most essential biometrics for measuring fetal growth during prenatal ultrasound exams is the head circumference (HC). However, manual measurement of this biometric by doctors often needs substantial experience. Manual measurement of fetal head circumference during prenatal ultrasound exams requires significant expertise, posing limitations in accuracy and consistency, which can impact clinical decision-making and fetal health assessments. We developed a state-of-the-art image processing algorithm that utilizes biometry and segmented images and employed a fast ellipse fitting method to measure the HC, head orientation (angle) along with biparietal (BPD), and occipitofrontal (OFD) diameter automatically. Our approach offers automation and precision in measuring fetal biometrics, surpassing the limitations of manual measurement by ensuring consistent and accurate assessments, thus enhancing clinical efficiency and facilitating timely interventions for optimal fetal health management. Additionally, to the best of our knowledge, this is the first work that adopts a segmented image from any model or technique and provides significant fetal parameters during ultrasonography in a single shot. The suggested technique is lightweight, real-time, and easily integrate with any segmentation model or technique. We have used three well-known segmentation models for demonstration and compared their performance using dice scores as an evaluation parameter. Among the three, HRNet shows the best results with an average dice score of 0.96; due to the high dice score, we have chosen HRNet over the other two models and proceeded further and implemented our novel algorithm on that to predict the required fetal key measurements. The findings of this study benefit prenatal care by enhancing the accuracy and efficiency of fetal biometric measurements, thereby facilitating improved clinical decision-making and optimizing fetal health assessments.

Differing prevalence of microcephaly and macrocephaly in male and female fetuses.

To compare the proportion of female and male fetuses classified as microcephalic (head circumference [HC] < 3rd percentile) and macrocephalic (>97th percentile) by commonly used sex-neutral growth curves. For fetuses evaluated at a single center, we retrospectively determined the percentile of the first fetal HC measurement between 16 and 0/7 and 21-6/7 weeks using the Hadlock, Intergrowth-21st, and NICHD growth curves. The association between sex and the likelihood of being classified as microcephalic or macrocephalic was evaluated with logistic regression. Female fetuses (n = 3,006) were more likely than male fetuses (n = 3,186) to be classified as microcephalic using the Hadlock (0.4% male, 1.4% female; odds ratio female vs. male 3.7, 95% CI [1.9, 7.0], p < 0.001), Intergrowth-21st (0.5% male, 1.6% female; odds ratio female vs. male 3.4, 95% CI [1.9, 6.1], p < 0.001), and NICHD (0.3% male, 1.6% female; odds ratio female vs. male 5.6, 95% CI [2.7, 11.5], p < 0.001) curves. Male fetuses were more likely than female fetuses to be classified as macrocephalic using the Intergrowth-21st (6.0% male, 1.5% female; odds ratio male vs. female 4.3, 95% CI [3.1, 6.0], p < 0.001) and NICHD (4.7% male, 1.0% female; odds ratio male vs. female 5.1, 95% CI [3.4, 7.6], p < 0.001) curves. Very low proportions of fetuses were classified as macrocephalic using the Hadlock curves (0.2% male, < 0.1% female; odds ratio male vs. female 6.6, 95% CI [0.8, 52.6]). Female fetuses were more likely to be classified as microcephalic, and male fetuses were more likely to be classified as macrocephalic. Sex-specific fetal head circumference growth curves could improve interpretation of fetal head circumference measurements, potentially decreasing over- and under-diagnosis of microcephaly and macrocephaly based on sex, therefore improving guidance for clinical decisions. Additionally, the overall prevalence of atypical head size varied using three growth curves, with the NICHD and Intergrowth-21st curves fitting our population better than the Hadlock curves. The choice of fetal head circumference growth curves may substantially impact clinical care.

Automatic measurement of fetal head circumference using a novel GCN-assisted deep convolutional network

The growth of the fetus can be effectively monitored by measuring the fetal head circumference (HC) in ultrasound images. Moreover, it is the key to assessing the fetus's health. Ultrasound fetal head image boundary is blurred. The ultrasound sound shadow results in a partial absence of the skull in the image. The amniotic fluid and uterine wall form a structure similar to the head texture and grayscale. All these factors result in challenges to ultrasound fetal head edge detection. The new convolutional neural network (CNN) named GAC Net was proposed in this paper, which can effectively solve the above problems. GAC Net is an end-to-end network model constructed by the encoder and decoder. In order to suppress the interference of ultrasound image quality defects on the HC measurement, the graph convolutional network (GCN) module was added to the connection channel between the encoder and the decoder. The new attention mechanism enhanced the network's ability to perceive border areas. Experiments were performed on the HC18 fetal head ultrasound image data set. The following objective evaluation indicators were calculated, including the Hausdorff distance (HD), the absolute difference (AD), the difference (DF), and the Dice similarity coefficient (DSC) of head circumference. Experimental results showed that GAC-Net had an HD of 1.22 ± 0.71 mm, an AD of 1.75 ± 1.71 mm, a DF of 0.19 ± 2.32 mm, and a DSC of 98.21 ± 1.16%. The overall performance of the proposed algorithm exceeded the state-of-the-art methods, which fully proved the effectiveness of the GAC Net presented in this paper.

A new sonographic approach to predict cephalo-pelvic disproportion: the HC/OC ratio

Many strategies have previously been implemented to prevent fetal overgrowth potentially resulting in obstructed labour. Rather than fetal size alone an overall assessment of the relation between the passage (pelvic inlet) and the passenger should be more helpful in predicting labour dystocia linked to cephalo-pelvic disproportion. The aim of this study is to evaluate the performance of the ratio between the sonographic measurement of fetal Head Circumference (HC) to the Obstetric Conjugate (OC) (HC/OC ratio) in the prediction of the mode of delivery.

Serial Measurements of Fetal Head Circumference and Abdominal Circumference to Predict Fetal Growth Restriction in a Sri Lankan Study Population

Serial Measurements of Fetal Head Circumference and Abdominal Circumference to Predict Fetal Growth Restriction in a Sri Lankan Study Population

Sonographic Estimation of the Fetal Head Circumference: Accuracy and Factors Affecting the Error

BackgroundSonographic measurement of fetal head circumference (HC) is an essential parameter for the estimation of fetal weight as well as in cases with abnormal fetal head size. Since there is a lack of data, the present study was to assess the accuracy of ultrasonographic estimation of fetal HC and to identify factors that affect the accuracy of fetal HC estimation.Material and MethodsA prospective cohort observational study was conducted for a year. Sonographic fetal biometry including HC was performed, and fetal HC was measured postnatally. Measures of accuracy and various factors which affect the accuracy are analyzed.ResultsUltrasonographic HC underestimated actual postnatal HC in 87.5% and overestimated actual HC in 12.5%. Sonographic underestimation of HC persisted throughout gestation and became more pronounced as gestational age increased. Error in HC was statistically significant in those with low liquor and anterior placenta and in those who had instrumental delivery. Parity, fetal presentation, and maternal diabetes did not affect the error in ultrasonographic measurement of head circumference. When the HC was beyond 95th centile on ultrasound, the error detected postnatally was significant (− 14 mm vs. − 8 mm), though not statistically significant (p value 0.82). The difference between the sonographic and postnatal HC was also related to the mode of delivery with the highest error seen in those who had instrumental vaginal delivery (p value 0.031).ConclusionThe ultrasound estimation of fetal HC is associated with significant underestimation of the actual HC measured postnatally. The error in measuring fetal HC increased in those with advanced gestational age, low liquor, and anterior location of the placenta and in those who had instrumental vaginal delivery. The measurement error may have important implications in specific clinical scenarios like monitoring pregnancy with fetal growth restriction, suspected fetal head growth abnormalities, and labor outcome.

Differences in Biometric Fetal Weight Estimation Accuracy and Doppler Examination Results in Uncomplicated Term Singleton Pregnancies between Vertex and Breech Presentation.

Doppler examination of the umbilical artery and the fetal middle cerebral artery is evaluated predominantly in pregnancies with fetuses in cephalic presentation and never has been elucidated in breech presentation. Evidence on the accuracy of fetal weight estimation in dependence of the fetal presentation is controversial. Nevertheless, clinical decisions including recommendations for a cesarean section or labor induction based on these examinations are applied to pregnancies with fetuses in breech presentation. The objective of this study was to investigate the influence of the fetal presentation on fetal weight estimation accuracy, umbilical artery and middle cerebral artery resistance indices (RI) in a prospective case control study. Ultrasound examinations in 305 uncomplicated term pregnancies (153 vertex presentations, 152 breech) were investigated. Non-parametric variables were compared using Pearson’s chi2 test and Wilcoxon chi2 test, depending on variable scaling. Fetal weight estimation accuracy was not significantly different between vertex presentation group (VP) (6.97%) and breech presentation group (BP) (7.96%, p = 0.099). Fetal head circumference measurements were significantly larger in BP (350 mm vs. 341 mm in VB, p > 0.0001) while abdominal circumferences were significantly smaller (VP: 338 mm, BP: 331 mm, p = 0.0039) and weight estimation was not significantly different. Umbilical artery RIs were not significantly different between VP (54.5) and BP (55.3, p = 0.354). Fetal middle cerebral artery RIs also showed no significant differences (VP: 71.2, BP: 70.7, p = 0.335). Our study shows that fetal Doppler (RI) and weight estimation ultrasound originally calibrated in cephalic pregnancies are applicable to pregnancies with fetuses in breech presentation.

Associations Between Fetal Growth Trajectories and the Development of Myopia by 20 Years of Age.

PurposeTo evaluate the contribution of genetic and early life environmental factors, as reflected by fetal anthropometric growth trajectories, toward the development of myopia during childhood and adolescence.MethodsThis analysis included 498 singleton Caucasian participants from the Raine Study, a pregnancy cohort study based in Western Australia. Serial fetal biometric measurements of these participants were collected via ultrasound scans performed at 18, 24, 28, 34, and 38 weeks’ gestation. At a 20-year follow-up, the participants underwent a comprehensive ophthalmic examination, including cycloplegic autorefraction and ocular biometry measurements. Using a group-based trajectory modeling approach, we identified groups of participants with similar growth trajectories based on measurements of fetal head circumference (HC), abdominal circumference, femur length (FL), and estimated fetal weight (EFW). Differences between trajectory groups with respect to prevalence of myopia, axial length (AL), and corneal radius of curvature measured at the 20-year follow-up were evaluated via logistic regression and analysis of variance.ResultsPrevalence of myopia was highest among participants with consistently short or consistently long FLs (P = 0.04). There was also a trend toward increased prevalence with larger HC in late gestation, although not at a statistically significant level. Trajectory groups reflecting faster HC, FL, or EFW growth correlated with significantly flatter corneas (P = 0.03, P = 0.04, and P = 0.01, respectively) and a general, but not statistically significant, increase in AL.ConclusionsEnvironmental or genetic factors influencing intrauterine skeletal growth may concurrently affect ocular development, with effects persisting into adulthood.

Intrapartum Ultrasound Measurement of Fetal Head Circumference for Prediction of Prolonged Second Stage of Labor

Background: Fetal head circumference was suggested to play a role in determination of the mode of delivery in nulliparous women. Aim of the work: To determine the capability of intrapartum ultrasound measurement of head circumference to monitor second stage of labor progress in an accurate and objective manner as well as its role as a predictor of successful normal vaginal birth. Patients and Methods:130 females who attended to the labor room and fulfil the inclusion criteria underwent ultrasonographic examination prior to the start of labor, and then followed up until delivery. Every woman was followed up by cervical dilatation, and head station every 4 hours. Woman was transferred to operating room when the cervix is fully dilated and head is engaged to determinate the duration of second stage. Fetal heart sounds were auscultated every 30 minutes and plotted on partogram. Shifting to cesarean section was considered when delivery failed to progress, delayed second stage or fetal bradycardia. Results: By using value of 37.0 for Intrapartum head circumference as a cut-off point, we observed a significant difference between both groups [smaller or larger than 37.0] regarding duration of the 2nd stage of labor [P=0.00] & Mode of delivery [P=0.00]. No statistical difference was observed regarding Maternal morbidity [P=0.374] or Neonatal outcome [P=0.412]. Conclusion: There was significant relation between intrapartum head circumference and length of second stage. Intrapartum fetal head circumference is a useful tool to expect the progress of delivery.

Gestational diabetes and ultrasound-assessed fetal growth in South Asian and White European women: findings from a prospective pregnancy cohort

BackgroundMaternal gestational diabetes (GDM) is an established risk factor for large size at birth, but its influence on intrauterine fetal growth in different ethnic populations is less well understood. Here, we examine the joint associations of GDM and ethnicity with longitudinal fetal growth in South Asian and White European origin women.MethodsThis study included 10,705 singletons (4747 White European and 5958 South Asian) from a prospective cohort of women attending an antenatal clinic in Bradford, in the North of England. All women completed a 75-g oral glucose tolerance test at 26–28 weeks’ gestation. Ultrasound measurements of fetal head circumference (HC), femur length (FL) abdominal circumference (AC), and estimated fetal weight (EFW), and corresponding anthropometric measurements at birth were used to derive fetal growth trajectories. Associations of GDM and ethnicity with these trajectories were assessed using multilevel fractional polynomial models.ResultsEight hundred thirty-two pregnancies (7.8%) were affected by GDM: 10.4% of South Asians and 4.4% of White Europeans. GDM was associated with a smaller fetal size in early pregnancy [differences (95% CI) in mean HC at 12 weeks and mean AC and EFW at 16 weeks comparing fetuses exposed to GDM to fetuses unexposed (reference) = − 1.8 mm (− 2.6; − 1.0), − 1.7 mm (− 2.5; − 0.9), and − 6 g (− 10; − 2)] and a greater fetal size from 24 weeks’ gestation through to term [differences (95% CI) in mean HC, AC, and EFW comparing fetuses exposed to GDM to those unexposed = 0.9 mm (0.3; 1.4), 0.9 mm (0.2; 1.7), and 7 g (0; 13) at 24 weeks]. Associations of GDM with fetal growth were of similar magnitude in both ethnic groups. Growth trajectories, however, differed by ethnicity with South Asians being smaller than White Europeans irrespective of GDM status. Consequently, South Asian fetuses exposed to GDM were smaller across gestation than fetuses of White Europeans without GDM.ConclusionsIn both ethnic groups, GDM is associated with early fetal size deviations prior to GDM diagnosis, highlighting the need for novel strategies to diagnose pregnancy hyperglycemia earlier than current methods. Our findings also suggest that ethnic-specific fetal growth criteria are important in identifying hyperglycemia-associated pathological effects.

Automated measurement of fetal head circumference using 2D ultrasound images.

In this paper we present a computer aided detection (CAD) system for automated measurement of the fetal head circumference (HC) in 2D ultrasound images for all trimesters of the pregnancy. The HC can be used to estimate the gestational age and monitor growth of the fetus. Automated HC assessment could be valuable in developing countries, where there is a severe shortage of trained sonographers. The CAD system consists of two steps: First, Haar-like features were computed from the ultrasound images to train a random forest classifier to locate the fetal skull. Secondly, the HC was extracted using Hough transform, dynamic programming and an ellipse fit. The CAD system was trained on 999 images and validated on an independent test set of 335 images from all trimesters. The test set was manually annotated by an experienced sonographer and a medical researcher. The reference gestational age (GA) was estimated using the crown-rump length measurement (CRL). The mean difference between the reference GA and the GA estimated by the experienced sonographer was 0.8 ± 2.6, −0.0 ± 4.6 and 1.9 ± 11.0 days for the first, second and third trimester, respectively. The mean difference between the reference GA and the GA estimated by the medical researcher was 1.6 ± 2.7, 2.0 ± 4.8 and 3.9 ± 13.7 days. The mean difference between the reference GA and the GA estimated by the CAD system was 0.6 ± 4.3, 0.4 ± 4.7 and 2.5 ± 12.4 days. The results show that the CAD system performs comparable to an experienced sonographer. The presented system shows similar or superior results compared to systems published in literature. This is the first automated system for HC assessment evaluated on a large test set which contained data of all trimesters of the pregnancy.

Human-level Performance On Automatic Head Biometrics In Fetal Ultrasound Using Fully Convolutional Neural Networks.

Measurement of head biometrics from fetal ultrasonography images is of key importance in monitoring the healthy development of fetuses. However, the accurate measurement of relevant anatomical structures is subject to large inter-observer variability in the clinic. To address this issue, an automated method utilizing Fully Convolutional Networks (FCN) is proposed to determine measurements of fetal head circumference (HC) and biparietal diameter (BPD). An FCN was trained on approximately 2000 2D ultrasound images of the head with annotations provided by 45 different sonographers during routine screening examinations to perform semantic segmentation of the head. An ellipse is fitted to the resulting segmentation contours to mimic the annotation typically produced by a sonographer. The model's performance was compared with inter-observer variability, where two experts manually annotated 100 test images. Mean absolute model-expert error was slightly better than inter-observer error for HC (1.99mm vs 2.16mm), and comparable for BPD (0.61mm vs 0.59mm), as well as Dice coefficient (0.980 vs 0.980). Our results demonstrate that the model performs at a level similar to a human expert, and learns to produce accurate predictions from a large dataset annotated by many sonographers. Additionally, measurements are generated in near real-time at 15fps on a GPU, which could speed up clinical workflow for both skilled and trainee sonographers.

Ultrasonographic estimation of fetal weight: development of new model and assessment of performance of previous models.

To develop a new formula for ultrasonographic estimation of fetal weight and evaluate the accuracy of this and all previous formulae in the prediction of birth weight. The study population consisted of 5163 singleton pregnancies with fetal biometry at 22-43 weeks' gestation and live birth of a phenotypically normal neonate within 2 days of the ultrasound examination. Multivariable fractional polynomial analysis was used to determine the combination of variables that provided the best-fitting models for estimated fetal weight (EFW). A systematic review was also carried out of articles reporting formulae for EFW and comparing EFW to actual birth weight. The accuracy of each model for EFW was assessed by comparing mean percentage error, absolute mean error (AE), proportion of pregnancies with AE ≤ 10% and Euclidean distance. The most accurate models, with the lowest Euclidean distance and highest proportion of AE ≤ 10%, were provided by the formulae incorporating ≥ 3 rather than < 3 biometrical measurements. The systematic review identified 45 studies describing a total of 70 models for EFW by various combinations of measurements of fetal head circumference (HC), biparietal diameter, femur length (FL) and abdominal circumference (AC). The most accurate model with the lowest Euclidean distance and highest proportion of AE ≤ 10% was provided by the formula of Hadlock et al., published in 1985, which incorporated measurements of HC, AC and FL; there was a highly significant linear association between EFW and birth weight (r= 0.959; P< 0.0001), and EFW was within 10% of birth weight in 80% of cases. The performance of the best model developed in this study, utilizing HC, AC and FL, was very similar to that of Hadlock et al. CONCLUSION: Despite many efforts to develop new models for EFW, the one reported in 1985 by Hadlock et al., from measurements of HC, AC and FL, provides the most accurate prediction of birth weight and can be used for assessment of all babies, including those suspected to be either small or large. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Fetal Medicine Foundation fetal and neonatal population weight charts.

To develop fetal and neonatal population weight charts. The rationale was that, while reference ranges of estimated fetal weight (EFW) are representative of the whole population, the traditional approach of deriving birth-weight (BW) charts is misleading, because a large proportion of babies born preterm arise from pathological pregnancy. We propose that the reference population for BW charts, as in the case of EFW charts, should comprise all babies at a given gestational age, including those still in utero. Two sources of data were used for this study. For both, the inclusion criteria were singleton pregnancy, dating by fetal crown-rump length at 11 + 0 to 13 + 6 weeks' gestation, availability of ultrasonographic measurements of fetal head circumference (HC), abdominal circumference (AC) and femur length (FL) and live birth of phenotypically normal neonate. Dataset 1 comprised a sample of 5163 paired measurements of EFW and BW; ultrasound examinations were carried out at 22-43 weeks' gestation and birth occurred within 2 days of the ultrasound examination. EFW was derived from the HC, AC and FL measurements using the formula reported by Hadlock et al. in 1985. Dataset 2 comprised a sample of 95 579 pregnancies with EFW obtained by routine ultrasonographic fetal biometry at 20 + 0 to 23 + 6 weeks' gestation (n= 45 034), 31 + 0 to 33 + 6 weeks (n= 19 224) or 35 + 0 to 36 + 6 weeks (n= 31 321); for the purpose of this study we included data for only one of the three visits per pregnancy. In the development of reference ranges of EFW and BW according to gestational age, the following assumptions were made: first, that EFW and BW have a common median, dependent on gestational age; and second, that deviations from the median occur in both EFW and BW and these deviations are correlated with different levels of spread for EFW and BW, dependent on gestational age. We adopted a Bayesian approach to inference, combining information from the two datasets using Markov Chain Monte-Carlo sampling. The fitted model assumed that the mean log transformed measurements of EFW and BW are related to gestational age according to a cubic equation and that deviations about the mean follow a bivariate Gaussian distribution. In the case of EFW in Dataset 2, there was a good distribution of values < 3rd , < 5th , < 10th , > 90th , > 95th and > 97th percentiles of the reference range of EFW according to gestational age throughout the gestational age range of 20 + 0 to 36 + 6weeks. In the case of BW, there was a good distribution of values only for the cases delivered > 39 weeks' gestation. For preterm births, particularly at 27-36 weeks, BW was below the 3rd , 5th and 10th percentiles in a very high proportion of cases, particularly in cases of iatrogenic birth. The incidence of small-for-gestational-age fetuses and neonates in the respective EFW and BW charts was higher in women of black than those of white racial origin. We established a BW chart for all babies at a given gestational age, including those still in utero, thereby overcoming the problem of underestimation of growth restriction in preterm birth. BW and EFW charts have a common median but differ in the levels of spread from the median. Copyright © 2018 ISUOG. Published by John Wiley & Sons Ltd.

Gestational Age Estimation by Ultrasonographic Measurements of Fetal Head Circumference in Local Population, Karnataka, India

Gestational Age Estimation by Ultrasonographic Measurements of Fetal Head Circumference in Local Population, Karnataka, India

Clinical assessment and brain findings in a cohort of mothers, fetuses and infants infected with ZIKA virus

Congenital Zika virus (ZIKV) infection can be detected in both the presence and absence of microcephaly and manifests as a number of signs and symptoms that are detected clinically and by neuroimaging. However, to date, qualitative and quantitative measures for the purpose of diagnosis and prognosis are limited. Main objectives of this study conducted on fetuses and infants with confirmed congenital Zika virus infection and detected brain abnormalities were (1) to assess the prevalence of microcephaly and the frequency of the anomalies that include a detailed description based on ultrasound and magnetic resonance imaging in fetuses and ultrasound, magnetic resonance imaging, and computed tomography imaging postnatally, (2) to provide quantitative measures of fetal and infant brain findings by magnetic resonance imaging with the use of volumetric analyses and diffusion-weighted imaging, and (3) to obtain additional information from placental and fetal histopathologic assessments and postnatal clinical evaluations. This is a longitudinal cohort study of Zika virus-infected pregnancies from a single institution in Colombia. Clinical and imaging findings of patients with laboratory-confirmed Zika virus infection and fetal brain anomalies were the focus of this study. Patients underwent monthly fetal ultrasound scans, neurosonography, and a fetal magnetic resonance imaging. Postnatally, infant brain assessment was offered by the use of ultrasound imaging, magnetic resonance imaging, and/or computed tomography. Fetal head circumference measurements were compared with different reference ranges with <2 or <3 standard deviations below the mean for the diagnosis of microcephaly. Fetal and infant magnetic resonance imaging images were processed to obtain a quantitative brain volumetric assessment. Diffusion weighted imaging sequences were processed to assess brain microstructure. Anthropometric, neurologic, auditory, and visual assessments were performed postnatally. Histopathologic assessment was included if patients opted for pregnancy termination. All women (n=214) had been referred for Zika virus symptoms during pregnancy that affected themselves or their partners or if fetal anomalies that are compatible with congenital Zika virus syndrome were detected. A total of 12 pregnant patients with laboratory confirmation of Zika virus infection were diagnosed with fetal brain malformations. Most common findings that were assessed by prenatal and postnatal imaging were brain volume loss (92%), calcifications (92%), callosal anomalies (100%), cortical malformations (89%), and ventriculomegaly (92%). Results from fetal brain volumetric assessment by magnetic resonance imaging showed that 1 of the most common findings associated with microcephaly was reduced supratentorial brain parenchyma and increased subarachnoid cerebrospinal fluid. Diffusion weighted imaging analyses of apparent diffusion coefficient values showed microstructural changes. Microcephaly was present in 33.3-58.3% of the cases at referral and was present at delivery in 55.6-77.8% of cases. At birth, most of the affected neonates (55.6-77.8%) had head circumference measurements >3 standard deviations below the mean. Postnatal imaging studies confirmed brain malformations that were detected prenatally. Auditory screening results were normal in 2 cases that were assessed. Visual screening showed different anomalies in 2 of the 3 cases that were examined. Pathologic results that were obtained from 2 of the 3 cases who opted for termination showed similar signs of abnormalities in the central nervous system and placental analyses, including brain microcalcifications. Congenital microcephaly is not an optimal screening method for congenital Zika virus syndrome, because it may not accompany other evident and preceding brain findings; microcephaly could be an endpoint of the disease that results from progressive changes that are related to brain volume loss. Long-term studies are needed to understand the clinical and developmental relevance of these findings.

Role of Ultrasonographic Measurement of Fetal Head Circumference in the Evaluation of Gestational age in Bangladeshi Women

Determination of gestational age by ultrasound has now become an integral part of maternal antenatal care. Accurate assessment of gestational age by sonography is now essential for obstetric management particularly due to term, preterm and post date management. Timing of elective caesarean delivery and decision whether to consider a fetus at risk for intrauterine growth retardation depends in part on the estimated age. In this study gestational age was determined on the basis of head circumference (HC) and correlation was established between weeks of gestation calculated from LMP. A cross sectional study was carried out in the department of Radiology &amp; Imaging, Mymensingh Medical College Hospital during the period of January 2011 to June 2012. Three hundred ninety seven normal pregnant Bangladeshi women age range from 20 to 36 years with apparently healthy fetuses between 18 to 38 weeks of gestation referred for ultrasonic evaluation of pregnancy profile. Mean age was 29.60 years with standard deviation (SD) +0.67. Aim of this study was to determine relationship between menstrual age and HC. Result of this study may give idea about gestational age calculated by LMP of 397 cases and expressed in weeks. Estimated gestational age was determined by HC evaluated by US and expressed in weeks. Significant positive correlation was found between gestational age measured by HC and LMP. Estimated gestational age measured by HC had very close relation with weeks of gestation(LMP), which is 2 to 3 days less from weeks of gestation (LMP) during 18-38 weeks of gestation variation was only 2 to 4 days less from weeks of gestation (LMP). A strong positive significant correlation (r=0.987, P&lt;0.001) was found between weeks of gestation and predicted gestational age measured from HC. Significant relationship between gestational age measured by LMP with estimated gestational age evaluated by head circumference.&#x0D; CBMJ 2017 July: Vol. 06 No. 02 P: 06-11

International estimated fetal weight standards of the INTERGROWTH-21st Project.

ABSTRACTObjectiveEstimated fetal weight (EFW) and fetal biometry are complementary measures used to screen for fetal growth disturbances. Our aim was to provide international EFW standards to complement the INTERGROWTH‐21st Fetal Growth Standards that are available for use worldwide.MethodsWomen with an accurate gestational‐age assessment, who were enrolled in the prospective, international, multicenter, population‐based Fetal Growth Longitudinal Study (FGLS) and INTERBIO‐21st Fetal Study (FS), two components of the INTERGROWTH‐21st Project, had ultrasound scans every 5 weeks from 9–14 weeks' until 40 weeks' gestation. At each visit, measurements of fetal head circumference (HC), biparietal diameter, occipitofrontal diameter, abdominal circumference (AC) and femur length (FL) were obtained blindly by dedicated research sonographers using standardized methods and identical ultrasound machines. Birth weight was measured within 12 h of delivery by dedicated research anthropometrists using standardized methods and identical electronic scales. Live babies without any congenital abnormality, who were born within 14 days of the last ultrasound scan, were selected for inclusion. As most births occurred at around 40 weeks' gestation, we constructed a bootstrap model selection and estimation procedure based on resampling of the complete dataset under an approximately uniform distribution of birth weight, thus enriching the sample size at extremes of fetal sizes, to achieve consistent estimates across the full range of fetal weight. We constructed reference centiles using second‐degree fractional polynomial models.ResultsOf the overall population, 2404 babies were born within 14 days of the last ultrasound scan. Mean time between the last scan and birth was 7.7 (range, 0–14) days and was uniformly distributed. Birth weight was best estimated as a function of AC and HC (without FL) as log(EFW) = 5.084820 − 54.06633 × (AC/100)3 − 95.80076 × (AC/100)3 × log(AC/100) + 3.136370 × (HC/100), where EFW is in g and AC and HC are in cm. All other measures, gestational age, symphysis–fundus height, amniotic fluid indices and interactions between biometric measures and gestational age, were not retained in the selection process because they did not improve the prediction of EFW. Applying the formula to FGLS biometric data (n = 4231) enabled gestational age‐specific EFW tables to be constructed. At term, the EFW centiles matched those of the INTERGROWTH‐21st Newborn Size Standards but, at < 37 weeks' gestation, the EFW centiles were, as expected, higher than those of babies born preterm. Comparing EFW cross‐sectional values with the INTERGROWTH‐21st Preterm Postnatal Growth Standards confirmed that preterm postnatal growth is a different biological process from intrauterine growth.ConclusionsWe provide an assessment of EFW, as an adjunct to routine ultrasound biometry, from 22 to 40 weeks' gestation. However, we strongly encourage clinicians to evaluate fetal growth using separate biometric measures such as HC and AC, as well as EFW, to avoid the minimalist approach of focusing on a single value. © 2016 Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Intrapartum fetal head circumference and estimated fetal weight as predictors of operative delivery.

To assess intrapartum sonographic measurements of fetal head circumference (HC) and estimated fetal weight (EFW) to predict operative delivery. In a prospective study, 200 spontaneously parturient primiparous women aged 20-30years were enrolled at a teaching hospital in Cairo, Egypt, between October 2, 2015, and January 28, 2016. HC and EFW were measured by transabdominal ultrasonography. After delivery, the association between type of delivery and ultrasonography findings was assessed. Intrapartum HC and EFW were significantly higher among women with operative delivery (n=76) than among those with normal vaginal delivery (n=124; P<0.001 for both). Intrapartum HC of 36.8cm or more was associated with an increased risk of operative delivery (relative risk [RR] 2.87, 95% CI 1.87-4.41), as was EFW of 3920g or more (RR 3.69, 95% CI 2.13-6.40). The area under the receiver operating characteristic curve was 0.807 and 0.748 for HC and EFW, respectively (P<0.001 for both). At 36.8-cm cutoff, HC had 44.7% sensitivity, 91.9% specificity, 77.3% positive predictive value (PPV), and 73.1% negative predictive value (NPV). At 3920-g cutoff, EFW had 68.4% sensitivity, 82.3% specificity, 70.3% PPV, and 81.0% NPV. Intrapartum HC and EFW were directly correlated with second-stage duration (P=0.005 and 0.002, respectively). Intrapartum HC and EFW seem to be good predictors of operative delivery.

Scientific basis for standardization of fetal head measurements by ultrasound: a reproducibility study.

ABSTRACTObjectiveTo compare the standard methods for ultrasound measurement of fetal head circumference (HC) and biparietal diameter (BPD) (outer‐to‐outer (BPDoo) vs outer‐to‐inner (BPDoi) caliper placement), and compare acquisition of these measurements in transthalamic (TT) vs transventricular (TV) planes.MethodsThis study utilized ultrasound images acquired from women participating in the Oxford arm of the INTERGROWTH‐21st Project. In the first phase of the study, BPDoo and BPDoi were measured on stored images. In the second phase, real‐time measurements of BPD, occipitofrontal diameter (OFD) and HC in TT and TV planes were obtained by pairs of sonographers. Reproducibility of measurements made by the same (intraobserver) and by different (interobserver) sonographers, as well as the reproducibility of caliper placement and measurements obtained in different planes, was assessed using Bland–Altman plots.ResultsIn Phase I, we analyzed ultrasound images of 108 singleton fetuses. The mean intraobserver and interobserver differences were < 2% (1.34 mm) and the 95% limits of agreement were < 5% (3 mm) for both BPDoo and BPDoi. Neither method for measuring BPD showed consistently better reproducibility. In Phase II, we analyzed ultrasound images of 100 different singleton fetuses. The mean intraobserver and interobserver differences were < 1% (2.26 mm) and the 95% limits of agreement were < 8% (14.45 mm) for all fetal head measurements obtained in TV and TT planes. Neither plane for measuring fetal head showed consistently better reproducibility. Measurement of HC using the ellipse facility was as reproducible as HC calculated from BPD and OFD. OFD by itself was the least reproducible of all fetal head measurements.ConclusionsMeasurements of BPDoi and BPDoo are equally reproducible; however, we believe BPDoo should be used in clinical practice as it allows fetal HC to be measured and compared with neonatal HC. For all head measurements, TV and TT planes provide equally reproducible values at any gestational age, and HC values are similar in both planes. Fetal head measurement in the TT plane is preferable as international standards in this plane are available; however, measurements in the TV plane can be plotted on the same standards. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.