Estimation Of Gestational Age Research Articles

Correcting for measurement error in assessing gestational age in a low-resource setting: a regression calibration approach.

Measurement error in gestational age (GA) may bias the association of GA with a health outcome. Ultrasound-based GA is considered the gold standard and is not readily available in low-resource settings. We corrected for measurement error in GA based on fundal height (FH) and date of last menstrual period (LMP) using ultrasound from the sub-cohort and adjusted for the bias in associating GA with neonatal mortality and low birth weight (< 2,500 grams, LBW). We used data collected from 01/2015 to 09/2019 from pregnant women enrolled at two public hospitals in Siaya county, Kenya (N = 2,750). We used regression calibration to correct for measurement error in FH- and LMP-based GA accounting for maternal and child characteristics. We applied logistic regression to associate GA with neonatal mortality and low birth weight, with and without calibrating FH- and LMP-based GA. Calibration improved the precision of LMP (correlation coefficient, from 0.48 to 0.57) and FH-based GA ( from 0.82 to 0.83). Calibrating FH/LMP-based GA eliminated the bias in the mean GA estimates. The log odds ratio that quantifies the association of GA with neonatal mortality increased by 29% (from -0.159 to -0.205) by calibrating FH-based GA and by more than twofold (from -0.158 to -0.471) by calibrating LMP-based GA. Calibrating FH/LMP-based GA improved the accuracy and precision of GA estimates and strengthened the association of GA with neonatal mortality/LBW. When assessing GA, neonatal public health and clinical interventions may benefit from calibration modeling in settings where ultrasound may not be fully available.

National, regional, and global estimates of preterm birth in 2020, with trends from 2010: a systematic analysis

Preterm birth is the leading cause of neonatal mortality and is associated with long-term physical, neurodevelopmental, and socioeconomic effects. This study updated national preterm birth rates and trends, plus novel estimates by gestational age subgroups, to inform progress towards global health goals and targets, and aimed to update country, regional, and global estimates of preterm birth for 2020 in addition to trends between 2010 and 2020. We systematically searched population-based, nationally representative data on preterm birth from Jan 1, 2010, to Dec 31, 2020 and study data (26 March-14 April, 2021) for countries and areas with no national-level data. The analysis included 679 data points (86% nationally representative administrative data [582 of 679 data points]) from 103 countries and areas (62% of countries and areas having nationally representative administrative data [64 of 103 data points]). A Bayesian hierarchical regression was used for estimating country-level preterm rates, which incoporated country-specific intercepts, low birthweight as a covariate, non-linear time trends, and bias adjustments based on a data quality categorisation, and other indicators such as method of gestational age estimation. An estimated 13·4 million (95% credible interval [CrI] 12·3-15·2 million) newborn babies were born preterm (<37 weeks) in 2020 (9·9% of all births [95% CrI 9·1-11·2]) compared with 13·8 million (12·7-15·5 million) in 2010 (9·8% of all births [9·0-11·0]) worldwide. The global annual rate of reduction was estimated at -0·14% from 2010 to 2020. In total, 55·6% of total livebirths are in southern Asia (26·8% [36 099 000 of 134 767 000]) and sub-Saharan Africa (28·7% [38 819 300 of 134 767 000]), yet these two regions accounted for approximately 65% (8 692 000 of 13 376 200) of all preterm births globally in 2020. Of the 33 countries and areas in the highest data quality category, none were in southern Asia or sub-Saharan Africa compared with 94% (30 of 32 countries) in high-income countries and areas. Worldwide from 2010 to 2020, approximately 15% of all preterm births occurred at less than 32 weeks of gestation, requiring more neonatal care (<28 weeks: 4·2%, 95% CI 3·1-5·0, 567 800 [410 200-663 200 newborn babies]); 28-32 weeks: 10·4% [9·5-10·6], 1 392 500 [1 274 800-1 422 600 newborn babies]). There has been no measurable change in preterm birth rates over the last decade at global level. Despite increasing facility birth rates and substantial focus on routine health data systems, there remain many missed opportunities to improve preterm birth data. Gaps in national routine data for preterm birth are most marked in regions of southern Asia and sub-Saharan Africa, which also have the highest estimated burden of preterm births. Countries need to prioritise programmatic investments to prevent preterm birth and to ensure evidence-based quality care when preterm birth occurs. Investments in improving data quality are crucial so that preterm birth data can be improved and used for action and accountability processes. The Children's Investment Fund Foundation and the UNDP, United Nations Population Fund-UNICEF-WHO-World Bank Special Programme of Research, Development and Research Training in Human Reproduction.

Postconceptual Neonatal Dating by Transmastoid Ultrasound of Transcerebellar Diameter-Comparison to Crown Rump Length Measurement: A Proof of Concept Paper.

Transcerebellar diameter (TCD) has been utilized prenatally as a tool to estimate gestational age (GA) when fetal growth aberrations are suspected. Traditionally, first trimester ultrasound (1TUS) has been the gold standard of dating a pregnancy in spontaneous pregnancies. We sought to determine if neonatal TCD measurement was as accurate as 1TUS in the estimation of postconceptual gestational age (PCGA). A retrospective cohort from a registry of high-quality transmastoid views of consecutive patients from July 2019 to November 2020, delivered from 24 to 34 weeks GA, and with a 1TUS were included. The reference PCGA was the sum of the GA at delivery by 1TUS and day of life. The PCGA by TCD was calculated from Chang et al for GA by TCD. Reference and experimental values were compared by correlation, agreement within 7 days, and Bland-Altman analysis. Of the 154 individual patients in the registry of high-quality transmastoid views during the study period, 62 met inclusion and exclusion criteria. PCGA by 1TUS and TCD were highly correlated (r = 0.86, P < .001; κ = 47% agreement within 7 days of PCGA). The bias of PCGA by TCD was 4.6 days earlier than the PCGA by 1TUS (95% confidence interval of agreement: -29.2, 20). PCGA estimation by neonatal transmastoid TCD was highly correlated with that of 1TUS. It generally underestimates GA by 4.6 days. This relationship warrants further investigation to determine if this method of estimating PCGA in undated gestations is generalizable.

Postnatal foot length in the estimation of gestational age in relation to intrauterine growth pattern among Nigerian neonates.

To determine the relationship between postnatal foot lengths and estimated gestational age (EGA) in relation to intrauterine growth patterns determined at birth among Nigerian neonates. Hospital-based, cross-sectional. Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria. 260 neonates with EGA 30- 42 weeks within 48 hours of life. Postnatal foot lengths (FL) were measured with Vernier digital calliper in millimetres. The intra-uterine growth pattern was determined using the Lubchenco chart. Pearson correlation and regression analysis tests were performed. Postnatal foot length in relation to Intra-Uterine Growth Pattern. The mean postnatal FL had a strong positive correlation with the EGA from 30 through 42 weeks (r = 0.855, p < 0.001). The overall mean foot length for preterm neonates was 65.44 (6.92) mm, while that of term neonates was 77.92 (4.24) mm. The linear regression equation was generated as: EGA = 9.43 + (0.37 × FL), p < 0.001. The EGA as measured by FL had the highest positive correlation with Small for Gestational Age (SGA) intra-uterine-growth pattern, followed by Appropriate for Gestational Age (AGA) and least by Large for Gestational Age (LGA) respectively (r = 0.936> 0.861 > 0.666). The postnatal foot length correlated well with estimated gestational age, and the correlation was best among SGA infants. None declared.

Evaluating Fetal Kidney Length and Trans-cerebellar Diameter as Ultrasound Biometry Parameters for Gestational Age Estimation in the Third Trimester

Evaluating Fetal Kidney Length and Trans-cerebellar Diameter as Ultrasound Biometry Parameters for Gestational Age Estimation in the Third Trimester

Can the date of last menstrual period be trusted in the first trimester? Comparisons of gestational age measures from a prospective cohort study in six low-income to middle-income countries

ObjectivesWe examined gestational age (GA) estimates for live and still births, and prematurity rates based on last menstrual period (LMP) compared with ultrasonography (USG) among pregnant women at seven sites...

Validation of Ultrasound Dating Protocols Using Data From Twins Conceived Through In Vitro Fertilization in Nova Scotia: A Retrospective Cohort Study

ObjectivesClinical practice guidelines recommend determining gestational age (GA) for twin pregnancies using the fetal crown rump length (CRL) of the larger fetus. This study investigated whether the CRL of the larger or smaller fetus at 11–14 weeks best predicted in vitro fertilization (IVF) assigned GA. MethodsA retrospective cohort study of twin pregnancies conceived by IVF ± intracytoplasmic sperm injection, 2004–2022, generated GA estimations for each co-twin CRL at the 11–14 week ultrasound, to determine which fetus (smaller or larger) more consistently predicted IVF-assigned GA. Monoamniotic twins and twins with known structural or vascular abnormalities were excluded. Paired t tests evaluated the ability of CRL to predict GA, and logistic regression evaluated the predictive ability of each of the co-twin groups with increasing size differences. Statistical significance was set at P < 0.05. ResultsViewpoint 6 identified 359 eligible twin pairs. CRL was closest with the smaller fetus (0.38 days); CRL for both the smaller (95% CI 0.16–0.61) and the larger (2.25 days, 95% CI 2.04–2.46) fetus showed deviation from IVF-assigned GA. As the absolute difference between the small and large fetus increased, the ultrasound-estimated GA of the smaller fetus was still consistently closer to IVF-assigned GA. ConclusionsIn this selected population of twins with known GA, the CRL of the smaller fetus more accurately predicted IVF-assigned GA even with increasing differences in fetal size. These findings provide important information for appropriately dating pregnancies to facilitate adherence to national guidelines to monitor for pregnancy complications, and plan frequency and type of fetal surveillance, as well as timing of delivery.

Using Cognitive Task Analysis to Develop a Protocol for Teaching Ultrasound Pregnancy Diagnosis in the Bitch to Undergraduate Veterinary Students

Pregnancy diagnosis in the bitch is routinely performed using ultrasound and is therefore an important skill for veterinarians to have been exposed to during undergraduate training. Proficiency of this skill is difficult to achieve, due to limited exposure to suitable live patients, and animal welfare considerations limiting repeated performance on the same bitch. Models have been beneficial in allowing undergraduates to perform a range of ultrasound techniques without the use of live animals. Using clinical veterinarians and a model created at the University of Surrey, cognitive task analysis (CTA) was used to construct a list of instructional steps required to perform ultrasound pregnancy diagnosis. Experts were asked to evaluate the existing model then video recorded while demonstrating the skill on the model as if teaching a novice student. Anonymized and muted video footage along with transcribed audio files were used to create a draft teaching protocol. A group consensus for the final teaching protocol was developed following a semi-structured interview. The final teaching protocol had 23 steps to guide a novice to perform this skill, broken down into three stages; set-up and preparation, pregnancy identification, and estimation of gestational age. Not all steps were both performed and verbalized by all of the experts, hence the need for a panel discussion to confirm a final teaching protocol. This study demonstrated that CTA is useful in compiling a comprehensive list of steps, for a teaching protocol, including those which may have been missed if demonstrated through a lone subject matter expert.

Role of Foetal Trans-cerebellar Diameter in the Prediction of Gestational Age in Correlation with other Foetal Biometric Parameter: A Cross-sectional Study in a Secondary Hospital of Bangladesh

Introduction: Uncertain gestational age is associated with higher perinatal mortality rates. Accurate assessment of gestational age is an important parameter in obstetrics for the management of pregnancy and evaluation of foetal development. Objective: To evaluate whether trans-cerebellar diameter (TCD) in singleton uncomplicated gestations can serve as a reliable predictor of gestational age (GA) in fetuses between 18-38 weeks of pregnancy. Methods: This cross-sectional study was carried out in the department of Radiology and Imaging of CMH, Ghatail, from January 2019 to December 2019 among purposively selected 89 outpatient and admitted pregnant women without any complication having regular menstrual cycle and confirmed about last menstrual period (LMP). The transabdominal USG was performed in each patient and trans-cerebellar diameter was taken which was later correlated with other foetal biometric parameters like biparietaldiameter (BPD), femoral length (FL) etc. Results: Most of the patients belonged to 21-25 years age group (32.6%). Mean age of the study subjects was 26.94±5.70 years ranging from 19 to 38 years and were predominantly (51.7%) primipara. Mean gestational age was 220.69±37.30 days by LMP, 216.20±36.06 days by BPD, 219.00±38.43 days by FL and 218.81±39.36 days by TCD. Mean of biparietal diameter, femoral length and transverse cerebellar diameter were 7.59±1.40cm, 5.91± 1.33cm and 3.93±1.00cm respectively. A significant positive linear correlation between GA by LMP with GA by BPD, FL and TCD was observed (p&lt;0.001). Conclusion: Foetal trans-cerebellar diameter is a reliable sonological parameter for the estimation of foetal gestational age and dating of pregnancy can be made depending on TCD in the pregnant women with unsure of their LMP. JAFMC Bangladesh. Vol 18, No 2 (December) 2022: 40-45

Ultrasound Measurement of Fetal Kidney Length in Normal Pregnancy and its Correlation with Gestational Age.

To establish a nomogram of fetal kidney length for a normal pregnancy from 20 to 41 weeks of gestational age. A prospective cross-sectional study was carried out in the Department of radio-diagnosis and imaging BPKIHS, Dharan. 400 kidneys of 200 fetuses between the gestational age 20 to 41 weeks were scanned. Renal measurement was performed by ultrasonography. Analysis was performed on data obtained from 200 normal fetuses. Size charts for right, left and mean fetal kidney length with standard deviation were presented for each weeks of gestation from 20 weeks to 41 weeks. The difference in renal length between right and left side was statistically not significant.There was significant correlation between gestational age and fetal kidney length (r=0.947, p=0.001). Fetal kidney length can be used as an adjunct parameter for estimation of gestation age.

Who is pregnant? Defining real-world data-based pregnancy episodes in the National COVID Cohort Collaborative (N3C).

To define pregnancy episodes and estimate gestational age within electronic health record (EHR) data from the National COVID Cohort Collaborative (N3C). We developed a comprehensive approach, named Hierarchy and rule-based pregnancy episode Inference integrated with Pregnancy Progression Signatures (HIPPS), and applied it to EHR data in the N3C (January 1, 2018-April 7, 2022). HIPPS combines: (1) an extension of a previously published pregnancy episode algorithm, (2) a novel algorithm to detect gestational age-specific signatures of a progressing pregnancy for further episode support, and (3) pregnancy start date inference. Clinicians performed validation of HIPPS on a subset of episodes. We then generated pregnancy cohorts based on gestational age precision and pregnancy outcomes for assessment of accuracy and comparison of COVID-19 and other characteristics. We identified 628 165 pregnant persons with 816 471 pregnancy episodes, of which 52.3% were live births, 24.4% were other outcomes (stillbirth, ectopic pregnancy, abortions), and 23.3% had unknown outcomes. Clinician validation agreed 98.8% with HIPPS-identified episodes. We were able to estimate start dates within 1 week of precision for 475 433 (58.2%) episodes. 62 540 (7.7%) episodes had incident COVID-19 during pregnancy. HIPPS provides measures of support for pregnancy-related variables such as gestational age and pregnancy outcomes based on N3C data. Gestational age precision allows researchers to find time to events with reasonable confidence. We have developed a novel and robust approach for inferring pregnancy episodes and gestational age that addresses data inconsistency and missingness in EHR data.

Ultrasonographic Estimation of the Gestational Age Using the Fetal Kidney Length in the Second and Third Trimesters of Pregnancy Among South Indian Antenatal Women: A Cross-Sectional Study.

Background and Objective Accurately estimating the age of the fetus is crucial to prevent morbidity and mortality for both the fetus and mother during the perinatal period. Additionally, it enables early intervention in cases of complicated pregnancies. Multiple parameters are used for the estimation of fetal gestational age (FGA) and the expected date of delivery (EDD), butno single parameter is found to be accurate and standard. This study aims to analyze the fetal kidney length (FKL) as a means to estimate gestational age and investigate the growth pattern of the fetal kidney during the early and late weeks of gestation. Furthermore, it seeks to establish correlations between FKL and gold standard parameters from the 18th week to the 38th week of gestation. Methodology This cross-sectional research was carried out after obtaining proper institutional ethical clearance. The pregnant women who came to the gynecology outpatient department (OPD) between 18 and 38 weeks were included in this study after obtaining informed consent. The fetal biometry was measured using the ultrasonographic transducer (3-5 MHz). Results The mean FKL exhibited a consistent increase throughout the entire pregnancy, ranging from 16.50 ± 2.10to 39.20 ± 3.10 mm. The rate of increase in FKL was significant between the early weeks (18-24) of pregnancy, with insignificant growth in other weeks of gestation. The growth of the fetal kidney (length) exhibited a gradual increase from the early weeks to the late weeks of pregnancy, with a consistent growth rate of approximately 1mm per week from 18 to 35 weeks. However, in the final three weeks of pregnancy (36th, 37th, and 38th weeks), the FKL measurements were recorded as 37.90 ± 3.90, 38.90 ± 3.10, and 40.20 ± 3.10 mm, respectively. A positive correlationwas noted between the FKL with all standard parameters such as biparietal diameter (BPD), femur length (FL), head circumference (HC), and abdominal circumference (AC). Conclusions This study concluded that incorporating FKLalongside standard fetal biometric parameters such as BPD, FL, HC, and ACenhanced the accuracy of calculating FGAand EDDduring the early second trimester. Furthermore, it proved beneficial in diagnosing fetal anomalies during early pregnancies.

ULTRASOUND FETAL KIDNEY LENGTH FOR ASSESSMENT OF GESTATIONAL AGE

Fetal kidney length (FKL) has recently been found to have a strong correlation with gestational age. According to the findings of these investigations, the fetal kidney length may be utilized to estimate gestational age when dates are ambiguous or when women seek ultrasound fetal biometry dating during the third trimester itself.&#x0D; GA estimation is also a prerequisite to interpret certain tests (amniotic fluid assay, serum assay, chorionic villus sampling) and to plan timing of various forms of fetal therapy. Failure in estimating GA accurately can result in unnecessary induction, dysfunctional labor, operative delivery, iatrogenic prematurity or post maturity, false interpretation of tests and delay or failure of fetal therapy, thereby increasing perinatal morbidity and mortality.&#x0D; This review looks in to various studies assessing correlation of Fetal kidney length with gestational age in third trimester of pregnancy and provide a comprehensive view on use of Fetal kidney length for estimation of gestational age in third trimester of pregnancy.

Fetal Gestational Age Estimation Using Ultrasonic Transverse Cerebellar Diameter in a Sub-Saharan African Population.

To explore the relationship between fetal Transverse Cerebellar Diameter (TCD) and menstrual gestational age (GA) and to generate normative references (nomogram) of the fetal TCD in some pregnant women in Southwest Nigeria. Four hundred pregnant women with a singleton fetus between 14 and 38 weeks GA were enrolled. The TCD and other biometric parameters (biparietal diameter, head circumference, abdominal circumference, and femur length) as well as the cerebellar appearance were analyzed and correlated with the GA. The mean TCD increased from 13.3 ± 0.3 mm at 14 weeks to 52.3 ± 3.3 mm at 38 weeks of pregnancy. A strong positive correlation was observed between TCD and GA, which was best represented by a linear regression equation: Predicted GA = 0.557 × TCD + 8.840. The regression analysis indicated a statistically significant strong positive relationship between TCD and GA (r = 0.972 and P < 0.001). The cerebellar appearance based on shape and echogenicity was graded into Grade I: 230 fetuses (57.5%); Grade II: 74 fetuses (18.5%) and Grade III: 96 fetuses (24.0%). Median GA and TCD were 21 weeks and 21.2 mm for Grade I; 29 weeks and 35.5 mm for Grade II; and 35 weeks and 48.1 mm for Grade III, respectively. The TCD increased in a linear fashion with advancing GA in the evaluated fetuses. The TCD is, therefore, a good marker for GA estimation. There is a gradual ultrasonographic change in fetal cerebellar appearance with advancing gestation.

A new formula for estimating gestational age by crown-rump length

The accurate estimation of gestational age by ultrasound is crucial in prenatal care for the monitoring of fetal growth and development. As changes in maternal childbearing age, body habitus, and ultrasound technology occur, previously published formulas may not be accurate for today's population. This study aimed to develop new formulas for calculating the gestational age based on a first-trimester ultrasound scan and to compare the new formulas with preexisting formulas. This study was a single-center, retrospective observational study that included pregnancies conceived using in vitro fertilization. The pregnancies had known dates of embryo transfer and multiple standard ultrasound examinations in the first trimester of pregnancy. Pregnancies ending with a miscarriage or termination in the first trimester of pregnancy were excluded. A polynomial regression analysis was performed to determine the optimal model that represented the relationship between gestational age and crown-rump length. The models were evaluated using systematic error, random error, absolute difference of the calculated gestational age and actual gestational age, and proportion of estimation within 0 and 2 days of the known gestational age. The optimal model was chosen and compared with preexisting formulas. Overall, 1436 ultrasound results were included in the analysis. The analysis produced 3 models: linear, cubic, and quadratic models with correlation coefficients of 0.968, 0.989, and 0.991, respectively. The cubic formula was superior to the linear and quadratic formulas concerning systematic error, random error, absolute difference, and proportion of estimation within 0 and 2 days. The new formula had a lower systematic error, random error, and mean absolute difference (0.06%, 2.43%, and 0.97 days, respectively) and the highest proportion of estimation within 0 and 2 days (37.4% and 93.5%, respectively) than previously published formulas. The formula proposed in this study followed a cubic model and seemed to be able to more accurately estimate gestational age in the first trimester of pregnancy based on crown-rump length compared with previously published formulas.

Hierarchical Attentive Network for Gestational Age Estimation in Low-Resource Settings.

Assessing fetal development is essential to the provision of healthcare for both mothers and fetuses. In low- and middle-income countries, conditions that increase the risk of fetal growth restriction (FGR) are often more prevalent. In these regions, barriers to accessing healthcare and social services exacerbate fetal maternal health problems. One of these barriers is the lack of affordable diagnostic technologies. To address this issue, this work introduces an end-to-end algorithm applied to a low-cost, hand-held Doppler ultrasound device for estimating gestational age (GA), and by inference, FGR. The Doppler ultrasound signals used in this study were collected from 226 pregnancies (45 low birth weight at delivery) between 5 and 9 months GA by lay midwives in highland Guatemala. We designed a hierarchical deep sequence learning model with an attention mechanism to learn the normative dynamics of fetal cardiac activity in different stages of development. This resulted in a state-of-the-art GA estimation performance, with an average error of 0.79 months. This is close to the theoretical minimum for the given quantization level of one month. The model was then tested on Doppler recordings of the fetuses with low birth weight and the estimated GA was shown to be lower than the GA calculated from last menstruation. Thus, this could be interpreted as a potential sign of developmental retardation (or FGR) associated with low birth weight, and referral and intervention may be necessary.

Assessment of gestational age using anthropometric parameters in newborns

Background: Estimation of gestational age was needed for the measurement of intrauterine growth and associated conditions, such as whether infants with a low birth weight are preterm or growth-retarded, and identifying high-risk status for developmental delay. Menstrual history was unreliable in most of the cases and ultrasound was not feasible in low resource area, so in this study we were used anthropometric measurements as a simple tool for assessment of gestational age. Methods: This study was a cross sectional observational study conducted in 380 babies born in January 2020-December 2022 in department of pediatrics, Rajah Muthiah Medical College and Hospital. The data were collected using semi-structured questionnaire and anthropometric assessment. The Epi info 7 software was used to analyse the data. Results: The mean gestational age among neonates studied was 37.06±2.32 weeks, the mean head circumference was 33.48±1.01 cm and majority of them 141 babies had head circumference 33 cm, the mean chest circumference was 30.69±1.08 cm. and majority of the babies, had chest circumference of 30 cm, the mean foot length was 7.64±0.24 cm, the mean length of the babies was 47.9±1.26 cm. Conclusions: Our study conclude that anthropometeric parameters in combination (head, chest circumference, length, foot length, birth weight) and as single parameters (foot length) was a simple and easy tool for assessing gestational age in low resource setting where we can make quick referral.

ACCURACY OF FETAL KIDNEY LENGTH AND TRANSCEREBELLAR DIAMETER IN DETERMINATION OF FETAL GESTATIONAL AGE IN MID TRIMESTER IN HEALTHY WOMEN

Accurate assessment of gestational age (GA) is pivotal to provide good quality maternity care. Reliability of routinely used ultrasonographic biometric parameters like Biparietal diameter (BPD), Head circumference (HC) and Femur length (FL) decrease with increasing GA.Fetal kidney length (FKL) and transverse cerebellar diameter (TCD) have been shown to strongly correlate with GA in 2nd and 3rd trimester.The present study was conducted on 150 pregnant women at 20 weeks of gestation to evaluate the role of FKL and TCD in estimation of GA and compare their accuracy with other established biometric indices. The GA of the included women was confirmed by early dating scan and exact Last Menstrual Period (LMP).BPD,HC,FL,FKL and TCD were calculated in millimetres (mm) and GA was calculated by using these parameters individually. Standard deviation and standard error of the GA calculated at 20 weeks was lesser for TCD and FKL than BPD, HC and FL with p values of 0.01636 and 0.0129 respectively. It was also observed that values of TCD and FKL in mm correspond to GA in weeks. So it was concluded that FKL and TCD can be used as an individual parameter in estimating GA in mid trimester in patients presenting for the first time with uncertain dates, lack of early dating scan or with IUGR.

Machine learning for accurate estimation of fetal gestational age based on ultrasound images

Accurate estimation of gestational age is an essential component of good obstetric care and informs clinical decision-making throughout pregnancy. As the date of the last menstrual period is often unknown or uncertain, ultrasound measurement of fetal size is currently the best method for estimating gestational age. The calculation assumes an average fetal size at each gestational age. The method is accurate in the first trimester, but less so in the second and third trimesters as growth deviates from the average and variation in fetal size increases. Consequently, fetal ultrasound late in pregnancy has a wide margin of error of at least ±2 weeks’ gestation. Here, we utilise state-of-the-art machine learning methods to estimate gestational age using only image analysis of standard ultrasound planes, without any measurement information. The machine learning model is based on ultrasound images from two independent datasets: one for training and internal validation, and another for external validation. During validation, the model was blinded to the ground truth of gestational age (based on a reliable last menstrual period date and confirmatory first-trimester fetal crown rump length). We show that this approach compensates for increases in size variation and is even accurate in cases of intrauterine growth restriction. Our best machine-learning based model estimates gestational age with a mean absolute error of 3.0 (95% CI, 2.9–3.2) and 4.3 (95% CI, 4.1–4.5) days in the second and third trimesters, respectively, which outperforms current ultrasound-based clinical biometry at these gestational ages. Our method for dating the pregnancy in the second and third trimesters is, therefore, more accurate than published methods.

Birth weight and gestational age distributions in a rural Kenyan population

BackgroundWith the increased availability of access to prenatal ultrasound in low/middle-income countries, there is opportunity to better characterize the association between fetal growth and birth weight across global settings. This is important, as fetal growth curves and birthweight charts are often used as proxy health indicators. As part of a randomized control trial, in which ultrasonography was utilized to establish accurate gestational age of pregnancies, we explored the association between gestational age and birthweight among a cohort in Western Kenya, then compared our results to data reported by the INTERGROWTH-21st study.MethodsThis study was conducted in 8 geographical clusters across 3 counties in Western Kenya. Eligible subjects were nulliparous women carrying singleton pregnancies. An early ultrasound was performed between 6 + 0/7 and 13 + 6/7 weeks gestational age. At birth, infants were weighed on platform scales provided either by the study team (community births), or the Government of Kenya (public health facilities). The 10th, 25th, median, 75th, and 90th BW percentiles for 36 to 42 weeks gestation were determined; resulting percentile points were plotted, and curves determined using a cubic spline technique. A signed rank test was used to quantify the comparison of the percentiles generated in the rural Kenyan sample with those of the INTERGROWTH-21st study.ResultsA total of 1291 infants (of 1408 pregnant women randomized) were included. Ninety-three infants did not have a measured birth weight. The majority of these were due to miscarriage (n = 49) or stillbirth (n = 27). No significant differences were found between subjects who were lost to follow-up. Signed rank comparisons of the observed median of the Western Kenya data at 10th, 50th, and 90th birthweight percentiles, as compared to medians reported in the INTERGROWTH-21st distributions, revealed close alignment between the two datasets, with significant differences at 36 and 37 weeks. Limitations of the current study include small sample size, and detection of potential digit preference bias.ConclusionsA comparison of birthweight percentiles by gestational age estimation, among a sample of infants from rural Kenya, revealed slight differences as compared to those from the global population (INTERGROWTH-21st).Trial registrationThis is a single site sub-study of data collected in conjunction with the Aspirin Supplementation for Pregnancy Indicated Risk Reduction In Nulliparas (ASPIRIN) Trial, which is listed at ClinicalTrials.gov, NCT02409680 (07/04/2015).