Measurement Of Fetal Crown-rump Length Research Articles

Comparison of Fetal Crown-Rump Length Measurements between Thawed and Fresh Embryo Transfer.

Background and Objectives: Neonates born from thawed embryo transfers tend to have a significantly higher birthweight compared to those from fresh embryo transfers. The aim of this study was to compare the crown-rump length (CRL) between thawed and fresh embryos to investigate the potential causes of different growth patterns between them. Materials and Methods: This was a retrospective study (July 2010-December 2023) conducted at the Third Department of Obstetrics and Gynecology, School of Medicine, Faculty of Health Sciences, Aristotle University of Thessaloniki, Greece. In total, 3082 assisted reproductive technology (ART) pregnancies (4044 embryos) underwent a routine scan at 11+0-13+6 gestational weeks and were included in the study. Maternal age, the type of embryo transfer (thawed vs. fresh, donor vs. their own oocytes), CRL, twin and singleton gestations were analyzed. Results: The mean maternal age in thawed was significantly higher than in fresh embryos (39.8 vs. 35.8 years, p-value < 0.001). The mean CRL z-score was significantly higher in thawed compared to fresh embryo transfers (0.309 vs. 0.199, p-value < 0.001). A subgroup analysis on singleton gestations showed that the mean CRL z-score was higher in thawed blastocysts compared to fresh (0.327 vs. 0.215, p-value < 0.001). Accordingly, an analysis on twins revealed that the mean CRL z-score was higher in thawed blastocysts (0.285 vs. 0.184, p-value: 0.015) and in oocytes' recipients compared to own oocytes' cases (0.431 vs. 0.191, p-value: 0.002). Conclusions: The difference in CRL measurements between thawed and fresh embryos may be a first indication of the subsequent difference in sonographically estimated fetal weight and birthweight. This finding highlights the need for additional research into the underlying causes, including maternal factors and the culture media used.

Reappraising the Value of Fetal First-Trimester Ultrasonography

Abstract In the last few years, the introduction of cell-free DNA has rapidly altered prenatal screening regimens and is increasingly offered as the second- or, at times, even the first-tier screening test. Should an early anomaly scan also be part of an up-to-date screening policy? This paper reappraises the value of fetal first-trimester ultrasonography. The primary aims of the first-trimester scan are to establish gestational age based on the measurement of fetal crown-rump length, to detect multiple pregnancy and chorionicity, and to measure fetal nuchal translucency thickness as part of a combined screening test for chromosomal abnormalities. With recent advancements in ultrasound technology, there is compelling evidence that a majority of fetuses with major structural abnormalities and almost half of them without chromosomal abnormalities can be detected in the first trimester. We focused on the first-trimester screening of fetal major defects, especially including fetal congenital heart disease and cleft lip and palate by ultrasound markers and views. Moreover, it is critical to highlight that after a detailed anomaly scan in the first trimester without major structural anomalies and positive genetic tests, the residual chance of favorable outcome in fetuses with isolated increased nuchal translucency is relatively high. The discussion on the role of cell-free DNA in prenatal screening is still ongoing. Even in the event of it becoming a first-line screening test for aneuploidies, the importance of a first-trimester fetal scan, including assessment of markers for other anomalies, remains undisputed.

Crown-rump length measurement error: impact on assessment of growth.

To examine the impact of first-trimester crown-rump length (CRL) measurement error on the interpretation of estimated fetal weight (EFW) and classification of fetuses as small-, large- or appropriate-for-gestational age on subsequent growth scans. We examined the effects of errors of ± 2, ± 3 and ± 4 mm in the measurement of fetal CRL on percentiles of EFW at 20, 32 and 36 weeks' gestation and classification as small-, large- or appropriate-for-gestational age. Published data on CRL measurement error were used to determine variation present in practice. A measurement error of -2 mm in first-trimester CRL shifts an EFW on the 10th percentile at the 20-week scan to around the 20th percentile, and the effect of a CRL measurement error of + 2 mm would shift an EFW on the 10th percentile to around the 5th percentile. At 32 weeks, a first-trimester CRL measurement error would shift an EFW on the 10th percentile to the 7th (+ 2 mm) or 14th (-2 mm) percentile; at 36 weeks, the EFW would shift from the 10th percentile to the 8th (+ 2 mm) or 12th (-2 mm) percentile. Published data suggest that measurement errors of 2 mm or more are common in practice. Because of the widespread and potentially severe consequences of CRL measurement errors as small as 2 mm on clinical assessment, patient management and research results, there is a need to increase awareness of the impact of CRL measurement error and to reduce measurement error variation through standardization and quality control. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Doppler reference values in women with a normal body mass index

To construct gestation specific reference limits for fetal umbilical (UA), middle cerebral artery (MCA) pulsatility indices (PI) and the cerebroplacental ratio (CPR) in singleton pregnancies with normal BMI between 16 and 40 weeks of gestation. We ultrasonographically examined 596 fetuses from women with normal nutritional and health status and minimal environmental constraints on fetal growth. Each mother was considered only once for measurement of fetal Doppler indices, at gestations between 16 and 40 weeks in a prospective cross-sectional study. Gestational age was confirmed by fetal crown-rump length measurement between 11 and 14 weeks. Pulsatility indices of umbilical and middle cerebral arteries were measured by real time and Doppler ultrasonography. CPR ratio was calculated by dividing MCA PI by UA PI. The fetal Doppler measurements obtained from the current study were compared with commonly used reference charts. For each parameter separate polynomial regression models were fitted to estimate the gestation specific means and standard deviations, assuming that the measurements have a normal distribution at each gestational age. A significant difference of fetal Doppler indices was observed between our study and previously published reference charts for most gestational weeks. The fitted 10th, 50th and 90th centiles at 40 weeks of gestation were 0.65, 0.87 and 1.08 for UA PI; 0.93, 1.32 and 1.71 MCA PI; 1.02, 1.58 and 2.13 for CPR. These charts can be used for better defining the normal range of fetal arterial Doppler indices. This will be useful in the diagnosis and management of fetuses with abnormal fetal growth.

Effects of trimester-specific exposure to vanadium on ultrasound measures of fetal growth and birth size: a longitudinal prospective prenatal cohort study

Identification of windows of heightened vulnerability to environmental factors has substantial public health implications. Prenatal exposure to vanadium has been linked to adverse birth outcomes; however, critical windows for such exposure during fetal growth remain unknown. We aimed to assess trimester-specific associations of vanadium exposure with ultrasound measures of fetal growth and birth size in a Chinese longitudinal cohort. The present study was embedded in our ongoing prospective prenatal cohort study at the Wuhan Women and Children Medical Care Center (Wuhan, Hubei, China). Pregnant women were eligible for inclusion if they provided signed informed consent and were less than 16 weeks pregnant with a single gestation, and agreed to take in-person interviews, undergo ultrasound examinations, and provide blood and urine samples. We collected urine samples and measured urinary vanadium concentrations using inductively coupled plasma mass spectrometry. We calculated SD scores for ultrasound-measured biparietal diameter, head circumference, occipitofrontal diameter, abdominal circumference, femur length, and estimated fetal weight at 16, 24, and 31 weeks of gestation. We applied linear regressions with generalised estimating equations to estimate associations of urinary vanadium concentrations in each trimester with ultrasound-measured fetal growth parameters or neonatal size at birth. As of Oct 12, 2016, we recruited 3075 women who were non-smokers and non-drinkers during pregnancy, provided up to three urine samples during the first, second, and third trimesters, and gave birth to live singletons without birth defects. We excluded women who did not provide information on ultrasound measurements (n=20) or who only had one ultrasound measurement of fetal crown-rump length at the first trimester (n=14). We excluded another 16 women because they had missing values for confounding variables, leaving 3025 women retained in the study. Every doubling of urinary vanadium concentration in the first trimester was associated with a significant increase in femur length (adjusted percentage change 6·4%, 95% CI 0·7 to 12·1) at 16 weeks of gestation and reductions in biparietal diameter (-4·2%, -8·2 to -0·1), head circumference (-6·0%, -10·1 to -1·9), occipitofrontal diameter (-5·7%, -9·9 to -1·5), and abdominal circumference (-5·3%, -9·4 to -1·2) at 31 weeks of gestation. Every doubling of urinary vanadium concentration in the second trimester was significantly associated with reductions in SD scores for head circumference (-7·2%, -14·1 to -0·3) and abdominal circumference (-6·9%, -13·8 to -0·1) at 31 weeks of gestation. The highest quartile of urinary vanadium concentration (>1·18 μg/L) in the first trimester, when compared with the lowest quartile (≤0·60 μg/L), was associated with a mean decrease in birthweight of 12·6 g (95% CI 2·5-22·8; ptrend=0·0055) and a mean decrease in ponderal index of 0·07 kg/m3 (0·01-0·12; ptrend=0·0053). Moreover, newborns with restricted birth size had higher vanadium exposure in the first and third trimesters. Vanadium might be toxic to humans and impair fetal growth. The first, early second, and late third trimesters could be critical windows for heightened vulnerability to vanadium for fetal growth. Our findings require further investigation in other populations. National Key R&D Plan of China, National Natural Science Foundation of China, and Fundamental Research Funds for the Central Universities, Huazhong University of Science and Technology.

Sonographic detection of open spina bifida in the first trimester: review of the literature.

In the beginnings, sonographic diagnosis of open spina bifida (OSB) relied on the meticulous scanning of the fetal vertebrae for abnormalities but many defects were missed. After the mid-1980s, however, with the description of the intracranial findings in the second trimester (the "lemon sign" and the "banana sign"), the prenatal diagnosis of OSB was enhanced. In the last 2 decades, there has been widespread uptake of routine ultrasound examination in the first trimester of pregnancy with the purpose of the measurement of fetal crown-rump length to determine gestational age, to screen for trisomy 21 and other aneuploidies, mainly with the nuchal translucency, and for diagnosis of many major abnormalities. Many papers were published focusing on early diagnosis of myelomeningocele (MMC), and the objective of this review is to summarize the different techniques described regarding prenatal diagnosis of OSB in the first trimester of pregnancy.

Comparison of ultrasound fetal biometry of singleton fetuses with a reference chart in pregnant women with normal nutritional and health status

The aim of this study was to compare fetal biometry of singleton fetuses in pregnant women with normal nutritional and health status in the Ampara district, with a commonly used reference chart. A cross sectional study was carried out in the Ampara District. Women with normal nutritional and health status and minimal environmental constraints on fetal growth (n=714) were enrolled during the first trimester and gestational age was confirmed by fetal crown-rump length measurement between 11 weeks + 0 days and 13 weeks + 6 days. For this study, each mother was considered only once for measurement of fetal biometry, at gestations between 11 and 41 weeks. Fetal bi-parietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL) were measured using standard techniques, and separate regression models were fitted to estimate the means and standard deviations and derive gestation specific centiles for each parameter, assuming that the measurements have a normal distribution at each gestational age. The fetal biometry results obtained from the current study were compared with a commonly used reference chart. The fitted 10th, 50th and 90th centiles at 40 weeks of gestation were, 87.9 mm, 93.2 mm and 98.5 mm for BPD, 313.8 mm, 328.9 mm and 344.0 mm for HC; 298.2 mm, 322.5 mm and 346.9 mm for AC and 69.7 mm, 75.0 mm and 80.2 mm for FL. When compared with the reference chart, significant differences of fetal biometry were seen in the third trimester but not in the second trimester. Ultrasound fetal biometry of singleton fetuses in pregnant women with normal nutritional and health status in the Ampara District were significantly different in the third trimester, from a routinely used reference chart.

Symphysis-pubis fundal height charts to assess fetal size in women with a normal body mass index.

To construct symphysis-pubis fundal height (SFH) charts to estimate fetal size in pregnant women with a normal body mass index (BMI) and to describe the variation of SFH measurements according to BMI. cross sectional study was carried out at Ampara and Gampaha Districts in Sri Lanka. Women with normal nutritional and health status, normal BMI and minimal environmental constraints on fetal growth, with ultra sound confirmation of dates by fetal crown-rump length measurements between 11 weeks and 13 weeks + six days,had their SFH measured, using non-elastic tape and standard techniques, between 24 and 41 weeks gestation. Only one measurement of SFH was obtained from each pregnant woman. Linear and polynomial regression models were fitted separately to the means and standard deviations (SD) as functions of gestational age to identify the model with the best fit. Centiles were derived from the mean and SD at each gestational age. Pregnant women from the districts of Ampara (n=387) and Gampaha (n=200) were recruited. Other than a difference of -1.5 cm (95% CI -2.27 to -0.23) at 38 weeks of gestation, there were no significant differences between the SFH measurements obtained from women with normal BMI in Ampara and Gampaha Districts. Using the SFH measurements from the Ampara sample, charts were created for 10th, 50th and 90th centile values of SFH. At 40 weeks of gestation these were 34 cm, 37 cm and 41 cm respectively. At 40 weeks gestation, the variation in SFH measurements between BMI sub groups within the normal range was approximately 1.4 cm to 1.6 cm. These SFH charts could be used to estimate fetal size in pregnant women with normal BMI.

Gestational length assignment based on last menstrual period, first trimester crown-rump length, ovulation, and implantation timing.

PurposeUnderstanding the natural length of human pregnancy is central to clinical care. However, variability in the reference methods to assign gestational age (GA) confound our understanding of pregnancy length. Assignation from ultrasound measurement of fetal crown-rump length (CRL) has superseded that based on last menstrual period (LMP). Our aim was to estimate gestational length based on LMP, ultrasound CRL, and implantation that were known, compared to pregnancy duration assigned by day of ovulation.MethodsProspective study in 143 women trying to conceive. In 71 ongoing pregnancies, gestational length was estimated from LMP, CRL at 10–14 weeks, ovulation, and implantation day. For each method of GA assignment, the distribution in observed gestational length was derived and both agreement and correlation between the methods determined.ResultsMedian ovulation and implantation days were 16 and 27, respectively. The gestational length based on LMP, CRL, implantation, and ovulation was similar: 279, 278, 276.5 and 276.5 days, respectively. The distributions for observed gestational length were widest where GA was assigned from CRL and LMP and narrowest when assigned from implantation and ovulation day. The strongest correlation for gestational length assessment was between ovulation and implantation (r = 0.98) and weakest between CRL and LMP (r = 0.88).ConclusionsThe most accurate method of predicting gestational length is ovulation day, and this agrees closely with implantation day. Prediction of gestational length from CRL and known LMP are both inferior to ovulation and implantation day. This information could have important implications on the routine assignment of gestational age.

International standards for fetal growth based on serial ultrasound measurements: the Fetal Growth Longitudinal Study of the INTERGROWTH-21st Project

In 2006, WHO produced international growth standards for infants and children up to age 5 years on the basis of recommendations from a WHO expert committee. Using the same methods and conceptual approach, the Fetal Growth Longitudinal Study (FGLS), part of the INTERGROWTH-21(st) Project, aimed to develop international growth and size standards for fetuses. The multicentre, population-based FGLS assessed fetal growth in geographically defined urban populations in eight countries, in which most of the health and nutritional needs of mothers were met and adequate antenatal care was provided. We used ultrasound to take fetal anthropometric measurements prospectively from 14 weeks and 0 days of gestation until birth in a cohort of women with adequate health and nutritional status who were at low risk of intrauterine growth restriction. All women had a reliable estimate of gestational age confirmed by ultrasound measurement of fetal crown-rump length in the first trimester. The five primary ultrasound measures of fetal growth--head circumference, biparietal diameter, occipitofrontal diameter, abdominal circumference, and femur length--were obtained every 5 weeks (within 1 week either side) from 14 weeks to 42 weeks of gestation. The best fitting curves for the five measures were selected using second-degree fractional polynomials and further modelled in a multilevel framework to account for the longitudinal design of the study. We screened 13,108 women commencing antenatal care at less than 14 weeks and 0 days of gestation, of whom 4607 (35%) were eligible. 4321 (94%) eligible women had pregnancies without major complications and delivered live singletons without congenital malformations (the analysis population). We documented very low maternal and perinatal mortality and morbidity, confirming that the participants were at low risk of adverse outcomes. For each of the five fetal growth measures, the mean differences between the observed and smoothed centiles for the 3rd, 50th, and 97th centiles, respectively, were small: 2·25 mm (SD 3·0), 0·02 mm (3·0), and -2·69 mm (3·2) for head circumference; 0·83 mm (0·9), -0·05 mm (0·8), and -0·84 mm (1·0) for biparietal diameter; 0·63 mm (1·2), 0·04 mm (1·1), and -1·05 mm (1·3) for occipitofrontal diameter; 2·99 mm (3·1), 0·25 mm (3·2), and -4·22 mm (3·7) for abdominal circumference; and 0·62 mm (0·8), 0·03 mm (0·8), and -0·65 mm (0·8) for femur length. We calculated the 3rd, 5th 10th, 50th, 90th, 95th and 97th centile curves according to gestational age for these ultrasound measures, representing the international standards for fetal growth. We recommend these international fetal growth standards for the clinical interpretation of routinely taken ultrasound measurements and for comparisons across populations. Bill & Melinda Gates Foundation.

Impact of ovulation and implantation timing on first‐trimester crown–rump length and gestational age

To determine the impact of ovulation and implantation timing on first-trimester crown-rump length (CRL) and the derived gestational age (GA). One hundred and forty-three women who were trying to conceive were recruited prospectively. The timing of ovulation and implantation and the ovulation to implantation (O-I) interval were established in 101 pregnancies using home urinary tests for luteinizing hormone and human chorionic gonadotropin. In 71 ongoing pregnancies, GA determined by measurement of fetal CRL at 10-14 weeks' gestation was compared with GA based on ovulation and implantation day. First-trimester growth was determined by serial ultrasound scans at 6-7, 8-9 and 10-14 weeks. The median ovulation and implantation days were 16 and 27, respectively, with an O-I interval of 11 days. GA estimated from CRL at 10-14 weeks was on average 1.3 days greater than that derived from ovulation timing. CRL Z-score was inversely related to O-I interval (ρ= -0.431, P=0.0009). There was no significant relationship between CRL growth rate and the difference between observed CRL and expected CRL based on GA from last menstrual period (ρ=0.224, P=0.08). Early implantation leads to a larger CRL and late implantation to a smaller CRL at 10-14 weeks, independent of CRL growth rate. Implantation timing is a major determinant of fetal size at 10-14 weeks and largely explains the variation in estimates of GA in the first trimester derived from embryonic or fetal CRL.

Fetal growth in early pregnancy and risk of delivering low birth weight infant: prospective cohort study

Objective To determine if first trimester fetal growth is associated with birth weight, duration of pregnancy, and the risk of delivering a small for gestational age infant.Design Prospective cohort study...

Human Sexual Size Dimorphism in Early Pregnancy

Sexual size dimorphism is thought to contribute to the greater mortality and morbidity of men compared with women. However, the timing of onset of sexual size dimorphism remains uncertain. The authors determined whether human fetuses exhibit sexual size dimorphism in the first trimester of pregnancy. Using a prospective cohort study, conducted in 1999-2002 in the United States, they identified 27,655 women who conceived spontaneously and 1,008 whose conception was assisted by in vitro fertilization or intrauterine insemination and for whom a first-trimester measurement of fetal crown-rump length was available. First-trimester size was expressed as the difference between the observed and expected size of the fetus, expressed as equivalence to days of gestational age. The authors evaluated the association between fetal sex, first-trimester size, and birth weight. Eight to 12 weeks after conception, males were larger than females (mean difference: assisted conception = 0.4 days, 95% confidence interval (CI): 0.1, 0.7, p = 0.008; spontaneous conception = 0.3 days, 95% CI: 0.2, 0.4, p < 0.00001). The size discrepancy remained significant at birth (mean birth weight difference: assisted conception = 90 g, 95% CI: 22, 159, p = 0.009; spontaneous conception = 120 g, 95% CI: 107, 132, p < 0.00001). These data demonstrate that human fetuses exhibit sexual size dimorphism in the first trimester of pregnancy.

First‐trimester fetal limb biometry in Chinese population

To establish reference ranges for fetal limb biometry obtained by transabdominal ultrasound examination at 12-14 weeks of gestation in Chinese women. A total of 1489 normal singleton fetuses between 12(+0) and 14(+6) weeks of gestation were examined transabdominally by two experienced observers. The gestation was ascertained by measurement of fetal crown-rump length (CRL) or biparietal diameter (BPD) and head circumference (HC). The lengths of the humerus and femur were prospectively worked out. Gestation-specific reference ranges for limb measurements were calculated. The femur length (FL) (mean +/- SD) was 9.15 +/- 1.44 mm at 12-12(+6) weeks, 11.45 +/- 1.35 mm at 13-13(+6) weeks, and 13.64 +/- 1.60 mm at 14-14(+6) weeks; the corresponding humerus length (HL) (mean +/- SD) was 9.63 +/- 1.44 mm, 12.01 +/- 1.41 mm, 14.29 +/- 1.48 mm, respectively. There was a general increase in fetal limb biometry with gestation. Fetal limb length can be an early marker of early growth restriction as well as fetal skeletal dysplasia among women in the local population.

Accuracy of Gestational Age Estimation by Means of Fetal Crown-Rump Length Measurement

Accuracy of Gestational Age Estimation by Means of Fetal Crown-Rump Length Measurement

Accuracy of gestational age estimation by means of fetal crown-rump length measurement

The purpose of this study was to develop a gestational age table by means of crown-rump length measurements in the first trimester in pregnancies conceived through in vitro fertilization. Ninety-four infertile women with singleton intrauterine pregnancies resulting from in vitro fertilization underwent ultrasonographic examinations in the first trimester. The relationship between gestational age (calculated with the day of oocyte retrieval used as day 14) and the crown-rump length was explored with regression analysis. A quadratic model demonstrated the best fit to the data, indicating a curvilinear relationship between crown-rump length and gestational age. Estimates of gestational age with crown-rump length measurements between 40 and 60 mm were observed to be similar to published tables, but outside this range the tables either overestimate or underestimate the true gestational age. A more accurate equation for gestational age estimation with crown-rump length measurements in early pregnancy has been developed with in vitro fertilization pregnancy data.

The accuracy of ultrasonic measurement of fetal crown-rump length

Routine ultrasonic crown-rump length measurements were retrospectively evaluated in an antenatal clinic using maternal body temperature graphs as reference to ovulatory age. A comparison with the original figures of Robinson is made. Potential errors are discussed. The conlusion is that one should be very careful in interpreting an ultrasonic CRL measurement before 10 weeks menstrual age because of both measurement and operator errors.

Crown-rump length and serum human chorionic gonadotropin as predictors of gestational age.

The accuracy of fetal crown-rump length measurement and maternal serum human chorionic gonadotropin (hCG) concentration in the prediction of obstetric gestational age was analyzed in a study population of 77 patients for whom time of ovulation was reliably determined. Published nomograms relating maternal serum hCG concentration to gestational age were not found to be valid predictors of gestational age for the study population. Fetal crown-rump length measurement using the uncorrected regression equation of Robinson was found to give the most accurate prediction of gestational age.

The ultrasonic measurement of fetal crown-rump length as a method of assessing gestational age.

The fetal crown-rump length (CRL) was measured by means of pulsed ultrasound, and the normal values between 47 and 101 days from the onset of the last menstrual period were determined from cross-sectional data in 253 patients. For any given CRL, the range was found to be within three days of the menstrual age with a maximum variation for a given occasion of three days. Detailed statistical analysis showed that the acceleration in the rate of change in the CRL was a constant and that the intrapatient variability, where measured, was low. A close correlation between the measurement and the date of ovulation was demonstrated in a further 40 patients.

"Gestation sac" volumes as determined by sonar in the first trimester of pregnancy.

Sonar estimates of "gestation sac" volumes in the first trimester of pregnancy were made from a series of 319 measurements; the volumes estimated included the amniotic fluid, the extraembryonic coelom and the fetus. The technique employed involved the use of parallel section scans taken in series from one end of the gestation sac to the other, followed by planimetric measurements of the sac areas so produced. The potential errors which may be incurred in these measurements are discussed, and it is considered that the technique carries an overall possible error in the order of plus or minus 10 per cent. Growth curves produced from the measurements in this series show that the sac increases in volume from a mean of 1 ml. at 6 weeks to a mean of 100 ml. at 13 weeks, initially in an exponential fashion but latterly in a more linear manner. The mean values of the sonar gestation sac fluid volumes (after subtraction of the estimated fetal volume) in the 10 to 13 week range, show good correlation with those amniotic fluid values reported in the literature where direct measurements were made at the time of hysterotomy. As a method of assessing the maturity of a pregnancy this technique is of lesser value than the sonar measurement of fetal crown-rump length because of the relatively wider scatter of results. It has, however, found a useful place in clinical practice in the early sonar diagnosis of blighted ova or anembryonic pregnancies.