Ultrasonic Estimation Of Fetal Weight Research Articles

Accuracy of Ultrasound Determination of Estimated Fetal Weight in Small for Gestational Age Pregnancies

Background: Ultrasound is more accurate when it follows clinical diagnosis of intrauterine growth restriction. Based on the review of literature, we recommend routine ultrasound examination in the third trimester for timely diagnosis of SGA. Aims & Objectives: This study was done to assess the accuracy of ultrasound examination in estimation of fetal weight from 37 weeks to 40 weeks of pregnancy in appropriate for gestational age and small for gestational age. Material & Methods: The prospective randomized observational study whereby all ultrasonic fetal weight estimations were carried by prosound i4 ALOKA. Fifty pregnant women at term with appropriate for gestational age pregnancy and fifty other women at term with small for gestational age pregnancy had ultrasonic estimation of fetal weight performed within a week of delivery. Results: The present study showed that majority of subjects of control and study group were in the age group 21 to 30 years and co-efficient of correlation (r) = 0.6981 suggest high positive correlation between actual birth weight and estimated fetal weight by ultrasound. Conclusion: The study showed that ultrasound predicts the fetal weight in both categories with a mean absolute error of 1.092435 USG estimation of fetal weight can be used to predict the birth weight with high degree of accuracy and plan delivery and neonatal management for a better neonatal outcome.

The Estimation Model of Fetal Weight Based on BP Network

The ultrasonic estimation of fetal weight at delivery is of important prognostic significance in obstetrical practice. The conventional regression formulas used for estimating fetal weight have the disadvantage of less reliability. In this paper,it used the BP network to estimate fetal weight. Some input variables were adopted in constructing the BP model-gestational age(GA), biparietal diameter(BPD), femur length(FL), abdominal circumference(AC). Fetal weight was as output variable in the model. It constructed 4—7—1 network topology to estimate by using 130 clinical datas.The result is that coincidence rate was 99%, mean absolute error was 37.72g, mean relative error was 3.60% in the training group; In the validation group, coincidence rate was 96.67%, mean absolute error is 74.11g, Mean relative error was 4.71%;Comparing with the predictive effect of 3 conventional regression formulas, BP network is very valuable, which has higher accuracy rate.

Noncardiogenic Pulmonary Edema Due to Ritodrine Usage in Preterm Labor

A 34-year-old woman at 28 weeks of gestation presented at the emergency department of our hospital with shortness of breath, cough, sweating, and deterioration of consciousness, which had begun 3 days ago. The history given by her relatives revealed that she had received intravenous ritodrine (later found to be in the form of a constant infusion at 60 µg/min for 2 days) together with two doses of betamethasone (Celestone, Schering) at 12-hour intervals for accelerating fetal lung maturation in a private clinic. After this initial intervention, treatment was continued with oral tocolytic tablets (ritodrine tablets). There was nothing else notable in her medical history. Physical examination of the unconscious patient revealed a body temperature of 37.2°C, arterial blood pressure of 90/60 mmHg, pulse rate of 142/min, and respiration rate of 27/min, with hyperventilation and slight rales over bilateral lungs. She was intubated immediately. Fetal measurements were concordant with a 28-week pregnancy, and the amount of amniotic fluid was found to be normal. Ultrasonic estimation of fetal weight was 1,100 g. The hemoglobin level, hematocrit, leukocyte count and platelet counts were 12 g/dL, 37.2%, 9.100/mm 3 and 223,000/mm 3 , respec

Sonographic Diagnosis of Fetal Growth Restriction

Though a number of ultrasonic methods of diagnosing intrauterine growth restriction (IUGR) exist, the combined use of Doppler velocity wave form analysis of fetal vessels and the ultrasonic estimation of fetal weight (or abdominal circumference) appears to be the best method of both identification and evaluation of IUGR. Once identified, the IUGR fetus should undergo serial evaluation every two weeks or on a weekly schedule (or more frequent interval if the clinical situation warrants) with both Doppler velocity wave form studies and biophysical testing. Determination of the optimal time of delivery depends not only on the results of the antenatal testing, but also on the individual clinical situation. Fetal venous Doppler studies may give additional information about the time frame and significance of the IUGR.

Ultrasonic estimation of fetal weight at term: An evaluation of eight formulae

To compare the accuracy of eight sonographic formulae for predicting fetal birth weight at term in a multiethnic population. Pregnant women at term who were booked for induction of labor or elective cesarean section were included in the study. Eight ultrasonic fetal biometric formulae were used to predict fetal birth weight. A total of 173 patients were included in the study; 53 (30.6%) patients were from the Indian subcontinent, 44 (25.4%) patients were from Africa, 33 (19.1%) patients were from the Arabian Peninsula and 43 (24.9%) were from other ethnic groups. The mean absolute error ranged from a minimum of 0.3% (+/-11.3) for Hadlock (biparietal diameter [BPD], head circumference [HC], abdominal circumference [AC], femur length [FL]) to a maximum of 37.5% (+/-10.0) for Warsof (FL). The correlation of estimated fetal weight with actual birth weight ranged from a minimum of 0.09 with Warsof (FL) to a maximum of 0.77 with Shepard and Warsof (BPD, AC) and Hadlock (BPD, HC, AC, FL). The combination of AC with BPD measurements rather than FL achieves a high level of accuracy. Shepard (BPD, AC) provides a simple and accurate logarithm for the prediction of fetal weight at term in the studied multiethnic population.

Accuracy of ultrasonic fetal weight estimation using head and abdominal circumference and femur length

Former investigations have shown that the accuracy of fetal weight estimation is significantly higher if several ultrasonic fetal parameters are measured, because the total body mass depends on the size of fetal head, abdominal circumference and femur length. The aim of this investigation was to establish the best regression model, that is a number of combinations of fetal parameters providing the most accurate fetal weight estimation in utero in our population. This prospective study was carried out at the Gynecology and Obstetrics Clinic of the Clinical Center Novi Sad. It included 270 pregnant women with singleton pregnancies within 72 hours of delivery who underwent ultrasound measurements of the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL). In regard to fetal weight estimation formulas, the deviation was lowest using regression models that simultaneously analyzed four fetal parameters (0. 55%) with SD +/- 7.61%. In these models the estimates of fetal weights were within +/- 5% of actual birth weight in 48.89%, and within +/- 10% of actual birth weight in 81.48%. Good results were also obtained using AC, FL measurements (0.92% +/- 8.20) as well as using AC, HC, FL measurements (-1.45% +/- 7.81). In our sample the combination of AC and FL model gave better results in fetal weight estimation (0.92 +/- 8.20%) than the one using BPD and AC (2.97 +/- 8.83%). Furthermore, the model using parameters AC, HC and FL showed a lower error in accuracy (-1.45 +/- 7.81%) than the model using BPD, AC and FL (2.51 +/- 7.82%). This investigation has confirmed that the accuracy of fetal weight estimation increases with the number of measured ultrasonic fetal parameters. In our population the greatest accuracy was obtained using BPD, HC, AC and FL model. In cases when fast estimation of fetal weight is needed, AC, HC, FL model may be appropriate, but if fetal head circumference cannot be measured (amnion rupture and/or fetal head already in the pelvis) the AC, FL model should be used.

Decreased accuracy in fetal weight estimation in women with obesity or polyhydramnios

OR POLYHYDRAMNIOS CUNEYT OZCAN, AVRAHAM OREN, YUVAL GIELCHINSKY, CHEN SELA, VANIA WALLACH, RACHEL PICARD, ORLY SHOSHANI, DAVID MANKUTA, Hadassah University Hospital Jerusalem, Obstetrics and Gynecology, Jerusalem, Israel, Hadassah University Hospital Jerusalem, Center for quality and Safety, Jerusalem, Israel OBJECTIVE: To study the accuracy of clinical and ultrasonic fetal weight estimation in women with obesity or with polyhydramnios. STUDY DESIGN: In a prospective study, 270 singleton pregnancies between 37 and 42 weeks had clinical (Leopold) and sonographic (Hadlock) fetal weight estimation. All pregnant women were within one week of delivery .The patients were stratified into 3 groups: 100 Obese pregnant women (BMI >30 and normal AFI), 70 normal weight women with polyhydramnios (AFI >20) and 100 controls with normal weight and normal amniotic fluid (BMI !26 and AFI !20). Clinical estimations were performed by a resident and a specialist in obstetrics or MFM. All observers were blinded to all other estimation results. Absolute percent error was calculated for each specific method. RESULTS: The accuracy of the clinical estimation was greatest in the control group; it declined in the polyhydramnios group and was significantly worse in the obese group (P = .04). There were no significant differences between the clinical estimation of residents and specialists. In the clinical estimation method physicians have a tendency to underestimate the fetal weight (P = .04) while in the obese group to overestimate the fetal weight (P = .05).Sonographic estimation was not more accurate than the clinical. CONCLUSION: When the pregnant women’s abdomen is large due to obesity or polyhydramnios, the accuracy of clinical fetal weight estimation is significantly reduced. This information may be important for clinical decisionmaking, patient consultation as well as medico legal aspects.

OC192: The effect of maternal, paternal and fetal characteristics on the sonographic estimations of fetal weight

To assess the influence of maternal, paternal and fetal characteristics on the sonographic estimations of fetal weight (EFW), predicted by different formulas. Data were collected from women who delivered a live singleton at University College London Hospital within one week after their last ultrasound. The sonographic EFW was calculated by four formulas. Maternal, paternal and fetal characteristics were obtained from hospital records. Bland and Altman plots to show limits of agreement, intraclass correlation coefficients and multivariate regression models were used as statistical methods. 1191 deliveries were eligible for analysis. Mean interval between ultrasound and delivery was 2.9 days (±2.1 (SD)), mean gestational age at delivery was 273.0 days ± 26.4 (range 156–301) and birth weight 3179 gm ± 893.3 (range 417–5500 gm). 69% of the women and 64% of the men were Caucasian. The Shepard formula overestimated with a mean difference of 137.2 gm (range between the limits of agreement −661 to 935.5 gm), the Hadlock, Campbell and Scott formula all underestimated with different limits of agreement (respectively −93.6 gm (−836.6 to 649.1), −169 gm (−909.7 to 571.7), −551.4 gm (−1328.3 to 225.5)). Accuracy of prediction of EFW decreased with increasing gestational age and birth weight. Gestational age affected the accuracy of the four EFW formulas to a different extent. Maternal age, height, weight, BMI, smoking status, ethnicity and paternal ethnicity did not change the estimations of EFW to a large extent. Of the fetal characteristics gender and AFI did not change the estimations. The validity of ultrasonic estimation of fetal weight in this large population with the four formulas was reasonable. The accuracy of ultrasound estimation of fetal weight is affected by gestational age and birth weight and to a smaller extent by maternal, paternal and other fetal characteristics.

Ultrasonic fetal weight estimation in women with pregnancy complicated by diabetes

Ultrasonic fetal weight estimation in women with pregnancy complicated by diabetes

Delivery of the macrosomic infant: Cesarean section versus vaginal delivery

The macrosomic fetus of a diabetic woman faces increased risk for injury at the time of birth. Cesarean section offers the potential for avoiding trauma to the fetus, but can result in increased morbidity in the mother as compared to vaginal delivery. In this article, the advantages and disadvantages of the 2 routes of delivery for the overgrown fetus of a diabetic mother are discussed. In addition, methods for diagnosing macrosomia by ultrasound are examined, along with the benefits and pitfalls of ultrasonic fetal weight estimation in the setting of diabetes. Finally, management approaches for selecting route of delivery for the macrosomic fetus are described and analyzed.

Choosing route of delivery for the macrosomic infant of a diabetic mother: Cesarean section versus vaginal delivery

The macrosomic fetus of a diabetic woman faces increased risk for injury at the time of vaginal birth. Cesarean section offers the promise of avoiding trauma to the fetus, but can result in increased morbidityin the mother as compared to vaginal delivery. In this article, the advantages and disadvantages of the two routes of delivery for the overgrown fetus of a diabetic mother are discussed. Specifically, dataregarding risk of permanent neurological damage to the infant from vaginal delivery, and maternal morbidity from elective, pre-labor Cesarean delivery are critically examined. In addition, methods for diagnosingmacrosomia by ultrasound are discussed, along with the benefits and pitfalls of ultrasonic fetal weight estimation in the setting of diabetes. Finally, management approaches for selecting route of deliveryfor the macrosomic fetus are described and analyzed.

Validity of ultrasound estimation of fetal weight

Objective: To assess the validity of ultrasound estimation of fetal weight at term. Methods: We conducted a prospective observational study whereby all ultrasonic biometric measurements were done by a single observer. Fifty pregnant women at term had ultrasonic measurement of various fetal biometric parameters performed within a week of delivery. Fetal weight was estimated by the use of four reported methods (Aoki, Campbell, Shepard, and Hadlock formulas). We compared estimated weight with the birth weight after the estimated fetal weight was adjusted by adding 25 g for each day between the ultrasound measurements and delivery. Results: The adjusted estimated fetal weight obtained from all four formulas tended to be lower than measured birth weight. The smallest mean difference was obtained with the Shepard and Aoki formulas (51.4 g and 60.5 g, respectively), whereas the Campbell and Hadlock formulas produced larger mean differences (141.8 g and 190.7 g, respectively). The Aoki formula generated the smallest range between the limits of agreement (−324.2 to 445.2 g) whereas the Campbell formula produced the largest range (−286.5 to 570.1 g). The range between the limits of agreement generated with the Shepard and Hadlock formulas were intermediate between those produced by the Aoki and Campbell formulas. The intraclass correlation coefficients generated with the Aoki and Shepard formulas were identical (0.90). The intraclass correlation coefficients obtained with the Hadlock (0.84) and Campbell formulas (0.85) were lower. Conclusion: The validity of ultrasonic estimation of fetal weight at term with all four formulas was high.

A Comparison of Clinical and Ultrasonic Estimation of Fetal Weight

A Comparison of Clinical and Ultrasonic Estimation of Fetal Weight

A Comparison of Clinical and Ultrasonic Estimation of Fetal Weight

Objective: To compare the accuracy of routine ultrasonic and clinical birth weight estimation. Methods: The study sample included 1717 women with singleton pregnancies, admitted in early labor with an ultrasonic estimated fetal weight (EFW) performed during the preceding week. Clinical EFW was obtained before rupture of the membranes by the attending senior resident, who was unaware of the ultrasonic EFW. Accuracy was determined by the percentage error, the absolute percentage error, and the proportion of estimates within 10% of the actual birth weight (birth weight ± 10%). Statistical analysis was done by the paired t test, the comparison of correlated variances, the Wilcoxon sign test, and the χ 2 test. Actual birth weight in the study sample averaged 3334 ± 607 g (± standard deviation, [SD]) and ranged between 690 and 5320 g. Results: The means of all error terms of the clinical EFW were significantly smaller than those of the ultrasonic EFW. However, the rates of estimates within 10% of birth weight were not significantly different (72 and 69%, respectively). In birth weights less than 2500 g, both methods overestimated the birth weight, but the mean errors of the ultrasonic EFW were significantly smaller than those of the clinical EFW. The ultrasonic EFW had significantly higher rates of birth weight ± 10% than the clinical EFW (63 compared to 49%, respectively). In the 2500–4000 g birth weight, only the clinical EFW had no systematic error, whereas the ultrasonic EFW underestimated the birth weight. The mean errors of the clinical EFW were significantly smaller and the rate of birth weight ± 10% significantly higher than those of the ultrasonic EFW. In the birth weight greater than 4000 g, both methods underestimated the birth weight, and the mean errors and the rate of estimates within 10% of birth weight were similar for both methods. Conclusion: Clinical estimation of birth weight in early labor is as accurate as routine ultrasonic estimation obtained in the preceding week. In the lower range of birth weight (less than 2500 g), ultrasonic estimation is more accurate; in the 2500–4000 g range, clinical estimation is more accurate. In the higher range of birth weight (greater than 4000 g), both methods have similar accuracy.

Induction of labor versus expectant management in macrosomia: A randomized study

Macrosomia at term is associated with increased maternal and neonatal morbidity, including a higher rate of cesarean delivery and shoulder dystocia. Induction of labor has been suggested as a means to prevent further weight gain and improve outcome. The aim of this study was to determine whether or not induction of labor in these cases improves maternal and neonatal outcome. Patients at term with an ultrasonic fetal weight estimation of 4000-4500 g were prospectively randomized into two groups: induction of labor (group D and expectant management (group II). Patients with diabetes, a previous cesarean delivery, or nonvertex presentation were excluded. Outcome variables included mode of delivery, arterial cord pH, presence of shoulder dystocia, brachial plexus injury, clavicular fracture, cephalohematoma, and intraventricular hemorrhage. Of 273 patients who were eligible for the study, 134 were randomized to group I and 139 to group II. Parity, gestational age, and fetal weight estimation were similar in the two groups. The neonates of group II patients were significantly heavier (4132.8 +/- 347.4 versus 4062.8 +/- 306.9 g; P = .024). The rate of cesarean delivery was 19.4% in group I and 21.6% in group II patients (not significant [NS]). Cord pH was similar in both groups. Shoulder dystocia was diagnosed in five group I and six group II patients (NS). None developed brachial plexus injury. There were two cases of mild, transient brachial plexus injury in group II patients without documented shoulder dystocia. Mild intraventricular hemorrhage was diagnosed in three of 44 group I and two of 31 group II neonates evaluated (NS). In this prospective, randomized study, induction of labor for suspected macrosomia at term did not decrease the rate of cesarean delivery or reduce neonatal morbidity. Ultrasonic estimation of fetal weight between 4000 and 4500 g should not be considered an indication for induction of labor.

Ultrasound Fetal Weight Estimation: Precision or Guess Work?

We compared the prediction of birth-weight based on factors shown by epidemiological studies to influence it with the performance of 2 clinical examples of ultrasonic fetal weight estimation reported in the literature. The standardized absolute error of the 2 examples of ultrasonic fetal weight estimation was similar to estimation by multiple regression of birth-weight on maternal age, parity, height and weight in 11,516 Chinese mothers. This severely limits the clinical utility of the estimation derived from these ultrasonic measurements.

Accuracy of Ultrasonic Fetal Weight Estimation and Detection of Small for Gestational Age Fetuses

One hundred and eight-six pregnant women were studied with ultrasound for clinical suspicion of poor fetal growth. Fetal weight was estimated using biparietal diameter and mean abdominal diameter with a special nomogram. The fetal femur length (FL) to abdominal circumference (AC) ratio was also calculated. The mean interval between the last ultrasound examination and delivery was 9 days (range, 0 to 14 days). Eighty-three women had their last ultrasonic examination 0 to 4 days (mean, 2 days) before delivery. In this group the arithmetic mean of weight estimation errors was -1 gm (SD, 159 gm). The signed mean percent error was +0.6% (SD, 6.6%). Neither systematic nor random errors were found between different growth percentile groups. When small for gestational age (SGA) was defined as birthweight below 2.5 percentile, the sensitivity, specificity, and positive predictive value of the weight estimations were 82%, 92%, and 84%, respectively, in 186 cases. Significant differences were found in FL to AC ratios between growth pattern groups but fetal weight estimation was found to be superior in the detection of SGA fetuses.

Ultrasound in obstetric decision making. How accurate are late ultrasound scans in gestational age and fetal weight assessment?

Gestational age determination based on obstetric dating criteria, early pregnancy ultrasound scans, Dubowitz examinations, and ultrasound scans performed shortly before delivery were reviewed for 69 preterm infants requiring neonatal intensive care. The last ultrasound scans underestimated gestational age by a median of 8 days, and by 2 weeks or more in 20 of the 69 cases, as opposed to best dating criteria. Ultrasonic fetal weight estimation was more accurate, but erred by more than 20% in 10% of cases. When obstetric decisions regarding preterm neonates must be made without prior information regarding gestational age, late ultrasound findings must be applied with extreme care.

Accurate ultrasonic estimation of fetal weight. Prospective analysis of new ultrasonic formulas.

Five new ultrasonic weight formulae incorporating head circumference, fetal femur length, and a correction for oligohydramnios were prospectively analyzed in a group of 198 unselected patients scanned within 72 hours of birth. Comparison with the Shepard formula showed that inclusion of these parameters slightly, but significantly, improved the random error of weight estimation. The best-fit formula was: Log(10) BW = .04355HC + .05394AC - .0008582HC X AC + 1.2594 (FL/AC) - 2.0661.

Accurate ultrasonic estimation of fetal weight. Effect of head shape, growth patterns, and amniotic fluid volume.

Four hundred sixty-four fetuses underwent real time ultrasound examination within 72 hours before birth to evaluate other factors than the weight formula itself that might influence the accuracy of ultrasound weight estimation. The results indicated that fetal sex had no effect on weight estimation accuracy, but that fetal growth patterns, cephalic index, and the amount of amniotic fluid did. The weights of small-for-gestational age infants were significantly overestimated. Infants with oligohydramnios and low cephalic indexes were significantly underestimated by the ultrasonic weight formula. The weights of infants with high cephalic indexes were slightly overestimated and infants that were large-for-gestational age were slightly underestimated.