Amniotic fluid index and estimated fetal weight for prediction of fetal macrosomia: a prospective observational study

Objective: The purpose of this study was to assess the value of combining the estimated fetal weight (EFW) and amniotic fluid index (AFI) measured in term patients early in labor with intact membranes for prediction of macrosomia.

Methods: In a single center, prospective observational study, 600 patients in the first stage of labor before rupture of membranes in whom ultrasonography was performed to measure AFI and EFW, and these data were analyzed statistically to evaluate prediction of fetal macrosomia.

Results: Macrosomia occurred in 64 cases (10.6%). The AFI was significantly higher in the macrosomic group (p?=?0.001). It was noted that the area under receiver operating characteristic (ROC) curves for EFW was 0.93 and that of AFI was 0.67. Based on suggested combined EFW and AFI cutoffs of 4000?g and 164?mm, respectively, the positive predictive value (PPV) for combined parameters (92.3%) was higher than that of EFW (75%) and that of AFI (27%) and the likelihood ratio for combination (93.7%) was higher than that of EFW (24.7%) and that of AFI (21%).

Conclusion: Combined use of EFW and AFI improves prediction of macrosomia at birth rather than the EFW alone.     

Can a single preterm ultrasound accurately predict birth weight in gestational diabetes?

Objective: To evaluate the accuracy of the gestation-adjusted projection method of birth weight prediction, as compared to near delivery ultrasound estimated fetal weight, in a gestational diabetic population.

Methods: A retrospective cohort was conducted including all women with gestational diabetes who had an ultrasound estimated fetal weight (EFW) between 34^0/7 and 36^6/7 weeks and an additional ultrasound EFW within 7?d of delivery at term. The gestation-adjusted projection (GAP) method was applied to the earlier sonogram, resulting in the GAP predicted birth weight. The GAP predicted weight and the term ultrasound EFW were compared to the actual birth weight. Absolute and percent birth weight errors were compared using paired t-tests.

Results: The mean absolute percent errors and mean absolute errors for the GAP method and term ultrasound were 7.7?±?5.6% versus 7.1?±?5.1% and 256?±?184?g versus 236?±?169?g respectively (p?=?0.22 and p?=?0.29). The sensitivity of predicting birth weight ≥4000?g was 22% for the GAP method and 28% for term ultrasound, with specificity reaching 97% for both the methods.

Conclusion: The GAP method is as accurate as term ultrasound in predicting birth weight in gestational diabetes.     

Improving customized fetal biometry by longitudinal modelling

Objective: To develop customized biometric charts to better define abnormal fetal growth.

Methods: A total of 1056 singleton fetuses from the Raine Study underwent serial ultrasound biometry (abdominal circumference [AC], head circumference, and femur length) at 18, 24, 28, 34, and 38 weeks’ gestation. Customized biometry trajectories were developed adjusting for epidemiological influences upon fetal biometry using covariates available at 18 weeks gestation. Prediction accuracy (areas under the receiver operating characteristic curve [AUC] and 95% confidence interval [95%CI]) was evaluated by repeated random sub-sampling cross-validation methodology.

Results: The model for derived estimated fetal weight (EFW) performed well for EFW less than 10th predicted percentile (AUC?=?0.695, 95%CI, 0.692–0.699) and EFW greater than 90th predicted percentile (AUC?=?0.705, 95%CI, 0.702–0.708). Fetal AC was also well predicted for growth restriction (AUC?=?0.789, 95%CI, 0.784–0.794) and macrosomia (AUC?=?0.796, 95%CI, 0.793–0.799). Population-derived, sex-specific charts misclassified 7.9% of small fetuses and 10.7% of large fetuses as normal. Conversely, 9.2% of those classified as abnormally grown by population-derived charts were considered normal by customized charts, potentially leading to complications of unnecessary intervention.

Conclusions: Customized fetal biometric charts may offer improved ability for clinicians to detect deviations from optimal fetal growth and influence pregnancy management.     

The association between second trimester estimated fetal weight and small for gestational age at birth

Objective: To analyze diagnostic accuracy of second trimester ultrasound fetal growth parameters as predictors of small for gestational age (SGA) birth weight.

Methods: We reviewed the fetal biometry from 714 consecutive patients with second trimester ultrasounds. The estimated fetal weight (EFW) and abdominal circumference (AC) percentiles were tested as predictors of SGA at birth (<10‰).

Results: 87 (12.2%) patients had an SGA baby. Patients with a second trimester EFW?≤25‰ were significantly more likely to have SGA at birth (24.2% versus 10.3%, p?<?0.001). Similar results were seen for women with second trimester AC?≤25‰ (likelihood of SGA 21.9% versus 11.2%, p?=?0.013). A second trimester EFW?≤25‰ was a better predictor of SGA at birth than a second trimester EFW?≤?10‰ (Positive likelihood ratio 2.30 versus 2.09). In the second trimester, only 9 (1.3%) patients had an EFW 0–10‰, only 43 (6%) patients had an EFW 11–20‰, and only 46 (6.4%) patients had an EFW 91–99‰. Each other EFW centile had more than 10% of the patients.

Conclusions: The incidence of second trimester EFW or AC?≤10‰ is less common than expected from standard tables. An EFW?≤25‰ and an AC?≤25‰ should be considered the second trimester marker for risk of SGA at birth. However, due to the low likelihood ratio of, it is not clear if second trimester ultrasound should be used as a predictor of SGA at birth.     

Accuracy of fetal weight estimation by ultrasound in periviable deliveries

Abstract

Objective: To evaluate the accuracy of ultrasound estimated fetal weight (EFW) near viability, and to determine the adequacy of use of EFW in place of birth weight (BWT) for predicting prognosis for infants born near the limit of viability.

Methods: Retrospective chart review of women delivering between 22^0/7 and 25^6/7 weeks gestation (GA) with ultrasound performed within 7 days of delivery. Potentially relevant clinical factors were evaluated regarding their impact on accuracy of EFW. Estimated survival based on BWT and EFW, using an National Institute for Child Health and Human Development (NICHD) algorithm, were compared.

Results: Study included 93 infants. Mean absolute percent difference (accuracy) of EFW for BWT was 9.4% (95%CI 7.4–11.3). There was no correlation between EFW accuracy and BWT, GA, maternal age, or BMI. There was a 3% overestimation of BWT per 100?g decrease in BWT (p?=?0.001). Race, oligohydramnios, parity, smoking, or previous cesarean did not impact EFW accuracy. Mean predicted survival by the NICHD algorithm was 43.1% using BWT; 43.6% using EFW (p?=?0.63). An overestimation of predicted survival (using EFW instead of BWT) greater than 20% was detected in only two cases.

Conclusion: Accuracy is similar to prior studies. Estimated newborn survival based on EFW is similar to that based on BWT.     

Defining fetal growth restriction: abdominal circumference as an alternative criterion

Purpose: The purpose of this study is to determine if using abdominal circumference percentile (AC) to define fetal growth restriction (FGR) improves ultrasound at ≥36 weeks as a screening test for small for gestational age (SGA).

Materials and methods: All non-anomalous singletons undergoing ultrasound at a single center at ≥36 weeks during 12/2008–5/2014 were included. FGR was defined as (estimated fetal weight) estimated fetal weight (EFW) and/or abdominal circumference (AC)?Results: There were 1594 ultrasounds. Median (IQR) ultrasound GA was 37.3 (36.6–38.0), days to delivery 10.6 (5.0–18.4), and delivery GA 39.29 (38.6–39.9). EFW <10 had the following characteristics: sensitivity 50.6%, FPR 2.0%, PPV 83.8%, and AUC 0.743. Using AC <10, these were 64.0, 2.9, 81.3, and 0.806, respectively. Using AC or EFW <10, these were 67.5, 3.3, 80.3, and 0.821, respectively; this criterion has the largest AUC (p?Conclusions: AC <10 is more sensitive and has a similar PPV compared with EFW <10 for SGA. Using AC <10 or EFW <10 has the best balance of sensitivity and specificity as a screening test and has a low FPR. AC may be a reasonable alternative criterion to EFW for FGR diagnosis.     

The influence of fetal sex on the antenatal diagnosis of small for gestational age

Objective: We evaluated the influence of fetal sex on the antenatal diagnosis and detection of small for gestational age (SGA).

Methods: The cohort consisted of unselected singleton pregnancies, undergoing routine biometry and cerebroplacental ratio (CPR) assessment at 36 weeks. Locally fitted equations for centiles and Z scores were used. “Ultrasound SGA” was defined as estimated fetal weight (EFW)?Results: Among 4112 pregnancies, there were 235 female “ultrasound SGA” fetuses and 177 male; (odds ratios (OR) 1.502 (1.223???1.845)); the detection rate of SGA at birth was 50.6% and 40.9%, respectively (OR 1.479 (0.980???2.228)). In “ultrasound SGA” girls the abdominal circumference growth velocity (ACGV) between 20 and 36 weeks was less frequently in the lowest decile (OR 0.490 (0.320???0.750)), with no differences in CPR.

Conclusions: Females are more commonly diagnosed as SGA; those diagnosed may be at less risk than males.     

Added value of cerebro-placental ratio and uterine artery Doppler at routine third trimester screening as a predictor of SGA and FGR in non-selected pregnancies

Objectives: The objective of this study is to determine the added value of cerebroplacental ratio (CPR) and uterine Doppler velocimetry at third trimester scan in an unselected obstetric population to predict smallness and growth restriction.

Methods: We constructed a prospective cohort study of women with singleton pregnancies attended for routine third trimester screening (32⁺⁰–34⁺⁶ weeks). Fetal biometry and fetal–maternal Doppler ultrasound examinations were performed by certified sonographers. The CPR was calculated as a ratio of the middle cerebral artery to the umbilical artery pulsatility indices. Both attending professionals and patients were blinded to the results, except in cases of estimated fetal weight Results: A total of 1030 pregnancies were included. The mean gestational age at scan was 33 weeks (SD 0.6). The addition of CPR and uterine Doppler to maternal characteristics plus EFW improved the explained uncertainty of the predicting models for SGA (15 versus 10%, p?p?=?.03). However, the addition of CPR and uterine Doppler to maternal characteristics plus EFW only marginally improved the detection rates for SGA (38 versus 34% for a 10% of false positives) and did not change the predictive performance for FGR.

Conclusions: The added value of CPR and uterine Doppler at 33 weeks of gestation for detecting defective growth is poor.     

Fetal biacromial diameter as a new ultrasound measure for prediction of macrosomia in term pregnancy: a prospective observational study

Objective: The current study aims to evaluate a simple method for sonographic measurement of the fetal biacromial diameter for prediction of fetal macrosomia in term pregnancy.

Materials and methods: The current study was a single center prospective observational study conducted in a tertiary University Hospital from January 2015 to May 2017. We included all consecutive term (37–42 weeks) pregnant women presented to the labor ward for delivery. Ultrasound parameters were measured as biparietal diameter, head circumference, transverse thoracic diameter, mid arm diameter, abdominal circumference, femur length, estimated fetal weight, and amniotic fluid index. The proposed ultrasound formula “Youssef’s formula” to measure the fetal biacromial diameter is: [Transverse thoracic diameter +2?×?midarm diameter]. The accuracy of proposed formula was compared to the actual biacromial diameter of the newborn after delivery. The primary outcome of the study was accuracy of sonographic measurement of fetal biacromial diameter in prediction of fetal macrosomia in terms of sensitivity and specificity

Results: The study included 600 participants; 49 (8.2%) of them delivered a macrosomic neonates and 551 (91.8%) delivered average weight neonates. There was no statistical significant difference between the proposed fetal biacromial diameter measured by ultrasound and the actual neonatal biacromial diameter measured after birth (p?=?.192). The area under the curve (AUC) for prediction of macrosomia at birth based on the fetal biacromial diameter and the abdominal circumference was 0.987 and 0.989, respectively, on receiver operating characteristic (ROC) curve analysis. Using the biacromial diameter cutoff of 15.4?cm has a PPV for prediction of macrosomia (88.4%) and 96.4% sensitivity with overall accuracy of 97%. Similarly, with the abdominal circumference (AC) cutoff of 35.5?cm, the PPV for prediction of macrosomia (87.7%) and 96.4% sensitivity with overall accuracy of 96.83%. No statistical significant difference between both of them was observed for prediction of fetal macrosomia (p?=?.841)

Conclusions: The sonographic measurement of fetal biacromial diameter seems to be a new simple and accurate method for prediction of fetal macrosomia and shoulder dystocia at birth.     

Divergence of estimated fetal weight and birth weight in singleton fetuses

Objective: To evaluate differences in distribution of estimated fetal weight (EFW) and birth weight (BW) of ongoing fetuses and neonates of the same gestational age.

Methods: Reference curves for EFW (Hadlock BPD-HC-AC-FL formula, N?=?1191) and BW (N?=?1036) in singleton pregnancies from 24⁺⁰ to 40⁺⁶ gestational weeks were calculated. Multiple pregnancies, fetuses with major or multiple abnormalities or syndromes and iatrogenic preterm deliveries due to preeclampsia or abnormal fetal Doppler were excluded. The standardized residuals for EFW and BW were calculated and compared.

Results: EFW and BW can be accurately described by quadratic equations (R²?=?0.944 and 0.807, respectively). The distribution of standardized residuals for BW using the EFW formula was negative from 28⁺⁰ to 35⁺⁶ weeks. The 50th and 5th centiles of BW were lower than those of EFW throughout prematurity, and they converged at approximately 38 gestational weeks. The 5th centile for BW was 30% lower than the 5th centile for EFW at 27 weeks, 27.5% lower at 30 weeks and 19.4% at 34 weeks.

Conclusions: Preterm infants have lower BW distribution compared to the expected EFW of ongoing pregnancies of the same gestational age, supporting the concept of hidden intrauterine morbidity for a proportion of these infants.     

Specific formulas improve the estimation of fetal weight by ultrasound scan

Abstract

Objective: To develop and evaluate local, sex specific, small for gestational age (SGA) specific, large for gestational age (LGA) specific and combined (biometry, sex and Doppler indices) formulas for ultrasound estimated fetal weight (EFW).

Method: Low-risk singleton pregnancies that delivered within 7 days from ultrasound examination were assessed. A formula-generating group (1407 pregnancies) and a validation group (469 pregnancies) were created. Fractional regression analysis was used to develop the formulas. Systematic error, random error, fraction within the 10% of actual birth weight and Bland–Altman analysis were used.

Results: The local formula and the Hadlock formula with local co-efficients performed better than the Hadlock formula. The SGA-specific formula, the LGA-specific formula and the combined formula had the lower systematic error (MSE: +0.0022291, ?0.4226888, +0.8386222, respectively) and the narrower 95% LOA (?292.8 to +292.23, ?485.6 to +461.5, ?425.7 to +450.46, respectively). The SGA- and the LGA-specific formulas had higher fraction within the 10% of actual birth weight (81.5% and 84%, respectively).

Conclusions: Local formulas improve the EFW calculation. The combined formula can further optimize the accuracy and precision. Application of specific formulas for the small and the large fetus had the most pronounced effect in improving fetal weight estimation.     

Is the fetal cerebroplacental ratio better that the estimated fetal weight in predicting adverse perinatal outcomes in a low risk cohort?

Objective: In high-risk pregnancies combining the cerebro–placental ratio (CPR) with the estimated fetal weight (EFW) improves the identification of vulnerable fetuses. The purpose of this study was to assess the CPR and EFW’s ability to predict adverse obstetric and perinatal outcomes in a low-risk pregnancy, when measured late in gestation.

Methods: This was a retrospective study of women who birthed at Mater Mothers Hospitals, Brisbane, Australia between 2010 and 2015. We included all nonanomalous singleton pregnancies that had an ultrasound scan performed between 36 and 38 weeks gestation. Excluded was any major congenital abnormality, aneuploidy, multiple pregnancy, preterm birth, maternal hypertension, or diabetes. The primary outcome was a severe composite neonatal outcome (SCNO) defined as severe acidosis (umbilical cord artery pH <7.0, cord lactate ≥6?mmol/L, cord base excess ≤-12?mmol/L) Apgar score ≤3 at 5 minutes, admission to the neonatal intensive care unit (NICU), and death. A low CPR was defined as <10th centile for gestation and small for gestational age (SGA) was defined as an EFW <10th centile and appropriate for gestational age (AGA) was defined as EFW ≥10th centile.

Results: Of 2425 pregnancies, 13.2% (321/2425) had a fetus with a CPR <10th centile and 13.7% (332/2425) with an EFW <10th centile. Both a low CPR and SGA predicted the SCNO. Individually a low CPR and SGA had sensitivity for detection of SCNO of 23.3% and 24.7%, respectively which increased to 36.7% when combined. Both were associated with emergency caesarean for nonreassuring fetal status (NRFS), as well as early-term birth and admission to NICU. Stratifying the population into EFW <10th centile and EFW ≥10th centile, a low CPR maintained its association with the SCNO, early-term birth and emergency caesarean for NRFS in the cohort with an EFW <10th centile but SCNO lost its association with a low CPR in the EFW >10th cohort. Stratifying the population into CPR <10th centile and CPR >10th centile, a low EFW was associated with early-term birth, induction of labor, admission to NICU, and the SCNO.

Conclusions: In a low-risk cohort both the CPR and EFW individually and in combination predicts adverse obstetric and perinatal outcomes when measured late in pregnancy. However, the predictive value was enhanced when both were used in combination.     

超声测量胎儿腹围预测新生儿出生体重的研究

目的探讨超声测量胎儿腹围在预测新生儿出生体重和诊断巨大儿中的价值。方法在孕妇分娩前1周超声测量胎儿腹围,追踪胎儿的出生体重,分析胎儿腹围与出生体重的关系。结果(1)共检测1475例单胎孕妇胎儿,胎儿腹围与出生体重呈直线正相关关系,r为0.85(P<0.01)。(2)胎儿腹围<34cm者中无一例巨大儿;胎儿腹围<35cm有1007例,99.7%的新生儿平均出生体重<4000g;胎儿腹围在35～35.9cm有206例,新生儿平均出生体重为(3691±277)g,其中14.6%(30例)的新生儿出生体重≥4000g;胎儿腹围在36～36.9cm有149例,其中51.0%(76例)的新生儿出生体重≥4000g,新生儿平均出生体重为(3957±256)g;胎儿腹围在37～37.9cm有64例,其中84.4%(54例)的新生儿出生体重≥4000g,平均出生体重(4205±250)g;胎儿腹围≥38cm有44例,新生儿平均出生体重≥4000g者为100%(44例),平均出生体重为(4489±267)g。(3)1475例中有811例孕妇行剖宫产术(55.0%),新生儿出生体重为4000～4500g者,剖宫产率为71.4%(125/175),出生体重≥4500g者,剖宫产率为93.8%(30/32),均显著高于新生儿出生体重<4000g的剖宫产率(P<0.01)。结论超声测量胎儿腹围可以预测新生儿出生体重。胎儿腹围与胎儿体重呈高度直线正相关。胎儿腹围<35cm提示发生巨大儿的可能性极低;≥37cm提示巨大儿的可能性大。     

Five-dimensional long bones biometry for estimation of femur length and fetal weight at term compared to two-dimensional ultrasound: a pilot study

Background/objective: This study aimed to evaluate accuracy of five-dimensional long bones (5D LB) compared to two-dimensional ultrasound (2DUS) biometry to predict fetal weight among normal term women.

Methods: Fifty six normal term women were recruited at Ain Shams Maternity Hospital, Egypt from 14 May to 30 November 2015. Fetal weight was estimated by Hadlock’s IV formula using 2DUS and 5D LB. Estimated fetal weights (EFW) by 2DUS and 5D LB were compared with actual birth weights (ABW).

Results: Mean femur length (FL) was 7.07?±?0.73?cm and 6.74?±?0.67?cm by 2DUS and 5D LB (p?=?.02). EFW was 3309.86?±?463.06?g by 2DUS and 3205.46?±?447.85?g by 5D LB (p?=?.25). No statistical difference was observed between ABW and EFW by 2DUS (p?=?.7) or 5D LB (p?=?.45). Positive correlation was found between EFW by 2DUS, 5D LB, and ABW (r?=?0.67 and 0.7; p?p?=?.15).

Conclusions: 2DUS and 5D LB had same accuracy for fetal weight estimation at normal term pregnancy.     

Macrosomia prediction using ultrasound fetal abdominal circumference of 35 centimeters or more

OBJECTIVE: To determine if birth weights greater than 4000 g can be predicted by ultrasound measurements of abdominal circumferences. METHODS: In 1996, 254 newborns delivered at Tampa General Hospital weighed at least 4000 g, 84 of whom had ultrasound examinations within 2 weeks of delivery. Those were compared with 84 neonates with recent ultrasounds who weighed less than 4000 g. Data were abstracted retrospectively from maternal medical records. RESULTS: The best linear predictor of birth weight was ultrasound measurement of abdominal circumference (AC), which had a correlation coefficient of 0.95. An AC measurement of 35 cm or more predicted 93% of macrosomic infants. Among 177 macrosomic infants born vaginally, 23 (13%) had shoulder dystocia. In that group, induction of labor was associated with a greater than three-fold increase in risk of shoulder dystocia (odds ratio [OR] 3.4, 95% confidence interval [CI] 1.4, 8.2; P < .01). Labor augmentation was not associated with increased risk of shoulder dystocia. CONCLUSION: Abdominal circumference measurements were useful in screening for suspected macrosomia. An AC measurement of 35 cm or more identified more than 90% of macrosomic infants who were at risk for shoulder dystocia. Induction of labor in macrosomic patients increased the risk of shoulder dystocia.     

Third trimester ultrasound accuracy and delivery outcome in obese and morbid obese pregnant women

Objective: Several studies have highlighted the negative impact of maternal obesity on ultrasound accuracy for fetal weight estimation (EFW). However, the evidence is conflicting. We aimed in our study to find if the ultrasound accuracy for EFW would differ or decrease in obese and morbid obesity classes. We also studied the mode of delivery within the same cohort.

Methods: It is a retrospective study of obese patients with recorded BMI ≥30?kg/m², class I and II (BMI: 30–39.9?kg/m²) compared with extreme obese class III (BMI ≥40?kg/m²), who gave birth after 28-week gestation of viable singleton, who had an ultrasound within 7 d of delivery with reported normal amniotic fluid and no major fetal anomaly; the EFW was consistently measured through Hadlock regression formula in the period of 2014–2015 inclusive. Differences between the EFW and actual birth weight (ABW) were assessed by percentage error, accuracy in predictions within ±10% of error and the Pearson correlation coefficient were used to correlate EFW with the ABW. The study’s secondary outcome was to study the mode of delivery and the rate of cesarean section in obese and morbid obese patients.

Results: Total 106 cases fulfilled our criteria. Class I and II as the first group (n?=?53). Class III as the second group (n?=?53). Maternal and birth characteristics were similar. The Pearson correlation coefficient equal 1 in both groups. The overall mean absolute difference (MAD) in grams of the whole obese cohort was 242?±?213. The MAD was 242?±?202 and 242?±?226?g for the first and second group, respectively (p?=?1.0). The overall mean absolute percentage error (MAPE) in this obese cohort was 8%. The MAPE for the first and second group, respectively were 8 and 7% (p?=?0.4). The overall rate of cesarean delivery was 60% (64/106) with no differences between the obese and morbid obese BMI classes. Sixty-six percentage (42/64) of these cesarean cases was for repeat cesarean section.

Conclusion: Despite what has been previously reported about the negative impact of maternal obesity on EFW accuracy, we could not demonstrate this relationship in our obese cohort (MAPE <10%). In addition, we could not illustrate a significant difference in ultrasound accuracy across various obesity classes. However, we found a significantly increased rate of delivery by repeated cesarean section in this obese cohort.     

A scoring system for detection of macrosomia and prediction of shoulder dystocia: A disappointment

Objective. To develop a scoring system for the detection of a macrosomic fetus (birth weight (BW) ≥ 4000 g) and predict shoulder dystocia among large for gestational age fetuses.

Study design. We retrospectively identified all singletons with accurate gestational age (GA) that were large for GA (abdominal circumference (AC) or estimated fetal weight (EFW) ≥ 90% for GA) at ≥37 weeks with delivery within three weeks. The scoring system was: 2 points for biparietal diameter, head circumference, AC, or femur length ≥90% for GA, or if the amniotic fluid index (AFI) was ≥24 cm; for biometric parameters <90% or with AFI <24 cm, 0 points. The predictive values for detection of shoulder dystocia were calculated.

Results. Of the 225 cohorts that met the inclusion criteria the rate of macrosomia was 39% and among vaginal deliveries (n = 120) shoulder dystocia occurred in 12% (15/120; 95% confidence interval (CI) 7–20%). The sensitivity of EFW ≥4500 g to identify a newborn with shoulder dystocia was 0% (95% CI 0–21%), positive predictive values 0% (95% CI 0–46%), and likelihood ratio of 0. For a macrosomia score >6, the corresponding values were 20% (4–48%), 25% (5–57%) and 2.3.

Conclusion. Though the scoring system can identify macrosomia, it offers no advantage over EFW. The scoring system and EFW are poor predictors of shoulder dystocia.     

Accuracy of sonographic estimation of fetal weight before induction of labor in diabetic pregnancies and pregnancies with suspected fetal macrosomia

AIMS: To evaluate the accuracy of sonographic estimation of fetal weight (EFW) in diabetic pregnancies and pregnancies with suspected fetal macrosomia. METHODS: 63 women with diabetic pregnancies, 74 nondiabetic women with suspected large-for-gestational-age (LGA) infants, and 161 controls underwent ultrasound assessment prior to induction of labor. EFW was compared to the weight at birth, 1-3 days later. RESULTS: EFW was highly correlated to birth weight. Absolute or actual weight differences between the birth weight and the EFW, and the rate of EFW within 10% of birth weight were not different between the groups. A linear regression model controlling for maternal and gestational age, diagnosis of gestational or pregestational diabetes, birth weight, gravidity, parity, nulliparity, placental location and AFI was not significantly correlated to the absolute or actual weight differences. In pregnancies with suspected LGA, higher birth weight was an independent and significant predictor of high weight difference inaccuracy. CONCLUSIONS: The ultrasonographic EFW 1-3 days before delivery is highly correlated with birth weight, reaffirming the clinical use of abdominal circumference and femur length in estimating fetal weight near labor at term. In pregnancies with suspected LGA fetuses and higher prevalence of macrosomia, ultrasound has higher sensitivity but lower specificity than the controls.     

Clinical and sonographic estimation of fetal weight performed during labor by residents

OBJECTIVE: This study was undertaken to assess the accuracy of both clinical and sonographic estimations of the fetal weight (EFW) performed during the active phase of labor by residents. METHODS: The study protocol consisted of achieving clinical, followed by sonographic EFW by the admitting resident during the active phase of labor. Patients who had an EFW (clinical or sonographic) within the last 2 weeks were excluded from the study. In addition, the effect of the following variables on the accuracy of the EFW were examined: maternal age, maternal weight and body mass index, parity, the Bishop score before obtaining the EFW, gestational age, birth weight, and the postgraduate year of the examiner. The Pearson correlation, chi2 test, and Student t test were the statistical analyses used. We also calculated the sensitivity, specificity, and positive and negative predictive values for clinical and sonographic EFW for detecting macrosomia (birth weight > or = 4000 g). RESULTS: A total of 192 patients participated in this study. The coefficient of correlation between the clinical and sonographic EFW and the actual birth weight was 0.59 (P < .0001) and 0.65 (P < .0001), respectively. Clinical EFW was correct (within +/-10%) in 72% of the cases and the sonographic EFW was correct (within +/-10%) in 74% of the cases. However, the sensitivity of predicting birth weight of 4 kg or more was only 50% for both clinical and sonographic EFW, with 95% and 97% specificity, respectively. None of the clinical variables that were tested were significantly associated with the accuracy of the EFW. CONCLUSION: Both clinical and sonographic EFW performed during the active phase of labor by residents correlate with the actual birth weight but have poor sensitivity in detecting macrosomic fetuses. Sonographic EFWs offer no advantage over clinical EFWs.     

Growth restriction: identifying fetuses at risk

Purpose: Examine risks of intrauterine growth restriction (IUGR) and composite perinatal outcomes with estimated fetal weights (EFW) 10–20th%, and compare outcomes using umbilical artery Doppler (UAD).

Materials and methods: Retrospective, cohort evaluating ultrasound (US) EFW 10–20th%, between 2002 and 2012. Cases were identified with EFW % 10–20. Controls, EFW?>20th% were obtained for each case, matched by gestational age, and US date. Unadjusted and adjusted logistic regression was used for outcomes.

Results: Seven hundred and sixty-seven cases met criteria with matched controls. Fetuses having EFW 10–20th% (GA 33.6?±?3.7 weeks) had increased IUGR on follow up ultrasound (OR 26.5[10.2–68.7], p?p?p?p?p?Conclusions: Pregnancies with EFW 10–20th% at the time of initial US are at increased risk for developing IUGR and being SGA at birth, with more NICU admissions and composite perinatal outcomes; abnormal UAD evaluation in cases conveyed further increase in outcomes.