Comparing Population-Based Fetal Growth Standards in a US Cohort

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.

Background: Fetal size is often dichotomized as normal or abnormal using the 10th percentile of estimated fetal weight (EFW) or abdominal circumference as a cutoff. While the risk of adverse perinatal outcomes decreases with increasing fetal weight percentile, no percentile completely eliminates that risk. Objective: The aim of this study was to compare perinatal outcomes between fetuses with an EFW between the 10th and 20th percentiles and those with an EFW between the 20th and 90th percentiles (i.e., >20 and <90) at the beginning of the accelerated growth stage (28.0–30.0 weeks’ gestation). Methods: We conducted a retrospective cohort study of singleton pregnancies managed at a quaternary center in Mexico City (2017–2024). Outcomes were compared based on EFW percentiles at 28.0–30.0 weeks. The primary outcome was adverse neonatal outcome (ANeO), defined as the presence of at least one of the following: umbilical artery pH ≤ 7.1, 5 min Apgar ≤ 7, NICU admission, early neonatal hypoglycemia, non-reassuring fetal status, respiratory distress syndrome, intraventricular hemorrhage, hypoxic–ischemic encephalopathy, or perinatal death. Secondary outcomes included progression to fetal growth restriction (FGR) and low birth weight. Modified Poisson regression was used to estimate adjusted risk ratios (aRRs) with 95% confidence intervals (CIs). Results: Among 650 cases, ANeO occurred in 45.8% of fetuses in the 10th–20th percentile group vs. 29.4% in the 20th–90th percentile group (aRR: 1.51, 95% CI: 1.22–1.86; p < 0.001). FGR and low birth weight were also more frequent in the 10th–20th percentile group (21.1% and 27.6% vs. 6.4% and 5.8%, respectively; p < 0.001). Conclusions: Fetuses between the 10th and 20th percentiles at 28–30 weeks have increased risks of neonatal morbidity, FGR, and low birth weight.

Objective: To evaluate the utility of a chromosomal microarray (CMA) in fetuses with isolated fetal growth restriction (FGR) and explore risk factors for the prediction of chromosomal aberration and perinatal adverse outcomes. Method: This study included 271 fetuses of estimated fetal weight less than the 3rd percentile without other structural malformation. Early-onset and late-onset FGR were defined as gestational weeks less than 32 weeks and more than 32 weeks respectively. These patients underwent quantitative fluorescent polymerase chain reaction (QF-PCR) and CMA as the first-line genetic detection strategy. Chromosomal anomalies were compared after stratified analysis by the early-onset and the late-onset FGR, including the absence or presence of ultrasound soft markers, abnormal amniotic fluid, abnormal umbilical Doppler, and gestational disorders. The follow-up time was within 1 year after birth. Logistic regression was used to seek risk predictors of chromosomal aberration and perinatal adverse outcomes for isolated FGR. Results: The CMA identified clinically significant variants in 18/271 (6.6%) fetuses, and variants of unknown significance (VOUS) in 15/271 (5.5%) fetuses. Stratified analysis showed that there was a higher incidence of clinically significant variants in fetuses with the early-onset FGR compared with late-onset FGR (8.7%, 17/195 vs. 1.3%, 1/76, p < 0.05). Regression analysis showed that early gestational age (GA) at diagnosis of FGR was the major risk factor for chromosomal aberration (OR = 0.846). By variable regression analysis, early GA at diagnosis and decreased estimated fetal weight (EFW) percentile of suspicion of FGR, asymmetrical FGR, abnormal amniotic fluid, and severe preeclampsia could all increase the risk of adverse outcomes of isolated FGR including intra-uterine fetal death (IUFD), termination of pregnancy (TOP), and preterm birth in pregnancies with FGR. Conclusion: This study emphasized the value of microarrays for unbalanced genomic variants in fetuses with isolated FGR, especially since the gestational age of nullipara was less than 32 weeks. Perinatal adverse outcomes of isolated FGR were influenced by multiple factors including GA and estimated fetal weight (EFW) percentile of suspicion of FGR, asymmetrical FGR, abnormal amniotic fluid, and severe preeclampsia.

Background: Accurate estimated fetal weight (EFW) is crucial in determining delivery management. Several methods to estimate fetal weight were used such as abdominal palpation, measurement of symphisis fundal height (SFH), and ultrasound examination. Risanto’s formula based on Indonesian population had been already proven to be more accurate than Johnson’s formula. The formula was as follows: Y = 125 X - 880 where Y was EFW in grams, X was SFH in cm, and 125 was the constanta.Objective: To compare the accuracy of Risanto’s formula and ultrasound examination in estimating fetal weight.Method: A cross sectional study was carried out in Sardjito hospital, Faculty of Medicine Universitas Gadjah Mada, from March 2013 to March 2014. A total of 400 pregnant women meeting the inclusion criteria at 37 – 42 weeks of gestation were recruited. The estimated fetal weight using Risanto’s formula (R_EFW) was compared to the estimated fetal weight using ultrasound measurement (U_EFW). The U_EFW was done by obstetricians on duty or senior residents using Hadlock’s formula. Actual birth weight (ABW) was measured using the same calibrated baby scale. Accuracy was determined by comparing the mean difference between the R_EFW minus ABW (ΔR_EFW) and the U_EFW minus ABW (ΔU_EFW). Paired t-test was used for statistical analysis.Result and Discussion: The mean ABW was 3025.3 ± 414.6 gram and the mean R_EFW was 2972.7 ± 365.4 grams, while the mean U_EFW was 3058.7 ± 423.2 grams. The mean ΔR_EFW was lower than the mean ΔU_EFW (178.2 ± 147.6 grams vs 197.5 ± 155.4 grams; 95% CI 1.24 – 36.68; p = 0.04).Conclusion: Risanto’s formula was more accurate than ultrasound measurement in estimating fetal weight.Keywords: Estimated fetal weight, Risanto’s formula, Ultrasonography, Fundal height

Intrauterine growth restriction is associated with persistent aortic wall thickening and glomerular proteinuria during infancy

ABSTRACTObjectiveTo identify foetal growth restriction (FGR) based on estimated foetal weight (EFW) &lt; 10th percentile, abdominal circumference (AC) &lt; 10th percentile or both EFW and AC &lt; 10th percentile. To determine which group(s) is associated with a higher risk for adverse neonatal outcomes in singleton FGR pregnancies.Study DesignRetrospective cohort study of singleton deliveries with prenatal FGR diagnosis at a single tertiary hospital system 1/1/2021–12/31/2021. FGR was defined as: EFW &lt; 10th percentile only (EFW group), AC &lt; 10th percentile only (AC group), or both EFW/AC &lt; 10th percentile at initial diagnosis (EFW/AC group). The primary composite neonatal outcome includes urgent caesarean section delivery, APGAR &lt; 6 at 1 or 5 min, NICU admission, stillbirth, or neonatal death.ResultsA total of 647 patients met inclusion criteria (EFW: 168, AC: 139, EFW/AC: 340) and no differences were observed in maternal demographics between groups. The composite neonatal outcome occurred at a higher frequency in EFW (36.3%) and EFW/AC (37.8%) groups compared to AC group alone (22.3%) (p = 0.004). Gestational age at delivery in days was earlier in EFW/AC group (264 [258, 273]) compared to EFW (267 [259, 273]) and AC (269 [264, 274]) groups (p &lt; 0.001). Although not reaching statistical significance, there was higher rate of preeclampsia with severe features in the EFW/AC group (20%) compared to the EFW (13.1%) or AC groups (13.7%) (p = 0.078).ConclusionsEFW and EFW/AC groups were associated with a higher risk of adverse neonatal outcomes compared to the AC group. Delivery occurred earlier in pregnancies diagnosed with FGR based on EFW and EFW/AC compared to the AC group. These findings can inform risk counselling in pregnancies diagnosed with FGR.

Diagnosis and management of fetal growth restriction: the ISUOG guideline and comparison with the SMFM guideline.

A conditional standard for the customized fetal growth trajectory in twin pregnancy

This study aimed to evaluate if an estimated fetal weight (EFW) between 10 and 15th percentiles at the time of anatomy ultrasound, referred to as borderline fetal growth, is associated with progression to fetal growth restriction (FGR) on subsequent ultrasound, delivery of a small for gestational age (SGA) neonate, or neonatal intensive care (NICU) admission.We performed a secondary analysis using the Nulliparous Pregnancy Outcomes Study: Monitoring Mothers-to-be (nuMom2b) data. The exposures were normotensive pregnancies with non-anomalous singleton gestations with normal growth, defined as EFW >15th percentile at the anatomy scan compared to borderline fetal growth fetuses defined as those with an EFW in the 10 to 15th percentiles. The primary outcome was FGR at subsequent ultrasound, defined as EFW or AC <10%. The secondary outcomes were NICU admission and SGA neonate. Univariable analyses were performed comparing maternal baseline demographic and clinical characteristics. Multivariable analysis was performed for the primary outcome with variables adjusted a priori for body mass index, smoking status, race/ethnicity, insurance status, and drug use.In total, 4,883 patients met inclusion criteria with 114 in the borderline fetal growth group and 4,769 in the normal growth group. There were no significant differences in maternal demographic or medical characteristics. In adjusted multivariable analysis, patients with borderline growth had significantly higher odds of being diagnosed with FGR at their subsequent scan (adjusted odds ratio [aOR] = 6.68, confidence interval [CI]: 3.98-11.20) compared to those with normal growth. For secondary outcomes, patients with borderline fetal growth were significantly more likely to have SGA neonates (6.14 vs. 2.67%, p = 0.025). There was no difference in admissions to the NICU between groups.Diagnosis of borderline fetal growth at the time of the anatomy scan was associated with significantly increased odds of progression to FGR at subsequent scans and delivery of an SGA neonate. · Patients with EFWs between the 10th and 15th percentiles, referred to as borderline fetal growth, are at an increased risk of progression to FGR compared to those with EFWs >15th percentile.. · Patients with borderline fetal growth are more likely to deliver SGA neonates compared to those with EFWs >15th percentile.. · Providers should consider follow-up antenatal growth assessment in patients with borderline fetal growth..

Objective. Approximately half of small for gestational age (SGA) cases are due to maternal or fetal pathology, and may result in significant neonatal morbidity and mortality. The estimated fetal weight (EFW) measurement is the cornerstone of ultrasonographic findings when diagnosing and managing SGA pregnancies. Our objective was to determine the ultrasound accuracy of EFW in SGA pregnancies.Methods. A retrospective chart review was performed of all pregnancies complicated by SGA from a single institution (Stanford University) over a 2-year-period (2004–2006). SGA was defined as EFW ≤ 10%. 98 neonates whose last ultrasound for EFW occurred within 7 days of delivery were included in the study. The absolute differences between the EFW and birthweight (BW) were analyzed, and the absolute percent errors were calculated as (EFW − BW)/BW × 100. The mean absolute differences and mean absolute percent errors were analyzed across all gestational ages (GA) and EFWs using one-way analysis of variance.Results. The mean absolute percent error for the entire cohort was 8.7% (±6.3%). There was no statistically significant difference in the mean absolute percent error across all GAs (<32 weeks, 32–36 weeks, >36 weeks), and EFWs (<1500 g, 1500–2000 g, >2000 g).Conclusion. Ultrasound measurement of EFW in SGA pregnancies is consistent across all GAs and EFW measurements.

Estimated fetal weight (EFW) is an important metric at delivery as neonates with abnormal birthweight and their mothers are at higher risk of birth complications. Data regarding optimal EFW assessment in gravidas with obesity is inconsistent, and with the increasing incidence of obesity, clarification of this question is crucial. We aimed to compare accuracy of ultrasound (US)-derived EFW and clinical assessments of EFW in predicting neonatal birthweight among gravidas with obesity. This prospective cohort study enrolled gravidas with obesity and a singleton pregnancy admitted for delivery at term. EFW was determined using either US biometry or clinical assessment (Leopold's maneuvers, Johnson's formula, and Insler's formula) at time of admission. Our primary outcome was accurate EFW, defined as EFW within 500 g of birthweight. Secondary outcomes included ability to predict small-for-gestational age (SGA) and large-for-gestational age (LGA) birthweights. These outcomes were compared between all EFW methods. A total of 250 gravidas with a median body mass index of 36.4 kg/m2 were enrolled. Admission US outperformed Leopold's maneuvers in obtaining accurate EFW (81.6% versus 74.5%, P = .03). When comparing all methods, Johnson's and Insler's formulae performed the worst, accurately predicting EFW in only 27.4% and 14.3% of cases, respectively. Likewise, US-derived EFW outperformed Leopold's maneuvers and fundal height in the prediction of SGA and LGA neonates. US is more accurate than clinical assessment of EFW in gravidas with obesity both for estimation of actual birthweight and prediction of abnormal birthweight. Universal late third-trimester or peripartum US for EFW should be considered in gravidas with obesity.

Background Accurate assessment of fetal size is essential in providing optimal prenatal care. National Institute of Child Health and Human Development (NICHD) study from 2015 demonstrated that estimated fetal weight (EFW) differed significantly by race/ethnicity after 20 weeks. There is a large Somali population residing in Minnesota, many of whom are cared for at our maternal fetal medicine practice at the University of Minnesota. Anecdotally, we noticed an increased proportion of small-for-gestational age diagnoses within this population. We sought to use our ultrasound data to create a reference standard specific for this population and compare to currently applied references. Purpose We aimed to model fetal growth standards within a healthy Somali population between 16 and 40 weeks gestation, and address possible differences in the growth patterns compared with standards for non-Hispanic White, non-Hispanic Black, Hispanic, and Asian singleton fetuses published by the NICHD in the Fetal Growth Study. Materials and methods This is a retrospective cohort study using ultrasound data from 527 low risk pregnancies of Somali ethnicity at single tertiary care center between 2011 and 2017. A total of 1107 scans were identified for these pregnancies and maternal and obstetrical data were reviewed. Women 18–40 years of age with low-risk pregnancies and established dating consistent with first trimester ultrasound scan were included. Exclusion criteria were any maternal, fetal or obstetrical conditions known to affect fetal growth. Results Estimated fetal weight among Somali pregnancies differed significantly at some time points from the NICHD four ethnic groups, but generally the EFW graph curves crossed over at most time points between the study groups. At week 18, EFW was significantly larger than all other four ethnic groups (all p<.001), it was also significantly larger from the Hispanic, Black, and Asian ethnic groups at some time points between 18 and 27 weeks gestation (p < .05). Additionally, EFW among Somali pregnancies was significantly smaller than the Black and Asian ethnicity at 32 and 35–36 weeks and smaller than the White ethnicity at 30 and 38–39 weeks (p < .05). Abdominal circumference (AC) for the Somali population was significantly smaller than the other ethnic groups, especially than the White ethnicity at various time points across 16–40 weeks (p < .05). Femur and humerus length were significantly longer when compared to all other ethnic groups at most time points from 16 to 40 weeks of gestation (p < .05). Biparietal diameter (BPD) was significantly smaller than all other ethnic groups specifically at time of fetal survey (18 weeks) and at time of fetal growth assessment (32 weeks) (p < .05). Conclusions Significant differences in fetal growth standards were found between the Somali ethnicity and other ethnic groups (White, Black, Asian, and Hispanic) at various time points from 16 to 40 weeks of gestation. Racial/ethnic-specific standards improve the precision for evaluating fetal growth and may decrease the proportion of fetuses of Somali ethnicity labeled as small-for-gestational age.

This study aimed to evaluate the performance of sonographic biometric and Doppler parameters assessed at a routine third trimester scan, in combination with maternal characteristics, in predicting small-for-gestational-age (SGA) neonates and adverse perinatal outcomes. This was a cohort study of low-risk singleton pregnancies undergoing routine ultrasound between 35+0 and 37+6 weeks. Demographic characteristics, estimated fetal weight (EFW) and abdominal circumference (AC) centiles, and Doppler indices, including the Pulsatility Index (PI) of the Umbilical Artery (UA), Middle Cerebral Artery (MCA), and Uterine Artery (UtA) were evaluated. The Cerebroplacental ratio (CPR) was calculated, all indices were converted into Multiples of the Median (MoM). Multivariable logistic regression analysis was performed. Receiver-operating curves (ROC) were created to determine factors predictive of an SGA neonate with birthweights <3rd, 5th, and 10th centile and composite adverse perinatal outcomes (CAPO), which was comprised of intrauterine death, neonatal death, and neonatal intensive care unit admission. A total of 14,161 pregnancies were included. EFW centile (adjusted odds ratio (aOR) 0.91 (95% CI, 0.9-0.92), p < 0.001) (aOR 0.9 (95% CI, 0.89-0.91), p < 0.001), UA PI (aOR 4.6 (95% CI, 2.2-9.6), p < 0.001) (aOR 2.5 (95% CI, 1.1-6.1), p < 0.04), MCA PI (aOR 0.37 (95% CI, 0.2-0.7), p = 0.002) (aOR 0.26 (95% CI, 0.12-0.59), p = 0.001), CPR (aOR 0.23 (95% CI, 0.13-0.42), p < 0.001) (aOR 0.25 (95% CI, 0.12-0.53), p < 0.001), and UtA PI (aOR 2.5 (95% CI, 1.68-3.83), p < 0.001) (aOR 2.2 (95% CI, 1.31-3.6), p = 0.003) were independent predictors of SGA <5th and SGA <3rd or SGA with CAPO, respectively. The combination of EFW, CPR, and UtA PI was associated with an Area under the curve (AUC) of 0.93 (95% CI 0.92-0.94), p < 0.001 for both outcomes. In an unselected population, the UA PI, MCA PI, CPR, and UtA PI are independent predictors of SGA and adverse perinatal outcomes. The combination of these parameters can reliably predict SGA and adverse perinatal outcomes with a high degree of accuracy.

Objectives: To compare two-dimensional (2D) and threedimensional (3D) ultrasound techniques, including volumetry of fetal thigh, for weight estimation of large fetuses, and to develop a new fetal weight (FW) estimation formula. Methods: In a prospective comparative study FW estimation was done on 176 pregnant women at ≥287 days of gestation ≤ 4 days before delivery. Fetal head (BPD or HC), abdomen (AD) and femur were measured with 2D ultrasound technique and the volume of fetal thigh (Tvol) was estimated with 3D technique. The 2D formula of Persson and Weldner (1) was compared with the 3D formula of Lee et al(2). A new formula was developed in a subgroup of 63 fetuses where volumetry of abdomen (Abdvol) was done and the formula (FW = 2088.4904 + 81.0519 × HC − 0.1214 × HC × HC − 69.0966 × AD + 0.4741 × AD × AD + 6.4044 × Tvol + 0.0534 × Abdvol) was tested on another 50 women. Results: Standard deviation (SD) of the mean percent error (MPE) was 6.3% for both the 2D and 3D formulas, and 5.6% for the new formula. Significantly more FW estimated by the 2D formula and the new formula than by the 3D formulas were within both ±5% and ±10% of the birth weight, 50 and 86% (Persson and Weldner), 52 and 86% (new formula), 41 and 73% (Lee), respectively. In the independent Test group the SD of MPE was similar for the 2D, 3D and new formulas, 7.02, 7.04 and 7.09%, respectively. Conclusion: FW of large fetuses was estimated using 2D ultrasound method with same accuracy as with 3D ultrasound. 3D ultrasound technique requires technically advanced and expensive equipment, special operator training and skills, and it is time consuming. At present, to abandon the 2D ultrasound method in favour of 3D ultrasound for FW estimation seems not reasonable.

Maternal urinary bisphenols and phthalates in relation to estimated fetal weight across mid to late pregnancy