Estimated Fetal Weight Research Articles

Effect of Maternal Body Mass Index on The Accuracy of Sonographic Estimation of Foetal Weight in Late Gestation

Effect of Maternal Body Mass Index on The Accuracy of Sonographic Estimation of Foetal Weight in Late Gestation

OP06.04: Comprehensive audit of estimation of fetal weight in preterm and term population in a tertiary centre

OP06.04: Comprehensive audit of estimation of fetal weight in preterm and term population in a tertiary centre

Information sharing and communication in management of large for gestational age babies in non‐diabetic mothers

Key content There is no specific UK guideline on how to identify or manage large for gestational age (LGA) fetuses in non‐diabetic mothers. There is conflicting evidence with regard to the optimal mode and timing of delivery in such women and babies in order to minimise the possible risks. Pre‐delivery patient–clinician discussion on management and mode of delivery in LGA babies can be challenging due to the lack of conclusive evidence and guidance for both screening and interventions, but it is crucial in order to facilitate information sharing, counselling and collaborative decision making. Decision‐making tools could help to facilitate these discussions and ensure ‘material risks’ are discussed. Learning objectives To be aware of the limitations of available methods for screening for LGA fetuses, specifically symphyseal fundal height and ultrasound estimation of fetal weight. To understand the lack of robust evidence for obstetric interventions, which makes it difficult to convey clear information in a practical and useful way. To consider the use of decision‐making tools (such as BRAIN and iDECIDE), which can provide a framework for shared decision making, particularly when the evidence is limited or conflicting. These tools offer a structure which empowers patients to weigh up information as well as assist clinicians in determining what is considered ‘material risk’ when counselling in line with the Montgomery ruling. Ethical issues The Montgomery ruling advises that doctors must discuss any ‘material risks’ involved in a proposed treatment and offer other reasonable alternatives. Clinicians, therefore, have a duty to be transparent about the lack of strong evidence to recommend one mode of birth over another but at the same time acknowledge that individual preference and perceptions need to be explored to enable personalised decision making.

EP14.18: Accuracy of sonographic fetal weight estimation and birthweight discordance in twin pregnancies

EP14.18: Accuracy of sonographic fetal weight estimation and birthweight discordance in twin pregnancies

EP25.13: Comparison of three methods of fetal weight estimation in patients with severe and morbid obesity: a prospective study

EP25.13: Comparison of three methods of fetal weight estimation in patients with severe and morbid obesity: a prospective study

EP25.26: Sonographic fetal weight estimations by residents

EP25.26: Sonographic fetal weight estimations by residents

Predicting Big Babies: Using Amniotic Fluid and Baby Weight Estimates

Background: Macrosomia or big baby is defined as a newborn with a birth weight of more than 4kg. Amniotic fluid index (AFI) which is estimated by adding length of deepest vertical pool in four corners of liquor in uterus is an indicator of fetal well-being. This parameter when combined with ultrasonographic estimated fetal weight can predict macrosomia accurately. Objective: To evaluate diagnostic accuracy of integrated examination with amniotic fluid index (AFI) and estimated fetal weight (EFW) for prediction of macrosomia. Study Design: Cross sectional study. Settings: Department of Obstetrics and Gynecology, Combined Military Hospital (CMH), Rawalpindi Pakistan. Duration: 6 months from 29th October 2019 to 28th April 2020. Methods: After meeting the inclusion criteria 250 females were enrolled. All patients underwent sonographic evaluation for AFI and EFW estimation. Patients were categorized as positive or negative for macrosomia. Then all females were followed-up in OPD till delivery. If birth weight was ≥4000 grams, then macrosomia was confirmed. Results: The average age of the females was 27.21 ± 4.59 years, there were 55(22%) females as nulliparous. The sensitivity, specificity, and diagnostic accuracy of integrated examination of AFI & EFW were 50%, 98.78%, & 98% for definition of macrosomia as base line. Conclusion: This study showed good diagnostic accuracy of integrated amniotic fluid index and ultrasound baby weight estimates as predictor of macrosomia having low sensitivity.

The effects of gestational diabetes mellitus on fetal growth: is it different for low-risk and medium-high-risk pregnant women?

It has been suggested that gestational diabetes mellitus (GDM) alters the growth trajectory of a fetus and increases the risk of abnormal birth weight. In spite of this, there is still a significant debate regarding the mode and optimal timing of diagnosing this condition. Our aim was to determine fetal growth velocity and birth biometry in pregnant women with GDM at varying risk levels. We conducted a cohort study involving 1023 pregnant women at a maternity hospital in Ma'anshan, China. All women completed an oral glucose tolerance test at 24-28 weeks' gestation. We measured fetal head circumference (HC), femoral length (FL), abdominal circumference (AC), biparietal diameter (BPD), and estimate fetal weight (EFW) by ultrasound at 17, 24, 31, and 35 weeks' gestation, respectively. Overall, 5115 ultrasound scans were performed. Among both low-risk and medium-high-risk pregnant women at 17-24 weeks' gestation, GDM exposure was associated with an increase in fetal growth velocity. Neonates born to women with GDM at medium-high risk had significantly larger birth weights than those born to women without GDM, while this was not observed in women at low risk. In medium-high-risk pregnant women, exposure to GDM has a greater effect on the fetus, leading to abnormal fetal growth velocity that lasts beyond week 24. It is evident from our results that the effects of GDM on fetal growth differ between medium-high-risk pregnant women and low-risk pregnant women, and therefore a different screening program based on the risk factor for GDM is warranted.

The adverse impact of maternal ozone exposure on fetal growth in utero and the interaction with residential greenness

This study aimed to investigate the effect of maternal ozone exposure on fetal growth during pregnancy, as well as the combined effect and interaction of ozone and residential greenness. We included a total of 14990 singleton pregnancies from the Fujian Birth Cohort Study. During pregnancy, fetal growth parameters including estimated fetal weight (EFW), femur length (FL), head circumference (HC), and abdominal circumference (AC). To investigate the associations between ozone exposure and the above-mentioned outcomes, generalized estimating equation approach and generalized linear regression were used, as appropriate. In the adjusted models, we observed that the Z scores of EFW (−0.031 (−0.048, −0.014)), FL (−0.021 (−0.038, −0.004)), and AC (−0.025 (−0.042, −0.007)) decreased with per interquartile range (IQR) increase of ozone concentration. Compared to participants with low ozone exposure and high NDVI, those with high ozone exposure and low NDVI experienced the largest decrease in Z scores for EFW (−0.049 (−0.079, −0.02)), FL (−0.034 (−0.063, −0.004)), HC (−0.034 (−0.065, −0.004)), and AC (−0.041 (−0.072, −0.01)), respectively. Interestingly, we discovered the effect modification of NDVI on the relationship between ozone exposure and fetal growth restriction (P for interaction < 0.05). This study established a negative relationship of maternal ozone exposure and fetal growth. Of importance, this study discovered the joint effect and interaction between ozone and residential greenness exposure.

Deep learning-based segmentation of whole-body fetal MRI and fetal weight estimation: assessing performance, repeatability, and reproducibility.

To develop a deep-learning method for whole-body fetal segmentation based on MRI; to assess the method's repeatability, reproducibility, and accuracy; to create an MRI-based normal fetal weight growth chart; and to assess the sensitivity to detect fetuses with growth restriction (FGR). Retrospective data of 348 fetuses with gestational age (GA) of 19-39weeks were included: 249 normal appropriate for GA (AGA), 19 FGR, and 80 Other (having various imaging abnormalities). A fetal whole-body segmentation model with a quality estimation module was developed and evaluated in 169 cases. The method was evaluated for its repeatability (repeated scans within the same scanner, n = 22), reproducibility (different scanners, n = 6), and accuracy (compared with birth weight, n = 7). A normal MRI-based growth chart was derived. The method achieved a Dice = 0.973, absolute volume difference ratio (VDR) = 1.8% and VDR mean difference = 0.75% ([Formula: see text]: - 3.95%, 5.46), and high agreement with the gold standard. The method achieved a repeatability coefficient = 4.01%, ICC = 0.99, high reproducibility with a mean difference = 2.21% ([Formula: see text]: - 1.92%, 6.35%), and high accuracy with a mean difference between estimated fetal weight (EFW) and birth weight of - 0.39% ([Formula: see text]: - 8.23%, 7.45%). A normal growth chart (n = 246) was consistent with four ultrasound charts. EFW based on MRI correctly predicted birth-weight percentiles for all 18 fetuses ≤ 10thpercentile and for 14 out of 17 FGR fetuses below the 3rd percentile. Six fetuses referred to MRI as AGA were found to be < 3rd percentile. The proposed method for automatic MRI-based EFW demonstrated high performance and sensitivity to identify FGR fetuses. Results from this study support the use of the automatic fetal weight estimation method based on MRI for the assessment of fetal development and to detect fetuses at risk for growth restriction. • An AI-based segmentation method with a quality assessment module for fetal weight estimation based on MRI was developed, achieving high repeatability, reproducibility, and accuracy. • An MRI-based fetal weight growth chart constructed from a large cohort of normal and appropriate gestational-age fetuses is proposed. • The method showed a high sensitivity for the diagnosis of small fetuses suspected of growth restriction.

An analytical cross-sectional study: determining gestational age using fetal clavicle length during the second trimester.

To investigate the correlation between fetal clavicle length and gestational age in pregnant patients from 14 and 27weeks of gestation. This was a retrospective cross-sectional study of patients from 14 and 27weeks of gestation. Ultrasonographic measurements such as abdominal circumference (AC), femur length (FL), humerus length (HL), clavicle length (CL), head circumference (HC), biparietal diameter (BPD), estimated fetal weight (EFW), and transverse cerebellum diameter (TCD) were made and compared. A total of 552 patients were evaluated in our clinic and CL was measured properly and successfully in all fetuses. Fetal AC, FL, HL, CL, BPD, HC, EFW and TCD measurements were significantly and strongly correlated with gestational week, and Pearson's correlation values were 0.964, 0.965, 0.959, 0.965, 0.951, 0.917, 0.925, and 0.954, respectively (p < 0.001). In the regression analysis equation, gestational week = 0.894 + CL × 0.961. There was a significant positive correlation between fetal CL (mm) and gestational week. We suggest that the 1mm = 1week rule can be used for patients with anomalies of the cerebellum and vermis, as well as for patients with unknown last menstrual period.

The impact of different growth charts on birthweight prediction: obstetrical ultrasound vs magnetic resonance imaging

The estimation of fetal weight (EFW) by fetal magnetic resonance imaging (MRI) is a simple and rapid method, with a high sensitivity to predict birthweight (BW) in comparison to ultrasound (US). Several national and international growth charts are currently in use but there is substantial heterogeneity among these charts due to: variations in the selected populations from which they were derived, different methodologies and statistical analysis of data. The purpose of this study was to compare the performance of MRI and US for the prediction of BW using three commonly used fetal growth charts: INTERGROWTH-21st (IG-21) project, World Health Organization (WHO), and Fetal Medicine Foundation (FMF). Data derived from a prospective, single center, blinded cohort study that compared the performance of MRI and US between 36+0/7 to 36+6/7 weeks of gestation (WG) for the prediction of BW ≥ 95th percentile was reanalyzed. EFW were categorized as > or < 5th, > or < 10th, > or < 90th, and > or < 95th percentile according to the three growth charts. BW was similarly categorized according to the BW standards of each chart. The performances of US and MRI for the prediction of BW < 5th, < 10th, > 90th, and > 95th percentile using the different growth charts were compared. Data were analysed with R software version 4.1.2. The comparison of sensitivity and specificity was done by McNemar and exact binomial tests. A p-value < 0.05 was considered as statistically significant. 2378 women were eligible for final analysis. US and MRI were performed at a median gestational age of 36+3/7 WG, delivery occurred at a median gestational age of 39+3/7 WG, and median BW was 3380 grams. The incidences of BW < 5th and < 10th percentiles were highest with the FMF chart and lowest with the IG-21 chart, whereas the incidences of BW > 90th and > 95th percentiles were lowest with the FMF chart and highest with the IG-21 chart. The sensitivity of MRI with an EFW > 95th percentile in the prediction of BW > 95th percentile was significantly higher than that of US across the three growth charts, however, its specificity was slightly lower than that of US. In contrast, the sensitivity of MRI with an EFW <10th percentile for predicting BW <10th percentile was significantly lower than US in the IG-21 and FMF charts, whereas the specificity and positive predictive value (PPV) of MRI were significantly higher than US for the three charts. Findings for the prediction of BW > 90th percentile were close to those of BW > 95th percentile, and findings for the prediction of BW < 5th percentile were close to those of BW < 10th percentile. The sensitivity of MRI is superior to US for the prediction of large for gestational age (LGA) fetuses and inferior to US for the prediction of small for gestational age (SGA) fetuses across the three different growth charts. The reverse is true for the specificity of MRI in comparison to the specificity of US.

Do differences in diagnostic criteria for late fetal growth restriction matter?

Criteria for diagnosis of fetal growth restriction differ widely according to national and international guidelines, and further heterogeneity arises from the use of different biometric and Doppler reference charts, making the diagnosis of fetal growth restriction highly variable. This study aimed to compare fetal growth restriction definitions between Delphi consensus and Society for Maternal-Fetal Medicine definitions, using different standards/charts for fetal biometry and different reference ranges for Doppler velocimetry parameters. From the TRUFFLE 2 feasibility study (856 women with singleton pregnancy at 32+0 to 36+6 weeks of gestation and at risk of fetal growth restriction), we selected 564 women with available mid-pregnancy biometry. For the comparison, we used standards/charts for estimated fetal weight and abdominal circumference from Hadlock, INTERGROWTH-21st, and GROW and Chitty. Percentiles for umbilical artery pulsatility index and its ratios with middle cerebral artery pulsatility index were calculated using Arduini and Ebbing reference charts. Sensitivity and specificity for low birthweight and adverse perinatal outcome were evaluated. Different combinations of definitions and reference charts identified substantially different proportions of fetuses within our population as having fetal growth restriction, varying from 38% (with Delphi consensus definition, INTERGROWTH-21st biometric standards, and Arduini Doppler reference ranges) to 93% (with Society for Maternal-Fetal Medicine definition and Hadlock biometric standards). None of the different combinations tested appeared effective, with relative risk for birthweight <10th percentile between 1.4 and 2.1. Birthweight <10th percentile was observed most frequently when selection was made with the GROW/Chitty charts, slightly less with the Hadlock standard, and least frequently with the INTERGROWTH-21st standard. Using the Ebbing Doppler reference ranges resulted in a far higher proportion identified as having fetal growth restriction compared with the Arduini Doppler reference ranges, whereas Delphi consensus definition with Ebbing Doppler reference ranges produced similar results to those of the Society for Maternal-Fetal Medicine definition. Application of Delphi consensus definition with Arduini Doppler reference ranges was significantly associated with adverse perinatal outcome, with any biometric standards/charts. The Society for Maternal-Fetal Medicine definition could not accurately detect adverse perinatal outcome irrespective of estimated fetal weight standard/chart used. Different combinations of fetal growth restriction definitions, biometry standards/charts, and Doppler reference ranges identify different proportions of fetuses with fetal growth restriction. The difference in adverse perinatal outcome may be modest, but can have a significant impact in terms of rate of intervention.

The Impact of the Active Stage of Labor on Estimate Fetal Weight: A Prospective Cohort Study

Objective: In the literature, there have been few data on ultrasound measurements during the active phase of labor. In this study, it was aimed to compare the accuracy of fetal weight estimation by ultrasound in terms of active phase of labor. Methods: This was a prospective cohort study at the obstetrics clinic of Esenler Gynecology and Children's Hospital in Istanbul. A total of 85 patients in active labor were included in the study. All pregnant women were evaluated for estimated fetal weight (EFW) by ultrasound evaluation, and cervical dilation and effacement measurements by pelvic examination, at most 24 hours before labor. Hadlock-4 formula was used for EFW. EFW and actual birth weight (ABW) and absolute errors of pregnant women in active labor were compared. Results: The mean EFW and ABW of the patients were 3161±482 and 3150±476 g, respectively. In terms of EFW and ABW, a finding in favor of the ultrasound was found. The error and error rates between EFW and ABW were found to be 234±191 g and 7.6±6.2, respectively. No significant difference was found in terms of these parameters (p&amp;gt;0.05). A significant and strong (0.80) correlation was found with estimated fetal weights and actual birth weights. Conclusion: Ultrasound can be used as a safe method to measure estimated fetal weight in the active phase of labor.

Fetal weight estimation based on deep neural network: a retrospective observational study

BackgroundImproving the accuracy of estimated fetal weight (EFW) calculation can contribute to decision-making for obstetricians and decrease perinatal complications. This study aimed to develop a deep neural network (DNN) model for EFW based on obstetric electronic health records.MethodsThis study retrospectively analyzed the electronic health records of pregnant women with live births delivery at the obstetrics department of International Peace Maternity & Child Health Hospital between January 2016 and December 2018. The DNN model was evaluated using Hadlock’s formula and multiple linear regression.ResultsA total of 34824 live births (23922 primiparas) from 49896 pregnant women were analyzed. The root-mean-square error of DNN model was 189.64 g (95% CI 187.95 g—191.16 g), and the mean absolute percentage error was 5.79% (95%CI: 5.70%—5.81%), significantly lower compared to Hadlock’s formula (240.36 g and 6.46%, respectively). By combining with previously unreported factors, such as birth weight of prior pregnancies, a concise and effective DNN model was built based on only 10 parameters. Accuracy rate of a new model increased from 76.08% to 83.87%, with root-mean-square error of only 243.80 g.ConclusionsProposed DNN model for EFW calculation is more accurate than previous approaches in this area and be adopted for better decision making related to fetal monitoring.

Corpus callosum-fastigium and tectal lengths in late-onset small fetuses.

To investigate measurements on neurosonography of midbrain morphology, including corpus callosum-fastigium length and tectal length, in late-onset small fetuses subclassified as small-for-gestational-age (SGA) or growth-restricted (FGR). This was a case-control study of consecutive singleton pregnancies delivered at term at a single center between January 2019 and July 2021, including those with late-onset smallness (estimated fetal weight (EFW) < 10th centile) and appropriate-for-gestational-age controls matched by age at neurosonography. Small fetuses were further subdivided into SGA (EFW between 3rd and 9th centile and normal fetoplacental Doppler) and FGR (EFW < 3rd centile or EFW < 10th centile with abnormal cerebroplacental ratio and/or uterine artery Doppler). Transvaginal neurosonography was performed at a mean ± SD gestational age of 33 ± 1 weeks in all fetuses to evaluate corpus callosum-fastigium length and tectal length in the midsagittal plane. Intra- and interobserver agreement was evaluated using the intraclass correlation coefficient and Bland-Altman plots. A total of 70 fetuses with late-onset smallness (29 with SGA and 41 with FGR) and 70 controls were included. Compared with controls, small fetuses showed significantly shorter corpus callosum-fastigium length (median (interquartile range), 44.7 (43.3-46.8) mm vs 43.7 (42.4-45.5) mm, P < 0.001) and tectal length (mean ± SD, 10.5 ± 0.9 vs 9.6 ± 1.0 mm, P < 0.001). These changes were more prominent in FGR fetuses, with a linear trend across groups according to severity of smallness. Corpus callosum-fastigium length and tectal length measurements showed excellent intra- and interobserver reliability. Small fetuses exhibited shorter corpus callosum-fastigium length and tectal length compared with controls, and these differences were more pronounced in fetuses with more severe smallness. These findings illustrate the potential value of midbrain measurements assessed on neurosonography as biomarkers for brain development in a high-risk population. However, further studies correlating these parameters with postnatal functional tests and follow-up are needed. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Fetal Growth Cut-Off Point To Predict Neonatal Outcome In Pregnancy With Normal And Deficient Vitamin D Levels: Intergrowth-21, World Health Organization Fetal Growth Curve, And Hadlock’s Estimated Fetal Weight

Purpose : Analyze the cut-off point of fetal growth based on the Intergrowth-21, World Health Organization (WHO), and Hadlock’s estimated fetal weight (EFW) in pregnant women with normal or deficient vitamin D levels to predict neonatal outcomes. Method: This cross sectional study to develop a diagnostic test, included 120 of pregnant women who completed follow up until children aged 2 years, divided into normal and deficient vitamin D group. Ultrasound and maternal vitamin D level examined during the second trimester of pregnancy. EFW was calculated using Hadlock’s formula and plotted on the Intergrowth-21 and WHO curves. The reference standards were the neonatal outcome, LBW, stunting, and neurocognitive impairment. Significant odds ratio (OR) value and area under the curve (AUC) of 0.6 are used to determine the cut-off point to be used. Result: Fetal growth curve was based on the WHO at the 5th percentile to predict LBW to have an AUC of 0.6 and OR of 6, 95% confidence interval (CI) of 1.36–26.45. The AUC for predicting LBW based on Intergrowth and Hadlock were 0.45 and OR not significant. As well as the AUC estimated stunting based on Hadlock, the Intergrowth-21 and the WHO fetal growth curves is &lt;0.6 with OR not statistically significant. The AUC predicted neurocognitive impairment based on WHO’s chart was 0.6 but OR not statistically significant. Conclusion: The WHO fetal growth curve can be used to predict LBW. The cut-off point of the fetal growth curve and which percentile is determined by the neonatal outcome.

Accuracy of Johnson's Formula for Estimating Fetal Weight Compared to Actual Birth Weight: A Study of 600 Cases in Rangpur Medical College

Introduction: The estimation of fetal weight during pregnancy has a significant impact on the survival of newborns and some immediate and late sequelae of the life of newborns. Estimation of fetal weight also plays a paramount role in determining time, mode, and place of delivery. There are many methods to estimate fetal weight like the palpation method, fundal height measurement, and radio frequency volume reduction. Johnson's method is one of the clinical methods that require no expense and is easier to estimate the precise birth weight and fetal weight. This study aimed to analyze the accuracy of the Johnsons formula for estimating fetal weight compared to actual birth weight. Methods: This cross-sectional prospective study took place in the Gynecology and Obstetrics Department of Rangpur Medical College Hospital, Rangpur, between May 2015 to October 2015, six (06) months after approval. The sample size was 600 as per inclusion criteria. Data were collected through face-to-face interviews with the women by using a pre- design questionnaire after proper counseling and informed written consent. The purposive sampling method was used in the study. Data processing was consisting of registration schedule, editing, computerization, preparation of dummy table, analyzing &amp; matching of data. Statistical analysis was carried out by using the Statistical Package for Social Sciences version 16.0 for Windows. The mean values were calculated for continuous variables. The quantitative observations were indicated by frequencies and percentages. Paired t-test was used for continuous variables. Pearson's correlation coefficients were used to test the relationship between the groups. P values &lt;0.05 was considered statistically significant. Result: The mean age was found 24.5±5.1 years with a range from 18 to 38 years. The mean symphysio fundal height was found 32.4±2.0 cm with a range from 28 to 36 cm. The mean estimated fetal weight was found 3205.2±287.9 grams with a range from 2635 to 3875 grams. The mean actual birth weight after delivery was found 3019.0±359.0 grams with a range from 2200 to 3800 grams. The difference was statistically significant (p&lt;0.05) between the two groups. A positive significant correlation (r=0.929; p=0.001) was found between actual birth weight and estimated fetal weight by Johnson's formula. A positive significant correlation (r=0.517; p=0.001) was found between actual birth weight and symphysio fundal height. A positive significant correlation (r=0.129; p=0.002) was also found between the actual birth weight neonate and the BMI of the mother. Conclusion: Antenatal and intranatal fetal weight can be estimated with reasonable accuracy, clinically using Johnson's formula. Ultrasound is not available in remote areas where Johnson's formula is easy and simple to calculate and can be included in the training program of medical and paramedical staff and birth attendants.

Subclassification of fetal growth restriction type IIa vs type IIb applied to twin-twin transfusion syndrome

Subclassification of monochorionic twins with selective fetal growth restriction (sFGR) type II into IIa vs. IIb has been proposed due to differing neonatal survival outcomes of the growth-restricted fetus after laser surgery based on preoperative Doppler findings in the middle cerebral artery (MCA) and ductus venosus (DV). There is substantial clinical overlap between sFGR and twin-twin transfusion syndrome (TTTS). To compare donor twin neonatal survival after laser surgery in cases of TTTS with concomitant donor FGR type IIa vs. IIb. This is a retrospective study of monochorionic multifetal gestations treated with laser for Stage III TTTS and concomitant donor twin FGR type II at a referral center from 2006-2021. Donor FGR type II was defined as having an estimated fetal weight (EFW) <10th percentile with persistent absent and/or reversed end diastolic velocity in the umbilical artery. Patients were then subclassified as type IIa (having normal MCA peak systolic velocities [psv] and DV Doppler waveforms) vs. type IIb (having MCA psv ≥1.5 multiples of the median and/or DV with persistent absent or reversed atrial systolic flow). We compared 30-day neonatal survival of the donor twin by FGR type IIa vs. IIb using logistic regression to adjust for relevant preoperative covariates (p<0.10 in bivariate analysis). Of 919 patients who underwent laser surgery for TTTS, 262 had Stage III donor or donor/recipient TTTS; of these, 189 (20.6%) had concomitant donor FGR type II. Twelve met exclusion criteria, yielding 177 patients (19.3%) who comprised the study cohort. Patients were subclassified as donor FGR type IIa (146 [82%]) vs. type IIb (31 [18%]). Donor neonatal survival for FGR type IIa vs. IIb was 71.2% vs. 41.9% (p=0.003). Recipient neonatal survival did not differ between the two types (p=1.000). Patients classified with TTTS and concomitant donor FGR type IIb were 66% less likely to have neonatal survival of the donor after laser surgery (adjusted OR=0.34, 95% CI 0.15-0.80; p=0.0127). The logistic regression model was adjusted for gestational age at the procedure, EFW percent discordance, and nulliparity. The c-statistic was 0.702. For patients with Stage III TTTS and concurrent donor FGR with persistent absent or reversed end diastolic velocity in the umbilical artery (i.e., FGR type II), subclassification into FGR type IIb based on elevated MCA psv and/or abnormal DV flow in the donor conveyed poorer prognosis. Although donor neonatal survival after laser surgery was lower for Stage III TTTS patients with donor FGR type IIb compared with type IIa, laser surgery for FGR type IIb in the setting of TTTS (as opposed to pure sFGR type IIb) still allows for the possibility of dual survivorship and should be offered with shared decision-making when counseling patients on management options.

The effects of prenatal PM2.5 oxidative potential exposure on feto-placental vascular resistance and fetal weight: A repeated-measures study

BackgroundFeto-placental hemodynamic deterioration is a critical contributing factor to fetal growth restriction. Whether PM2.5 oxidative potential (OP) affects feto-placental hemodynamics and what impact is on estimated fetal weight (EFW) have not been fully elucidated. We sought to evaluate the association of PM2.5 OP with EFW and to explore whether feto-placental vascular impedance hemodynamic change is a possible mediator in this association. MethodsA repeated-measures study was conducted involving sixty pregnant women with at least 26 weeks of follow-up during pregnancy in Guangzhou, China, from September 2017 to October 2018. Daily filter-based PM2.5 samples were prospectively collected from ground monitors, and estimates of OP for PM2.5 and its metallic (OPv-metal) and non-metallic constituents (OPv-nonmental) were determined by dithiothreitol assay. Ultrasound data of fetal growth and umbilical arterial resistance, including estimated fetal weight (EFW), pulsatility index, resistance index, and systolic-to-diastolic ratio, were also obtained during gestation. Generalized estimating equations and polynomial distribution lag models were applied to analyze the associations of maternal exposure to PM2.5 OP with EFW and umbilical artery indices. Causal mediation analysis was used to evaluate the mediating role of umbilical arterial resistance. ResultsPrenatal exposure to ambient PM2.5 OP was significantly inversely associated with EFW. The magnitudes of effects of OPv-nonmetal on EFW were larger than those of OPv-metal. Significant mediation for the relationship between PM2.5-related OP and EFW by increased impedance in the umbilical artery was observed, with the estimated percent mediated ranging from 31% to 61%. The estimated percent mediated for OPv-nonmetal was higher than those for OPv-metal. ConclusionsFindings suggest that increased impedance in the umbilical artery may be one of the potential mediators of the relationship between PM2.5 oxidative potential exposure and low fetal weight.