OBJECTIVE: To elucidate the association between arterial and venous Doppler ultrasound parameters and the risk of secondary cesarean delivery for intrapartum fetal compromise (IFC) and neonatal acidosis in small-for-gestational-age (SGA) fetuses.
METHODS: This single-center, prospective, blinded, cohort study included singleton pregnancies with an estimated fetal weight (EFW) < 10th centile above 36 gestational weeks. Upon study inclusion, all women underwent Doppler ultrasound, including umbilical artery (UA) pulsatility index (PI), middle cerebral artery (MCA) PI, fetal aortic isthmus (AoI) PI, umbilical vein blood flow (UVBF), and modified myocardial performance index (mod-MPI). Primary outcome was defined as secondary cesarean section due to IFC.
RESULTS: In total, 87 SGA pregnancies were included, 16% of which required a cesarean section for IFC. Those fetuses revealed lower UVBF corrected for abdominal circumference (AC) (5.2 (4.5-6.3) vs 7.2 (5.5-8.3), p = 0.001). There was no difference when comparing AoI PI, UA PI, ACM PI, or mod-MPI. No association was found for neonatal acidosis. After multivariate logistic regression, UVBF/AC remained independently associated with cesarean section due to IFC (aOR 0.61 [0.37; 0.91], p = 0.03) and yielded an area under the curve (AUC) of 0.78 (95% CI, 0.67-0.89). A cut-off value set at the 50th centile of UVBF/AC reached a sensitivity of 86% and specificity of 58% for the occurrence of cesarean section due to IFC (OR 8.1; 95% CI, 1.7-37.8, p = 0.003).
CONCLUSIONS: Low levels of umbilical vein blood flow (UVBF/AC) were associated with an increased risk among SGA fetuses to be delivered by cesarean section for IFC.

BACKGROUND: To evaluate the maternal and fetal hemodynamic effects of treatment with a nitric oxide donor and oral fluid in pregnancies complicated by fetal growth restriction.
METHODS: 30 normotensive participants with early fetal growth restriction were enrolled. 15 participants were treated until delivery with transdermal glyceryl trinitrate and oral fluid intake (Treated group), and 15 comprised the untreated group. All women underwent non-invasive assessment of fetal and maternal hemodynamics and repeat evaluation 2 weeks later.
RESULTS: In the treated group, maternal hemodynamics improved significantly after two weeks of therapy compared to untreated participants. Fetal hemodynamics in the treated group showed an increase in umbilical vein diameter by 18.87 % (p < 0.01), in umbilical vein blood flow by 48.16 % (p < 0.01) and in umbilical vein blood flow corrected for estimated fetal weight by 30.03 % (p < 0.01). In the untreated group, the characteristics of the umbilical vein were unchanged compared to baseline. At the same time, the cerebro-placental ratio increased in the treated group, while it was reduced in the untreated group, compared to baseline values. The treated group showed a higher birthweight centile (p = 0.03) and a lower preeclampsia rate (p = 0.04) compared to the untreated group.
CONCLUSIONS: The combined therapeutic approach with nitric oxide donor and oral fluid intake in fetal growth restriction improves maternal hemodynamics, which becomes more hyperdynamic (volume-dominant). At the same time, in the fetal circuit, umbilical vein flow increased and fetal brain sparing improved. Although a modest sample size, there was less preeclampsia and a higher birthweight suggesting beneficial maternal and fetal characteristics of treatment.

OBJECTIVE: To investigate midbrain growth, including corpus callusum (CC) and cerebellar vermis (CV) and cortical development in late fetal growth restricted (FGR) subclassified according to the umbilical vein blood flow (UVBF) values.
METHODS: This was a prospective study on singleton fetuses late FGR with abnormal placental cerebral ratio (PCR). FGR fetuses were further subdivided into normal (≥fifth centile) and abnormal (RESULTS: The study cohort included 60 late FGR, 31 with normal UVBF/AC and 29 with abnormal UVBF/AC values. The latter group showed significant differences in CC (median (interquartile range (IQR) normal 0.96 (0.73-1.16) vs. abnormal UVBF/AC 0.60 (0.47-0.87); p<0.0001)), CV (normal 1.04 (0.75-1.26) vs. abnormal UVBF (AC 0.76 (0.62-1.18)); p=0.0319), SF (normal 0.83 (0.74-0.93) vs. abnormal UVBF/AC 0.56 (0.46-0.68); p<0.0001), POF (normal 0.80 (0.71-0.90) vs. abnormal UVBF/AC l 0.49 (0.39-0.90); p≤0.0072) and CF (normal 0.83 (0.56-1.01) vs. abnormal UVBF/AC 0.72 (0.53-0.80); p<0.029).
CONCLUSIONS: Late onset FGR fetuses with of reduced umbilical vein flow showed shorter CC and CV length and a delayed cortical development when compared to those with normal umbilical vein hemodynamics. These findings support the existence of a link between abnormal brain development and changes in umbilical vein circulation.

Twin-twin transfusion syndrome (TTTS) is characterized by unequal hemodynamics between the twins. We aimed to assess preoperatively the difference in umbilical vein flow (UVF) between the recipient and donor monochorionic diamniotic twins and evaluate the change in UVF following laser surgery in both twins.
This was a retrospective cohort study of differences in UVF that occurred following laser surgical treatment of TTTS. Sonographic assessment of the umbilical vein before and 24 h after fetoscopic laser surgery for TTTS was performed. Umbilical vein diameter and time-averaged maximum velocity were measured, and UVF per kg (UVF/kg) was converted into a Z-score by a calculator created using gestational age as an independent variable. Z-score values were converted into centiles, which were evaluated statistically. Median differences in UVF/kg centile values were adjusted for TTTS stage and presence of arterioarterial anastomoses.
The study population consisted of 363 TTTS patients. The adjusted preoperative median difference in UVF/kg centile between the recipient vs donor twin was 17.9% (-17.1% to 57.6%), P < 0.0001. The adjusted median difference in UVF/kg centile between the postoperative vs preoperative period among recipients was 2.2% (-10.8% to 13.8%), P < 0.0001, while the adjusted median difference among donors was 27.3% (8.2%-34.6%), P < 0.0001.
The preoperative difference in UVF between the recipient and donor twins confirms the pathophysiology of TTTS. Postoperatively, the substantial increase in UVF of the donor twin and the relatively small increase in UVF of the recipient twin confirm that ablation of the vascular communications resulted in rapid improvement in perfusion of the donor twin. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

The functional maternal-fetal hemodynamic unit includes fetal umbilical vein flow and maternal peripheral vascular resistance.
This study investigated the relationships between maternal and fetal hemodynamics in a population with suspected fetal growth restriction.
This was a prospective study of normotensive pregnancies referred to our outpatient clinic for a suspected fetal growth restriction. Maternal hemodynamics measurement was performed, using a noninvasive device (USCOM-1A) and a fetal ultrasound evaluation to assess fetal biometry and velocimetry Doppler parameters. Comparisons among groups were performed with 1-way analysis of variance with Student-Newman-Keuls correction for multiple comparisons and with Kruskal-Wallis test where appropriate. The Spearman rank coefficient was used to assess the correlation between maternal and fetal hemodynamics. Pregnancies were observed until delivery.
A total of 182 normotensive pregnancies were included. After the evaluation, 54 fetuses were classified as growth restricted, 42 as small for gestational age, and 86 as adequate for gestational age. The fetus with fetal growth restriction had significantly lower umbilical vein diameter (P<.0001), umbilical vein velocity (P=.02), umbilical vein flow (P<.0001), and umbilical vein flow corrected for fetal weight (P<.01) than adequate-for-gestational-age and small-for-gestational-age fetuses. The maternal hemodynamic profile in fetal growth restriction was characterized by elevated systemic vascular resistance and reduced cardiac output. The umbilical vein diameter was positively correlated to maternal cardiac output (rs=0.261), whereas there was a negative correlation between maternal systemic vascular resistance (rs=-0.338) and maternal potential energy-to-kinetic energy ratio (rs=-0267). The fetal umbilical vein time averaged max velocity was positively correlated to maternal cardiac output (rs=0.189) and maternal inotropy index (rs=0.162), whereas there was a negative correlation with maternal systemic vascular resistance (rs=-0.264) and maternal potential energy-to-kinetic energy ratio (rs=-0.171). The fetal umbilical vein flow and the flow corrected for estimated fetal weight were positively correlated with maternal cardiac output (rs=0.339 and rs=0.297) and maternal inotropy index (rs=0.217 and r=0.336), whereas there was a negative correlation between maternal systemic vascular resistance (rs=-0.461 and rs=-0.409) and maternal potential energy-to-kinetic energy ratio (rs=-0.336 and rs=-0.408).
Maternal and fetal hemodynamic parameters were different in the 3 groups of fetuses: fetal growth restriction, small for gestational age, and adequate for gestational age. Maternal hemodynamic parameters were closely and continuously correlated with fetal hemodynamic features. In particular, a maternal hemodynamic profile with high systemic vascular resistance, low cardiac output, reduced inotropism, and hypodynamic circulation was correlated with a reduced umbilical vein flow and increased umbilical artery pulsatility index. The mother, placenta, and fetus should be considered as a single cardiac-fetal-placental unit. The correlations of systemic vascular resistance, cardiac output, and inotropy index with umbilical artery impedance indicate the key role of these 3 parameters in placental vascular tree development. The umbilical vein flow rate and, therefore, the placental perfusion seems to be influenced not only by these three parameters but also by the maternal cardiovascular kinetic energy.

OBJECTIVE: To explore whether severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can affect umbilical vein blood flow (UVBF) and fetal cardiac function.
METHODS: Prospective case-control study of consecutive pregnancies complicated by SARS-CoV-2 infection during the second half of pregnancy matched with unaffected women. Measurements of UVBF normalized for fetal abdominal circumference (UVBF/AC), atrial area (AA) and ventricular sphericity indices (SI) were compared between the two study groups. Chi-square and Mann-Whitney U tests were sued to analyze the data.
RESULTS: Fifty-four consecutive pregnancies complicated and 108 not complicated by SARS-CoV-2 infection were included. The median gestational age at infection was 30.2 (interquartile range [IQR] 26.2 34.1). General baseline and pregnancy characteristics were similar between pregnant women with compared to those without SARS-CoV-2 infection. There was no difference in UVBF/AC (study groups z value -0.11 vs. 0.14 control p 0.751) values between pregnancies complicated compared to those not complicated by SARS-CoV-2 infection. Likewise, there was no difference in the left and right AA (left 1.30 vs. 1.28 p=0.221 and right 1.33 vs. 1.31 p=0.324) and SI (left 1.75 vs. 1.77 p=0.208 and right 1.51 vs. 1.54 p=0.121) between the two groups.
CONCLUSIONS: SARS-CoV-2 infection does not affect UVBF and fetal cardiac function in uncomplicated pregnancies.

BACKGROUND: Measurements of the umbilical vein diameter (UVD) and blood flow (mL/min) (UVF) have been demonstrated to be decreased in fetuses with growth restriction (FGR) using gestational age (GA) as the independent variable. However, no previous studies have used the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC), femur length (FL), and the estimated fetal weight (EFW) to create equations to be used for z-score computations when evaluating fetuses at risk foran abnormal UVD and UVF.
METHODS: Two hundred and forty normal fetuses between 20 and 40 weeks of gestation were examined in which the UVD and time averaged maximal velocity (TAMX) were measured from which the UVF, UVF/HC, UVF/AC, and UVF/kg were computed. Fractional polynomial regression analysis was used to compute z-score equations using the above independent variables. Thirty-six fetuses with abnormal growth of the AC were examined to test the validity of the equations.
RESULTS: The UVD, TAMX, UVF, UVF/HC, and UVF/AC all increased with gestatonal age and fetal growth except for the UVF/kg, which decreased with age and growth. From the regression equations, two z-score calculators were created using an Excel spreadsheet that can be used in clinical practice. Abnormal measurements of the UVD, UVF, UVF/HC, UVF/AC, and UVF/kg were observed in the 36 study fetuses, 21 with an AC < 10th centile and 15 with an AC > 90th centile.
CONCLUSIONS: Using the equations generated from this study and the z-score calculators provides a clinical tool to measure the size and flow of the umbilical vein that may have clinical implications.

Background Altered cardiac geometry affects a proportion of fetuses with growth restriction (FGR). The aim of this study was to explore the hemodynamic factors associated with cardiac remodeling in late FGR. Methods This was a prospective study of singleton pregnancies complicated by late-onset FGR undergoing assessment of left (LV) and right (RV) ventricular sphericity-index (SI). The study population was divided in two groups according to the presence of cardiac remodelling, defined as LVSI <5th centile. The following outcomes were explored: gestational age at birth, birthweight, caesarean section (CS) for fetal distress, umbilical artery (UA) pH and neonatal admission to special care unit. The differences between the 2 groups in UA pulsatility index (PI), middle cerebral artery (MCA) PI, uterine artery PI, cerebroplacental ratio (CPR) and umbilical vein (UV) flow corrected for fetal abdominal circumference (UVBF/AC) were tested. Results In total, 212 pregnancies with late FGR were enrolled in the study. An abnormal LV SI was detected in 119 fetuses (56.1%). Late FGR fetuses with cardiac remodeling had a lower birthweight (2390 g vs. 2490; P = 0.04) and umbilical artery pH (7.21 vs. 7.24; P = 0.04) and were more likely to have emergency CS (42.8% vs. 26.9%; P = 0.023) and admission to special care unit (13.4% vs. 4.3%; P = 0.03) compared to those with normal LVSI. No difference in either UA PI (p = 0.904), MCA PI (P = 0.575), CPR (P = 0.607) and mean uterine artery PI (P = 0.756) were present between fetuses with or without an abnormal LV SI. Conversely, UVBF/AC z-score was lower (-1.84 vs. -0.99; P ≤ 0.001) in fetuses with cardiac remodeling and correlated with LV (P ≤ 0.01) and RV SI (P ≤ 0.02). Conclusion Fetal cardiac remodelling occurs in a significant proportion of pregnancies complicated by late FGR and is affected by a high burden of short-term perinatal compromise. The occurrence of LV SI is independent from fetal arterial Dopplers while it is positively associated with umbilical vein blood flow.

Pregnancies complicated by late-onset fetal growth restriction (FGR) are at increased risk of short- and long-term morbidities. Despite this, identification of cases at higher risk of adverse perinatal outcome, at the time of FGR diagnosis, is challenging. The aims of this study were to elucidate the strength of association between fetoplacental Doppler indices at the time of diagnosis of late-onset FGR and adverse perinatal outcome, and to determine their predictive accuracy.
This was a prospective study of consecutive singleton pregnancies complicated by late-onset FGR. Late-onset FGR was defined as estimated fetal weight (EFW) or abdominal circumference (AC) < 3rd centile, or EFW or AC < 10th centile and umbilical artery (UA) pulsatility index (PI) > 95th centile or cerebroplacental ratio (CPR) < 5th centile, diagnosed after 32 weeks. EFW, uterine artery PI, UA-PI, fetal middle cerebral artery (MCA) PI, CPR and umbilical vein blood flow normalized for fetal abdominal circumference (UVBF/AC) were recorded at the time of the diagnosis of FGR. Doppler variables were expressed as Z-scores for gestational age. Composite adverse perinatal outcome was defined as the occurrence of at least one of emergency Cesarean section for fetal distress, 5-min Apgar score < 7, umbilical artery pH < 7.10 and neonatal admission to the special care unit. Logistic regression analysis was used to elucidate the strength of association between different ultrasound parameters and composite adverse perinatal outcome, and receiver-operating-characteristics (ROC)-curve analysis was used to determine their predictive accuracy.
In total, 243 consecutive singleton pregnancies complicated by late-onset FGR were included. Composite adverse perinatal outcome occurred in 32.5% (95% CI, 26.7-38.8%) of cases. In pregnancies with composite adverse perinatal outcome, compared with those without, mean uterine artery PI Z-score (2.23 ± 1.34 vs 1.88 ± 0.89, P = 0.02) was higher, while Z-scores of UVBF/AC (-1.93 ± 0.88 vs -0.89 ± 0.94, P ≤ 0.0001), MCA-PI (-1.56 ± 0.93 vs -1.22 ± 0.84, P = 0.004) and CPR (-1.89 ± 1.12 vs -1.44 ± 1.02, P = 0.002) were lower. On multivariable logistic regression analysis, Z-scores of mean uterine artery PI (P = 0.04), CPR (P = 0.002) and UVBF/AC (P = 0.001) were associated independently with composite adverse perinatal outcome. UVBF/AC Z-score had an area under the ROC curve (AUC) of 0.723 (95% CI, 0.64-0.80) for composite adverse perinatal outcome, demonstrating better accuracy than that of mean uterine artery PI Z-score (AUC, 0.593; 95% CI, 0.50-0.69) and CPR Z-score (AUC, 0.615; 95% CI, 0.52-0.71). A multiparametric prediction model including Z-scores of MCA-PI, uterine artery PI and UVBF/AC had an AUC of 0.745 (95% CI, 0.66-0.83) for the prediction of composite adverse perinatal outcome.
While CPR and uterine artery PI assessed at the time of diagnosis are associated independently with composite adverse perinatal outcome in pregnancies complicated by late-onset FGR, their diagnostic performance for composite adverse perinatal outcome is low. UVBF/AC showed better accuracy for prediction of composite adverse perinatal outcome, although its usefulness in clinical practice as a standalone predictor of adverse pregnancy outcome requires further research. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
Papel de la ecografía Doppler en el momento del diagnóstico de la restricción del crecimiento fetal de aparición tardía para la predicción de resultados perinatales adversos: estudio prospectivo de cohortes OBJETIVO: Los embarazos complicados por la restricción del crecimiento fetal (RCF) de aparición tardía tienen un mayor riesgo de morbilidad a corto y largo plazo. A pesar de ello, es difícil identificar los casos con mayor riesgo de resultados perinatales adversos en el momento del diagnóstico de RCF. Los objetivos de este estudio fueron dilucidar la fortaleza de la asociación entre los índices Doppler fetoplacentarios en el momento del diagnóstico de la RCF de aparición tardía y el resultado perinatal adverso, y determinar su precisión predictiva. MÉTODOS: Este fue un estudio prospectivo de embarazos consecutivos con feto único complicados por una RCF de aparición tardía. La aparición tardía de la RCF se definió como peso estimado del feto (PEF) o circunferencia abdominal (CA) <3er percentil, o PEF o CA <10o percentil junto con índice de pulsatilidad (IP) de la arteria umbilical (AU) >95o percentil, o una relación cerebroplacentaria (RCP) <5o percentil, diagnosticado después de las 32 semanas. El PEF, el IP de la arteria uterina (IP-AU), el IP de la arteria cerebral media fetal (ACM), la RCP y el flujo sanguíneo de la vena umbilical normalizado para la circunferencia abdominal fetal (UVBF/AC, por sus siglas en inglés) se registraron en el momento del diagnóstico de RCF. Las variables Doppler se expresaron como puntuaciones Z para la edad gestacional. El resultado perinatal adverso compuesto se definió como la ocurrencia de al menos una cesárea de emergencia por sufrimiento fetal, test de Apgar a los 5 minutos <7, pH de la arteria umbilical <7,10 y el ingreso a la unidad de cuidados especiales de recién nacidos. Se utilizó el análisis de regresión logística para dilucidar la fortaleza de la asociación entre los diferentes parámetros de la ecografía y el resultado perinatal adverso compuesto, y se empleó el análisis de la curva de características operativas del receptor (ROC, por sus siglas en inglés) para determinar su precisión predictiva. RESULTADOS: En total, se incluyeron 243 embarazos con feto único consecutivos complicados por RCF de aparición tardía. El resultado perinatal adverso compuesto se produjo en el 32,5% (IC 95%, 26,7-38,8%) de los casos. En los embarazos con resultados perinatales adversos compuestos, en comparación con los que no los tuvieron, la puntuación Z del IP de la arteria uterina media (2,23±1,34 vs 1,88±0,89, P=0,02) fue mayor, mientras que las puntuaciones Z de UVBF/AC (-1,93±0,88 vs -0,89±0,94, P≤0,0001), IP-ACM (-1,56±0,93 vs -1,22±0,84, P=0,004) y RCP (-1,89±1,12 vs -1,44±1,02, P=0,002) fueron más bajas. En el análisis de regresión logística multivariable, las puntuaciones Z del IP de la arteria uterina media (P=0,04), RCP (P=0,002) y UVBF/AC (P=0,001) estuvieron asociadas de forma independiente con el resultado perinatal adverso compuesto. La puntuación Z del UVBF/AC tuvo un área bajo la curva (ABC) ROC de 0,723 (IC 95%, 0,64-0,80) para el resultado perinatal adverso compuesto, demostrando una mejor precisión que la de la puntuación Z del IP de la arteria uterina media (ABC, 0,593; IC 95%, 0,50-0,69) y la de la puntuación Z de la RCP (ABC, 0,615; IC 95%, 0,52-0,71). Un modelo de predicción multiparamétrico que incluía las puntuaciones Z del IP-ACM, el IP de la arteria uterina y el UVBF/AC resultó en un ABC de 0,745 (IC 95%, 0,66-0,83) para la predicción de un resultado perinatal adverso compuesto. CONCLUSIÓN: Aunque la RCP y el IP de la arteria uterina evaluados en el momento del diagnóstico están asociados de forma independiente con un resultado perinatal adverso compuesto en embarazos complicados por una RCF de aparición tardía, la eficacia del diagnóstico para el resultado perinatal adverso compuesto es baja. El UVBF/AC mostró una mayor precisión para la predicción de un resultado perinatal adverso compuesto, aunque su utilidad en la práctica clínica como parámetro indicativo independiente del resultado adverso del embarazo requiere más investigación. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.
多普勒超声在诊断迟发性胎儿生长受限时预测不良围产儿结局中的作用:前瞻性队列研究 目标: 妊娠合并迟发性胎儿生长受限(FGR)孕妇的短期长期发病风险增加。即便如此，在FGR诊断中确定高风险围产儿不良结局病例依然很困难。本研究旨在阐明迟发性胎儿生长受限诊断时胎儿胎盘多普勒指数与不良围产儿结局之间的关联强度，并确定其预测准确性。 方法: 这是一项针对连续单胎妊娠合并迟发性胎儿生长受限的前瞻性研究。迟发性FGR定义为32周诊断发现估算胎儿体重(EFW)或腹围(AC)<第3百分位数，或EFW或AC<第10百分位数且脐动脉(UA)搏动指数(PI)>第95百分位数，或脑胎盘比率(CPR)<第5百分位数。FGR诊断过程中记录了EFW、子宫动脉PI、UA-PI、胎儿大脑中动脉(MCA)PI、CPR，以及胎儿腹围脐静脉血流正常化(UVBF/AC)。以胎龄的Z评分表示多普勒变量。围产期综合不良结局定义为 发生至少1例胎儿窘迫急诊剖宫产、5分钟Apgar评分<7、脐动脉pH<7.10、新生儿入院接受特殊护理。通过逻辑回归分析探讨不同超声参数与围产期综合不良结局之间的关联强度，通过受体操作特征(ROC)曲线分析 确定其预测准确性。 结果: 总共包括243例连续单胎妊娠并发迟发性FGR。32.5%(95%CI，26.7-38.8%)的病例出现复合不良围产期结局。相比那些并无复合不良围产期结局的孕妇，复合不良围产期结局孕妇的平均子宫动脉PI Z评分(2.23±1.34对1.88±0.89，P=0.02)较高，而UVBF/AC的Z评分(-1.93±0.88对-0.89±0.94，P≤0.0001)、MCA-PI(-1.56±0.93 对-1.22±0.84，P=0.004)和CPR(-1.89±1.12对-1.44±1.02，P=0.002)较低。在多变量逻辑回归分析中，子宫动脉平均PI(P=0.04)、CPR(P=0.002)和UVBF/AC(P=0.001)的Z评分与复合不良围产期结局独立相关。UVBF/AC Z评分复合不良围产期结局ROC曲线下面积(AUC)为0.723(95%CI，0.64-0.80)，表明其准确性优于平均子宫动脉PI Z评分(AUC，0.593；95%CI，0.50-0.69)和CPR Z评分(AUC，0.615； 95%CI，0.52-0.71)。一个用于预测复合不良围产期结局且包括MCA-PI、子宫动脉PI和UVBF/AC的Z评分在内的多参数预测模型，其AUC为0.745(95%CI，0.66-0.83)。 结论: 虽然在诊断时接受评估的CPR和子宫动脉PI与妊娠并发迟发性FGR复合不良围产期结局独立相关，但它们的复合不良围产期结局诊出性较低。UVBF/AC在复合不良围产期结局的预测上更加准确，虽然它作为不良妊娠结局的独立预测指标在临床实践中的有用性有待进一步研究确定。版权 © 2019 ISUOG。由威利父子公司(John Wiley & Sons Ltd)出版。.