Outcome in early-onset fetal growth restriction is best combining computerized fetal heart rate analysis with ductus venosus Doppler: insights from the Trial of Umbilical and Fetal Flow in Europe

Late-onset fetal growth restriction management: a national survey

BACKGROUND

Fetal growth restriction (FGR) is an obstetric condition that increases the risk of adverse neonatal outcomes. FGR antenatal care aims to decrease fetal morbidity and mortality through optimal fetal monitoring. However, no univocal strategies for late-onset FGR outpatient management are available, and this survey investigated gynaecologists' attitudes concerning outpatient frequency tests.

METHODS

We mailed a survey to 429 Italian gynaecologists. The primary purpose was the ambulatory care of late-onset FGR without doppler alterations evaluation. The queries estimated the self-reported medical practice regarding cardiotocography (CTG) and obstetric ultrasound exams before hospitalization. Statistical analysis was performed with Stata 14.1 (Stata corp., College Station, TX, USA) for symmetrically distributed continuous variables, and the mean differences were analyzed using the t-test. Where appropriate, the proportions between the groups were evaluated using Fisher's exact or χ2 test. All P value <0.05 were considered statistically significant.

RESULTS

128 responses (29.8%) from the 429 SCCAL members were available for the survey. 39.9% of respondents had a late FGR standardized protocol. Regarding non-severe FGR with normal fetal doppler, 70.8% suggested a fetal doppler study after one week (92/128), 13.8% (18/128) and 6.9% (9/128) proposed the exam, respectively, two and three times for a week. 0.8% (1/128) of respondents had a daily doppler exam, 7.7% (10/128) did not answer, and 3.1% (4/128) repeated the ultrasound exam to time for a week. The antenatal CTG was offered: 70.8% (92/128) of gynaecologists recommended one weekly CTG, whereas 13.8% (18/128) suggested two. 6.9% (9/128) recommended three weekly tests and 0.8% a daily test. 7.7% (10/128) of gynaecologists did not respond. At least, we investigated the gynaecologist's recommendations for outpatient EFW evaluation: 59.4% (76/128) repeated EFW after two weeks, 31.3% (40/128) after one week. 3.9% (4/128) and 3.1 (4/128) recommended EFW after three weeks and twice a week.

CONCLUSIONS

Gynaecologists recommend unnecessary cardiotocography and ultrasound Doppler exams for non-severe late-onset FGR with normal doppler. However, additional studies and comprehensive surveys are needed to support a standardized protocol and assess the feto-maternal outcomes impact.

The association between fetal Doppler and uterine artery blood volume flow in term pregnancies: a pilot study

PURPOSE

To investigate the relationship between uterine artery blood volume flow and fetal Doppler indices in term pregnancies.

MATERIALS AND METHODS

A prospective observational study in a tertiary-care university hospital was performed between December 2021 and May 2022. We included only term pregnancies that received accurate ultrasound scans until a week before the birth. The uterine artery (UtA) diameter and UtA volume blood flow were estimated and recorded. The volume of each artery was summed to obtain the total uterine artery volume blood flow (QUtA). The following fetal Doppler indices were evaluated: Umbilical artery (UA), middle cerebral artery (MCA), ductus venosus (DV), and cerebroplacental ratio (CPR). Linear regression analysis was performed to investigate the relationship between the QUtA and the fetal Doppler indices.

RESULTS

49 pregnancies were included. The UA pulsatility index (PI) analysis showed a significant association with QUtA (r2=0.40, p=0.01), demonstrating a decrease of the UA PI when the QUtA increased. The same relationship was noted between the UtA mean PI and QUtA (r2=0.41, p=0.005). A weak correlation between the newborn weight and the QUtA was also noted (r2=0.31, p=0.048), with an elevated newborn weight when the QUtA was high.

CONCLUSION

This study showed that UA, UtA PI, and birth weight seem to be linked to QUtA. QUtA had an inverse correlation with UA and UtA PI. In addition, increasing the QUtA showed a linear increase in fetal birth weight. These findings could be helpful in high-risk pregnancy management, but additional research is needed to identify how QUtA in the third trimester impacts labor and fetal outcomes.

The effect of maternal position on placental blood flow and fetoplacental oxygenation in late gestation fetal growth restriction: a magnetic resonance imaging study

Fetal growth restriction (FGR) and maternal supine going-to-sleep position are both risk factors for late stillbirth. This study aimed to use magnetic resonance imaging (MRI) to quantify the effect of maternal supine position on maternal-placental and fetoplacental blood flow, placental oxygen transfer and fetal oxygenation in FGR and healthy pregnancies. Twelve women with FGR and 27 women with healthy pregnancies at 34-38 weeks' gestation underwent MRI in both left lateral and supine positions. Phase-contrast MRI and a functional MRI technique (DECIDE) were used to measure blood flow in the maternal internal iliac arteries (IIAs) and umbilical vein (UV), placental oxygen transfer (placental flux), fetal oxygen saturation (FO2 ), and fetal oxygen delivery (delivery flux). The presence of FGR, compared to healthy pregnancies, was associated with a 7.8% lower FO2 (P = 0.02), reduced placental flux, and reduced delivery flux. Maternal supine positioning caused a 3.8% reduction in FO2 (P = 0.001), and significant reductions in total IIA flow, placental flux, UV flow and delivery flux compared to maternal left lateral position. The effect of maternal supine position on fetal oxygen delivery was independent of FGR pregnancy, meaning that supine positioning has an additive effect of reducing fetal oxygenation further in women with FGR, compared to women with appropriately grown for age pregnancies. Meanwhile, the effect of maternal supine positioning on placental oxygen transfer was not independent of the effect of FGR. Therefore, growth-restricted fetuses, which are chronically hypoxaemic, experience a relatively greater decline in oxygen transfer when mothers lie supine in late gestation compared to appropriately growing fetuses. KEY POINTS: Fetal growth restriction (FGR) is the most common risk factor associated with stillbirth, and early recognition and timely delivery is vital to reduce this risk. Maternal supine going-to-sleep position is found to increase the risk of late stillbirth but when combined with having a FGR pregnancy, maternal supine position leads to 15 times greater odds of stillbirth compared to supine sleeping with appropriately grown for age (AGA) pregnancies. Using MRI, this study quantifies the chronic hypoxaemia experienced by growth-restricted fetuses due to 13.5% lower placental oxygen transfer and 26% lower fetal oxygen delivery compared to AGA fetuses. With maternal supine positioning, there is a 23% reduction in maternal-placental blood flow and a further 14% reduction in fetal oxygen delivery for both FGR and AGA pregnancies, but this effect is proportionally greater for growth-restricted fetuses. This knowledge emphasises the importance of avoiding supine positioning in late pregnancy, particularly for vulnerable FGR pregnancies.

Ultrasound evaluation of normal rhesus macaque fetal biometry and uteroplacental hemodynamics

Nonhuman primates are important preclinical models for translational, reproductive, and developmental science. Clinical evaluation of human fetal development is performed using standard sonographic-derived fetal biometry, assessments of amniotic fluid, and uteroplacental hemodynamics. These noninvasive in utero measurements provide important information regarding fetal growth and pregnancy well-being. Abnormalities in fetal growth, amniotic fluid volume, or placental vascular function are associated with placental insufficiency and adverse perinatal outcomes including stillbirth. The fetal biometric parameters most commonly assessed are biparietal diameter, head circumference, abdominal circumference, and femur diaphysis length. Evaluation of amniotic fluid volume includes measuring the fluid in four quadrants of the uterus to generate an Amniotic Fluid Index. Measures of uteroplacental hemodynamics typically include doppler assessment of the umbilical artery and ductus venosus, but can also include interrogation of the uterine artery and umbilical vein. In this study, we compile prenatal ultrasound data of fetal biometry, amniotic fluid measurements, and uteroplacental hemodynamics obtained from pregnancy studies conducted at the Oregon National Primate Research Center. The data included are from control unperturbed pregnant animals who have not undergone in utero experimental manipulations. This is the first report of comprehensive sonographic measurements following standardized clinical obstetric protocols utilized in rhesus macaques. The outcome is a large, prenatal ultrasound resource to be used by laboratory animal researchers in future nonhuman primate pregnancy studies for antenatal assessment.

Comparison of ductus venosus Doppler and cerebroplacental ratio for the prediction of adverse perinatal outcome in high-risk pregnancies before and after 34 weeks

INTRODUCTION

The objective of the study was to compare the accuracy of the ductus venosus pulsatility index (DV PI) with that of the cerebroplacental ratio (CPR) for the prediction of adverse perinatal outcome at two gestational ages: <34 and ≥34 weeks' gestation.

MATERIAL AND METHODS

This was a retrospective study of 169 high-risk pregnancies (72 < 34 and 97 ≥ 34 weeks) that underwent an ultrasound examination of CPR, DV Doppler and estimated fetal weight at 22-40 weeks. The CPR and DV PI were converted into multiples of the median, and the estimated fetal weight into centiles according to local references. Adverse perinatal outcome was defined as a composite of abnormal cardiotocogram, intrapartum pH requiring cesarean delivery, 5' Apgar score <7, neonatal pH <7.10 and admission to neonatal intensive care unit. Values were plotted according to the interval to labor to evaluate progression of abnormal Doppler values, and their accuracy was evaluated at both gestational periods, alone and combined with clinical data, by means of univariable and multivariable models, using the Akaike information criteria (AIC) and the area under the curve (AUC).

RESULTS

Prior to 34 weeks' gestation, DV PI was the latest parameter to become abnormal. However, it was a poor predictor of adverse perinatal outcome (AUC 0.56, 95% CI: 0.40-0.71, AIC 76.2, p > 0.05), and did not improve the predictive accuracy of CPR for adverse perinatal outcome (AUC 0.88, 95% CI: 0.79-0.97, AIC 52.9, p < 0.0001). After 34 weeks' gestation, the chronology of the DV PI and CPR anomalies overlapped, but again DV PI was a poor predictor for adverse perinatal outcome (AUC 0.62, 95% CI: 0.49-0.74, AIC 120.6, p > 0.05), that did not improve the CPR ability to predict adverse perinatal outcome (AUC 0.80, 95% CI: 0.67-0.92, AIC 106.8, p < 0.0001). The predictive accuracy of CPR prior to 34 weeks persisted when the gestational age at delivery was included in the model (AUC 0.91, 95% CI: 0.81-1.00, AIC 46.3, p < 0.0001, versus AUC 0.86, 95% CI: 0.72-1, AIC 56.1, p < 0.0001), and therefore was not determined by prematurity.

CONCLUSIONS

CPR predicts adverse perinatal outcome better than DV PI, regardless of gestational age. Larger prospective studies are needed to delineate the role of ultrasound tools of fetal wellbeing assessment in predicting and preventing adverse perinatal outcome.

Diagnostic Tests in the Prediction of Neonatal Outcome in Early Placental Fetal Growth Restriction

Background and Objectives: Monitoring pregnancies with fetal growth restriction (FGR) presents a challenge, especially concerning the time of delivery in cases of early preterm pregnancies below 32 weeks. The aim of our study was to compare different diagnostic parameters in growth-restricted preterm neonates with and without morbidity/mortality and to determine sensitivity and specificity of diagnostic parameters for monitoring preterm pregnancies with early preterm fetal growth restriction below 32 weeks. Materials and Methods: Our clinical study evaluated 120 cases of early preterm deliveries, with gestational age ≤ 32 + 0 weeks, with prenatally diagnosed placental FGR. All the patients were divided into three groups of 40 cases each based on neonatal condition,: I-Neonates with morbidity/mortality (NMM); II-Neonates without morbidity with acidosis/asphyxia (NAA); III-Neonates without neonatal morbidity/acidosis/asphyxia (NWMAA). Results: Amniotic fluid index (AFI) was lower in NMM, while NWMAA had higher biophysical profile scores (BPS). UA PI was lower in NWMAA. NWMAA had higher MCA PI and CPR and fewer cases with CPR <5th percentile. NMM had higher DV PI, and more often had ductus venosus (DV) PI > 95th‱ or absent/reversed A wave, and pulsatile blood flow in umbilical vein (UV). The incidence of pathological fetal heart rate monitoring (FHRM) was higher in NMM and NAA, although the difference was not statistically significant. ROC calculated by defining a bad outcome as NMM and a good outcome as NAA and NWMAA showed the best sensitivity in DV PIi. ROC calculated by defined bad outcome in NMM and NAA and good outcome in NWMAA showed the best sensitivity in MCA PI. Conclusions: In early fetal growth restriction normal cerebral blood flow strongly predicts good outcomes, while pathological venous blood flow is associated with bad outcomes. In fetal growth restriction before 32 weeks, individualized expectant management remains the best option for the optimal timing of delivery.

Altered Transmission of Cardiac Cycles to Ductus Venosus Blood Flow in Fetal Growth Restriction: Why Ductus Venosus Reflects Fetal Circulatory Changes More Precisely

We aimed to investigate the relation between the time intervals of the flow velocity waveform of ductus venosus (DV-FVW) and cardiac cycles. We defined Delta A as the difference in the time measurements between DV-FVW and cardiac cycles on the assumption that the second peak of ductus venosus (D-wave) starts simultaneously with the opening of the mitral valve (MV). As well, we defined Delta B as the difference of the time measurements between DV-FVW and cardiac cycles on the assumption that the D-wave starts simultaneously with the closure of the aortic valve (AV). We then compared Delta A and Delta B in the control and fetal growth restriction (FGR) groups. In the control group of healthy fetuses, Delta A was strikingly shorter than Delta B. On the other hand, in all FGR cases, no difference was observed. The acceleration of the D-wave is suggested to be generated by the opening of the MV under normal fetal hemodynamics, whereas it precedes the opening of the MV in FGR. Our results indicate that the time interval of DV analysis might be a more informative parameter than the analysis of cardiac cycles.

Doppler Ultrasound of the Umbilical Artery: Clinical Application

OBJECTIVE

 To provide a survey of relevant literature on umbilical artery Doppler ultrasound use in clinical practice, technical considerations and limitations, and future perspectives.

METHODS

 Literature searches were conducted in PubMed and Medline, restricted to articles written in English. Additionally, the references of all analyzed studies were searched to obtain necessary information.

RESULTS

 The use of this technique as a routine surveillance method is only recommended for high-risk pregnancies with impaired placentation. Meta-analyses of randomized trials have established that obstetric management guided by umbilical artery Doppler findings can improve perinatal mortality and morbidity. The values of the indices of Umbilical artery Doppler decrease with advancing gestational age; however, a lack of consensus on reference ranges prevails.

CONCLUSION

 Important clinical decisions are based on the information obtained with umbilical artery Doppler ultrasound. Future efforts in research are imperative to overcome the current limitations of the technique.

Ultrasound prediction of adverse perinatal outcome at diagnosis of late-onset fetal growth restriction

OBJECTIVE

To evaluate the relationship between Doppler and biometric ultrasound parameters measured at diagnosis and perinatal adverse outcome in a cohort of late-onset growth-restricted (FGR) fetuses.

METHODS

This was a multicenter retrospective study of data obtained between 2014 and 2019 including non-anomalous singleton pregnancies complicated by late-onset FGR (≥ 32 weeks), which was defined either as abdominal circumference (AC) or estimated fetal weight (EFW) < 10^th percentile for gestational age or as reduction of the longitudinal growth of AC by over 50 percentiles compared to ultrasound scan performed between 18 and 32 weeks of gestation. We evaluated the association between sonographic findings at diagnosis of FGR and composite adverse perinatal outcome (CAPO), defined as stillbirth or at least two of the following: obstetric intervention due to intrapartum fetal distress, neonatal acidemia, birth weight < 3^rd percentile and transfer to the neonatal intensive care unit (NICU).

RESULTS

Overall, 468 cases with complete biometric and umbilical, fetal middle cerebral and uterine artery (UtA) Doppler data were included, of which 53 (11.3%) had CAPO. On logistic regression analysis, only EFW percentile was associated independently with CAPO (P = 0.01) and NICU admission (P < 0.01), while the mean UtA pulsatility index (PI) multiples of the median (MoM) > 95^th percentile at diagnosis was associated independently with obstetric intervention due to intrapartum fetal distress (P = 0.01). The model including baseline pregnancy characteristics and the EFW percentile was associated with an area under the receiver-operating-characteristics curve of 0.889 (95% CI, 0.813-0.966) for CAPO (P < 0.001). A cut-off value for EFW corresponding to the 3.95^th percentile was found to discriminate between cases with and those without CAPO, yielding a sensitivity of 58.5% (95% CI, 44.1-71.9%), specificity of 69.6% (95% CI, 65.0-74.0%), positive predictive value of 19.8% (95% CI, 13.8-26.8%) and negative predictive value of 92.9% (95% CI, 89.5-95.5%).

CONCLUSIONS

Retrospective data from a large cohort of late-onset FGR fetuses showed that EFW at diagnosis is the only sonographic parameter associated independently with the occurrence of CAPO, while mean UtA-PI MoM > 95^th percentile at diagnosis is associated independently with intrapartum distress leading to obstetric intervention. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Ultrasound Doppler fetal heart rate detection algorithm analyzes the correlation between twin selective fetal growth restriction and cord blood SFass fasL level

Objective

The paper uses ultrasound Doppler fetal heart rate detection algorithm to explore the placental characteristics of monochorionic twin pregnancy with selective fetal growth restriction, and discuss the correlation between selective fetal growth restriction and cord blood SFass FasL level.

Methods

From June 1, 2019 to June 1, 2020 in our hospital, 23 cases of selective fetal growth restriction and 32 cases of uncomplicated cases were included in the monochorionic twin pregnancies whose pregnancy was terminated in our hospital (control group) research. Perfusion was completed within 24 hours after delivery of the placenta. The umbilical arteries and veins of the two fetuses were respectively perfused with four different colors of pigments. The type of anastomoses was judged according to the color of the blood vessels on the placenta surface.

Results

The selective fetal growth restriction group was higher than the control group. In the selective fetal growth restriction group and the control group, the number of anastomoses of the placental superficial arterial artery, arterial vein and venous vein were 1.0 and 1.0, 3.0 and 2.0, 0.0 and 0.0, respectively; the placental superficial arterial artery, arterial vein and venous vein. The total diameters of the anastomosed blood vessels were 2.7 and 2.2, 4.0 and 3.4, 0.0 and 0.0 mm, respectively; the total number of superficial placental anastomosed blood vessels in the selective fetal growth restriction group and the control group were 3.5 and 3.5, respectively.The total diameters were 6.9 and 6.9, respectively 5.9mm.

Conclusion

Uneven placental share and non-central attachment of the umbilical cord may be risk factors for selective fetal growth restriction in monochorionic twin pregnancy.

Examination of fetal well-being evaluation metrics for fetal growth restriction as seen from Japan Obstetric Compensation Cause Analysis Report data

Advances in perinatal care have improved the prognoses of both mothers and neonates; however, cerebral palsy continues to occur. In this study, we examined methods for the intragestational evaluation of the health of infants who later developed cerebral palsy. A retrospective review was conducted on light-for-dates cases among the 2113 cause analysis reports issued by the Japan Obstetric Compensation System between January 2009 and September 2018. In our examination, we determined that non-stress tests and ultrasonic Doppler tests were used to evaluate fetal well-being. Moreover, we observed cases in which additional testing was not performed even when fetal growth restriction (FGR) was identified. Appropriate management of FGR may help reduce the incidence of cerebral palsy.

Time interval analysis of ductus venosus and cardiac cycles in relation with umbilical artery pH at birth in fetal growth restriction

Background

The aims of this study were to evaluate the time intervals of flow velocity waveforms (FVW) of ductus venosus (DV) and cardiac cycles, as well as the pulsatility index of DV-FVW (DV-PI), in correlation with umbilical artery (UA) pH at birth in fetal growth restriction (FGR) complicated with placental insufficiency.

Methods

Data were retrospectively retrieved from pregnancies complicated by FGR. FGR was defined as an estimated fetal weight below − 2.0 S.D. with an elevated UA-PI. Time interval assessments of DV-FVW were as follows: the duration of systolic wave was divided by the duration of diastolic wave and defined as DV-S/D. We also measured the following time intervals of ventricular inflow through tricuspid valve (TV) and mitral valve (MV): (iii), from the second peak of ventricular inflow caused by atrial contraction (A-wave) to the opening of atrio-ventricular valves and: (iv), from the opening of atrio-ventricular valves to the peak of A-wave. (iii)/(iv) was expressed as TV-S/D and MV-S/D, for TV and MV, respectively. The time interval data were transformed into z-scores.

Results

Thirty-one FGR fetuses were included in this study. Both DV-PI and DV-S/D showed significant correlation with UA-pH (r = − 0.677, p = < 0.001 and r = 0.489, p = 0.005 for DV-PI and z-score of DV-S/D, respectively) and more significances were observed in FGR ≤ 28 + 6 gestational weeks (r = − 0.819, p < 0.001 and r = 0.726, p = 0.005, for DV-PI and z-score of DV-S/D, respectively) than in FGR > 28 + 6 gestational weeks (r = − 0.634, p = 0.007 and r = 0.635, p = 0.020, for DV-PI and z-score of DV-S/D, respectively). On the other hand, TV-S/D and MV-S/D showed no significant correlation with UA-pH, although these z-scores indicated significant decreases compared with normal references.

Conclusions

Time interval analysis of DV-FVW might be a valuable parameter, as well as DV-PI, for the antenatal prediction of fetal acidemia in the management of FGR fetuses.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-021-04115-7.

Doppler Ultrasonography of the Fetal Tibial Artery in High-Risk Pregnancy and Its Value in Predicting and Monitoring Fetal Hypoxia in IUGR Fetuses

Background and Objectives: Intrauterine growth restriction (IUGR) is the term used to describe a fetus whose estimated weight is less than the 10th percentile of its age growth curve. IUGR is the second most common cause of perinatal death. In many cases there is a deficiency in the standardization of optimal management, prenatal follow-up and timing of delivery. Doppler examination is the most sensitive test that can assess the condition of the fetus and indicate fetal intrauterine hypoxia. Numerous studies of the fetal intrauterine state focus on the umbilical artery and the fetal cerebral blood vessels, while the peripheral arteries have so far received insufficient attention. Materials and Methods: We present a case of an IUGR fetus monitored with a non-stress test (NST) and a Doppler examination of the fetal arteries (tibial, umbilical, middle cerebral and uterine) and the ductus venosus. In this case the first early sign of fetal hypoxia was revealed by blood flow changes in the tibial artery. Results: We hypothesize that peripheral vascular changes (in the tibial artery) may more accurately reflect the onset of deterioration in the condition of the IUGR fetus, such that peripheral blood flow monitoring ought to be employed along with other techniques already in use. Conclusion: This paper describes the clinical presentation of an early detection of late IUGR hypoxia and claims that blood flow changes in the tibial artery signal the worsening of the fetus’s condition.

Maternal and fetal outcomes of pregnancy in chronic kidney disease: diagnostic challenges, surveillance and treatment throughout the spectrum of kidney disease

Pregnancy requires several physiological adaptations from the maternal organism, including modifications in the glomerular filtration rate and renal excretion of several products. Chronic kidney disease (CKD) can negatively affect these modifications and consequently is associated with several adverse maternal and fetal adverse outcomes (gestational hypertension, progression of renal disease, pre-eclampsia, fetal growth restriction, and preterm delivery). A multidisciplinary vigilance of these pregnancies is essential in order to avoid and/or control the harmful effects associated with this pathology. Dialysis and transplantation can decrease the risks of maternal and fetal complications, nonetheless, the rates of complications remain high comparing with a normal pregnancy. Several recent developments in this area have improved quality and efficacy of treatment of pregnant women with CKD. This article summarizes the most recent literature about CKD and pregnancy.

Doppler abnormalities and perinatal outcomes in pregnant women with early-onset fetal growth restriction

OBJECTIVE

To compare Doppler alterations and perinatal outcomes in pregnant women who evolved with early- and late-onset fetal growth restriction (FGR).

METHODS

A retrospective, observational cohort study with pregnant women who evolved with FGR treated between January 2018 and April 2019, in which all live births from singleton pregnancies, over 24 weeks, with FGR ultrasound diagnosis and under 2700 g weight were included in the study.

RESULTS

Pregnancies with early-onset FGR were more associated with hypertensive disorders (p = .00) and placental vascular insufficiency, resulting in a high degree of umbilical artery Doppler involvement (p = .00) in a short period of pregnancy and higher rates of adverse perinatal outcomes (p = .00). The time of prenatal follow-up of early- and late-onset FGR cases was similar, but the degree of prematurity of the former made the evolution more unfavorable.

CONCLUSION

Early-onset FGR had a lower prevalence but was associated with higher maternal and fetal morbidity and mortality than late-onset FGR.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Monitoring, Delivery and Outcome in Early Onset Fetal Growth Restriction

Early fetal growth restriction (FGR) remains a challenging entity associated with an increased risk of perinatal morbidity and mortality as well as maternal complications. Significant variations in clinical practice have historically characterized the management of early FGR fetuses. Nevertheless, insights into diagnosis and management options have more recently emerged. The aim of this review is to summarize the available evidence on monitoring, delivery and outcome in early-onset FGR.

The ability of various cerebroplacental ratio thresholds to predict adverse neonatal outcomes in term fetuses exhibiting late-onset fetal growth restriction

OBJECTIVES

Our primary aim was to evaluate the ability of various cerebroplacental ratio (CPR) reference values suggested by the Fetal Medicine Foundation to predict adverse neonatal outcomes in term fetuses exhibiting late-onset fetal growth restriction (LOFGR). Our secondary aim was to evaluate the effectiveness of other obstetric Doppler parameters used to assess fetal well-being in terms of predicting adverse neonatal outcomes.

METHODS

This was a retrospective cohort study of 317 pregnant women diagnosed with LOFGR at 37-40 weeks of gestation between January 1, 2016, and September 1, 2019. Receiver operating characteristic (ROC) curves were drawn to determine the predictive performance of CPR <1, CPR <5th or <10th percentile, and umbilical artery pulsatility (PI) >95th percentile in terms of predicting adverse neonatal outcomes.

RESULTS

Pregnant women exhibiting LOFGR who gave birth in our clinic during the study period at a mean of 38 gestational weeks (minimum 37+0; maximum 40+6 weeks); the median CPR was 1.51 [interquartile range (IQR) 1.12-1.95] and median birthweight 2,350 g (IQR 2,125-2,575 g). The CPR <5th percentile best predicted adverse neonatal outcomes [area under the curve (AUC) 0.762, 95% confidence interval (CI) 0.672-0.853, p<0.0001] and CPR <1 was the worst predictor (AUC 0.630, 95% CI 0.515-0.745, p=0.021). Of other Doppler parameters, neither the umbilical artery systole/diastole ratio nor the mid-cerebral artery to peak systolic velocity ratio (MCA-PSV) predicted adverse neonatal outcomes (AUC 0.598, 95% CI 0.480-0.598, p=0.104; AUC 0.521, 95% CI 0.396-0.521, p=0.744 respectively).

CONCLUSIONS

The CPR values below the 5th percentile better predicted adverse neonatal outcomes in pregnancies complicated by LOFGR than the UA PI and CPR <1 by using Fetal Medicine Foundation reference ranges.

Effects of Antenatal Betamethasone on Fetal Doppler Indices and Short Term Fetal Heart Rate Variation in Early Growth Restricted Fetuses

PURPOSE

 To investigate the effects of the antenatal administration of betamethasone on fetal Doppler and short term fetal heart rate variation (CTG-STV) in early growth restricted (FGR) fetuses.

MATERIALS AND METHODS

 Post hoc analysis of data derived from the TRUFFLE study, a prospective, multicenter, randomized management trial of severe early onset FGR. Repeat Doppler and CTG-STV measurements between the last recording within 48 hours before the first dose of betamethasone (baseline value) and for 10 days after were evaluated. Multilevel analysis was performed to analyze the longitudinal course of the umbilico-cerebral ratio (UC ratio), the ductus venosus pulsatility index (DVPIV) and CTG-STV.

RESULTS

 We included 115 fetuses. A significant increase from baseline in CTG-STV was found on day + 1 (p = 0.019) but no difference thereafter. The DVPIV was not significantly different from baseline in any of the 10 days following the first dose of betamethasone (p = 0.167). Multilevel analysis revealed that, over 10 days, the time elapsed from antenatal administration of betamethasone was significantly associated with a decrease in CTG-STV (p = 0.045) and an increase in the DVPIV (p = 0.001) and UC ratio (p < 0.001).

CONCLUSION

 Although steroid administration in early FGR has a minimal effect on increasing CTG-STV one day afterwards, the effects on Doppler parameters were extremely slight with regression coefficients of small magnitude suggesting no clinical significance, and were most likely related to the deterioration with time in FGR. Hence, arterial and venous Doppler assessment of fetal health remains informative following antenatal steroid administration to accelerate fetal lung maturation.

Gestational echobiometry in brachycephalic bitches using high-definition ultrasonography

ABSTRACT: The objective of the present study was to obtain echobiometric values for the most important canine maternal-fetal tissues using high-definition ultrasonography (HDUS) trying to update the formulas for predicting gestational age. Twelve healthy bitches of brachycephalic breeds weighing 7-13kg and aged one to four years were included. The fetuses were analyzed every day using conventional and high-definition ultrasonography from the eighth day after artificial insemination until the day of delivery, using the ACUSON S2000/SIEMENS ultrasound equipment and specific software. Embryonic and fetal structures; diameter of the embryonic vesicle; length of the embryo; biparietal diameter, abdominal length and kidney height; length of the femur, humerus, scapula, radius, and tibia; thickening of the stomach wall; adrenal length; and cardiac size were measured. These variables were correlated with gestational and adjusted tested according to regression models. The results obtained (P<0.001) for: lateral diameter of the gestational sac (R2=81.8%); length of the embryo (R2=85.7%); biparietal (R2=99.1%) and abdominal diameter (R2=97.2%); thickness of the gastric wall (R2=86.9%); length of the femur (R2=96.6%), radius (R2=97.5%), humerus (R2=96.5%), scapula (R2=95.8%) and tibia (R2=97.3%); kidney length (R2=95.8%) and height (R2=96.0%); adrenal length (R2=89.6%); heart length (R2=93.0%) and height (R2=91.5%) of the canine fetuses showed significant correlation with gestational days. This allowed monitoring fetal growth and estimation of age with high accuracy in different gestational periods.

Reference values for ductus venosus flow in normal gestation among an Egyptian population

Background

Doppler studies of the fetal circulation have demonstrated the importance of the ductus venosus in the continuous monitoring of fetuses, especially those of high-risk pregnancies that can lead to abnormal pregnancy outcome. We tried to put reference values for the normal ductus venosus (DV) flow in normal gestation to be used in further studies assessing the different pathologies.

Results

The DV length ranged from 9.8 to 20.9 mm, and the diameter ranged from 0.6 to 2.3 mm. The DV pulsatility index, resistive index, and systolic velocity/maximum velocity during atrial wave ratio declined linearly with increasing of gestational age and were increased after that during the last weeks of pregnancy. Ductus venosus S wave and A wave velocities increased linearly from a mean of 38.30 at the first trimester to 61.68 at the third trimester and from a mean of 11.38 at the first trimester to 30.71 at the third trimester respectively.

Conclusion

A reference range of the normal ductus venosus different Doppler parameters was constructed in a centile module.

Antenatal cardiotocography with and without computer analysis in high-risk pregnancy: a randomized clinical trial

BACKGROUND

Cardiotocography or nonstress test is a technical means of recording the fetal heartbeat and uterine contractions for antenatal monitoring.

OBJECTIVE

This study aimed to evaluate whether antepartum cardiotocography with computer analysis (computerized cardiotocography) increases the incidence of cesarean delivery in women with high-risk pregnancies but without intrauterine growth restriction.

STUDY DESIGN

This was a parallel group nonblinded randomized clinical trial of singletons with high-risk pregnancies admitted for inpatient monitoring between 24 0/7 and 37 6/7 weeks' gestation. Eligible participants were randomly allocated in a 1:1 ratio to antenatal monitoring with either standard cardiotocography or computerized cardiotocography. Women randomized to the computerized cardiotocography arm received cardiotocographic monitoring with computerized analysis in a central monitoring station. The primary outcome was the incidence of cesarean delivery.

RESULTS

Overall, 28 women were enrolled in this trial. In addition, 14 women were randomized to the computerized cardiotocography group and 14 women to the control group. No woman was excluded after randomization or lost to follow-up. Cesarean delivery occurred in 9 women (64.3%) in the computerized cardiotocography group and 9 women (64.3%) in the control group (relative risk, 1.00; 95% confidence interval, 0.21-4.69).There was no significant between-group difference in preterm birth, gestational age at delivery, Apgar score, and birthweight.

CONCLUSION

Among women with high-risk pregnancies, use of computerized cardiotocography for antenatal monitoring did not result in a significant increase in cesarean delivery compared with standard cardiotocography. The results of this single-center randomized trial require confirmation in multicenter studies.

Prenatal prediction of neonatal haemodynamic adaptation after maternal hyperoxygenation

Abstract

The reactivity of the pulmonary vascular bed to the administration of oxygen is well established in the post-natal circulation. The vasoreactivity demonstrated by the fetal pulmonary artery Doppler waveform in response to maternal hyperoxia has been investigated. We sought to investigate the relationship between the reactivity of the fetal pulmonary arteries to hyperoxia and subsequent neonatal cardiac function in the early newborn period.

Methods

This explorative study with convenience sampling measured pulsatility index (PI), resistance index (RI), acceleration time (AT), and ejection time (ET) from the fetal distal branch pulmonary artery (PA) at baseline and following maternal hyperoxygenation (MH). Oxygen was administered for 10 min at a rate of 12 L/min via a partial non-rebreather mask. A neonatal functional echocardiogram was performed within the first 24 h of life to assess ejection fraction (EF), left ventricular output (LVO), and neonatal pulmonary artery AT (nPAAT). This study was conducted in the Rotunda Hospital, Dublin, Ireland.

Results

Forty-six women with a singleton pregnancy greater than or equal to 31 weeks’ gestational age were prospectively recruited to the study. The median gestational age was 35 weeks. There was a decrease in fetal PAPI and PARI following MH and an increase in fetal PAAT, leading to an increase in PA AT:ET. Fetuses that responded to hyperoxygenation were more likely to have a higher LVO (135 ± 25 mL/kg/min vs 111 ± 21 mL/kg/min, p < 0.01) and EF (54 ± 9% vs 47 ± 7%,p = 0.03) in the early newborn period than those that did not respond to MH prenatally. These findings were not dependent on left ventricular size or mitral valve (MV) annular diameter but were related to an increased MV inflow. There was no difference in nPAAT.

Conclusion

These findings indicate a reduction in fetal pulmonary vascular resistance (PVR) and an increase in pulmonary blood flow and left atrial return following MH. The fetal response to hyperoxia reflected an optimal adaptation to postnatal life with rapid reduction in PVR increasing measured cardiac output.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12884-020-03403-y.

Reference values for ductus venosus doppler indices of normal gestation at 22-37 weeks: A Vietnamese cohort study

Prenatal doppler ultrasound of the ductus venosus plays an important role in the evaluation of fetal circulation and fetal heart function. We aimed to establish the percentile of Resistivity Index (RI) and Pulsatility Index (PI) of the Ductus Venosus (DV) among normal Vietnamese fetuses with a gestation from 22 to 37 weeks in a cohort study. Normal Vietnamese fetuses with a gestation ranging from 22 to 37 weeks were examined in a cohort study. The PI and RI were recorded from the DV. We analyzed 640 participants who all fulfilled the inclusion and exclusion criteria of our study. Results: There was a significant correlation between RI, PI and gestational age as shown with the equations y = 0.077x - 0.003x² + 3.493e - 5x³ (r=0.97) and y = 0.106x - 0.004x² + 4.5e - 5x³ (r=0.94), respectively. A centile module was constructed for the DV RI and PI indices among normal Vietnamese fetuses with gestation from 22 to 37 weeks.

Etiology and perinatal outcome of periviable fetal growth restriction associated with structural or genetic anomaly

OBJECTIVE

To investigate the etiology and perinatal outcome of periviable fetal growth restriction (FGR) associated with a structural defect or genetic anomaly.

METHODS

This was a retrospective study of singleton pregnancies seen at a referral fetal medicine unit between 2005 and 2018, in which FGR (defined as fetal abdominal circumference ≤ 3^rd percentile for gestational age) was diagnosed between 22 + 0 and 25 + 6 weeks of gestation. The study group included pregnancies with periviable FGR associated with a genetic or structural anomaly (anomalous FGR), while the control group consisted of structurally and genetically normal pregnancies with periviable FGR (non-anomalous FGR). Results of genetic testing, TORCH screen and postmortem examination, as well as perinatal outcome, were investigated.

RESULTS

Of 255 pregnancies complicated by periviable FGR, 188 were eligible; of which 52 (28%) had anomalous FGR and 136 (72%) had non-anomalous FGR. A confirmed genetic abnormality accounted for 17/52 cases (33%) of anomalous FGR, with trisomy 18 constituting over 50% (9/17; 53%). The most common structural defects associated with FGR were central nervous system abnormalities (13/35; 37%). Overall, 12 (23%) cases of anomalous FGR survived the neonatal period. No differences were found in terms of perinatal survival between pregnancies with anomalous and those with non-anomalous FGR.

CONCLUSIONS

Most pregnancies complicated by anomalous FGR were associated with a structural defect. The presence of an associated genetic defect was invariably lethal, while those with a structural defect, in the absence of a confirmed genetic abnormality, survived into infancy in over 90% of cases, with an overall one in three chance of perinatal survival. These data can be used for counseling prospective parents. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

The value of fetal Doppler indices as predictors of perinatal outcome in women with preeclampsia with severe features

Objective: To evaluate the diagnostic performance of Doppler sonography of umbilical artery (UA), fetal middle cerebral artery (MCA), ductus venosus (DV) & umbilical vein (UV) for prediction of adverse perinatal outcome.Material and Methods: A prospective cohort study conducted on 60 women diagnosed  with preeclampsia with severe features divided into two groups based on adverse perinatal outcome.Results: Statistically Significant differences were demonstrated UA PI (1.28 ± 0.23 vs. 0.96 ± 0.21, P <0.001), UA RI (0.78 ± 0.09 vs. 0.62 ± 0.09, P <0.001), MCA PI (1.27 ± 0.28 vs. 1.45±0.20, P 0.005), MCA RI (0.67 ± 0.10 vs. 0.76 ± 0.08, P<0.001), Cerebroplacental ratio (1.01 ± 0.36 vs. 1.57 ± 0.35, P <0.001), DV PVIV (0.67 ± 0.20 vs. 0.51 ± 0.14, P= 0.004), DV PSV (54.74 ± 17.11 vs. 42.15 ± 9.42, P= 0.004)  and abnormal DV a wave (23.8 vs. 0%, P = 0.004) in women with adverse and normal perinatal outcome respectively. UA PI and CPR had the highest specificity while UA RI had the highest sensitivity for detection of adverse perinatal outcome.Conclusion: CPR < 1 can be used to identify fetuses at risk of morbidity and mortality among such cases.

Are maternal hemodynamic indices markers of fetal growth restriction in pregnancies with a small-for-gestational-age fetus?

OBJECTIVE

Pregnancies complicated by fetal growth restriction (FGR) have a worse outcome than those with a small-for-gestational-age (SGA) fetus. There is increasing evidence of a maternal cardiovascular role in the pathophysiology of FGR. We aimed to compare maternal hemodynamic indices between pregnancies complicated by FGR and those delivering a SGA neonate, using a non-invasive device.

METHODS

This was a prospective study of normotensive pregnancies complicated by FGR (defined as estimated fetal weight (EFW) < 3^rd centile or Doppler evidence of impaired placental-fetal blood flow), those with a SGA fetus (defined as EFW < 10^th centile) and control pregnancies with an appropriately grown fetus. Assessment of maternal hemodynamics (heart rate (HR), cardiac output (CO), mean arterial pressure (MAP), systemic vascular resistance (SVR) and stroke volume) was performed using a non-invasive device (USCOM-1A®). Uterine artery (UtA) pulsatility index (PI) was measured using transabdominal ultrasound. Hemodynamic variables that are affected by gestational age and maternal characteristics were corrected for using device-specific reference ranges. Comparison between groups was performed using the chi-square test or the Mann-Whitney U-test, as appropriate.

RESULTS

A total of 102 FGR, 64 SGA and 401 control pregnancies, with a median gestational age of 36 weeks, were included in the analysis. Women with a pregnancy complicated by FGR and those with a SGA fetus were shorter and weighed less than did controls. Compared with controls, the FGR group had significantly lower median maternal HR (80 beats per min (bpm) vs 85 bpm; P = 0.001) and CO multiples of the median (MoM; 0.91 vs 0.98; P = 0.003), and higher median maternal MAP (90 mmHg vs 87 mmHg; P = 0.040), SVR MoM (1.2 vs 1.0; P < 0.001) and UtA-PI MoM (1.1 vs 0.96; P < 0.001), but there was no significant difference in stroke volume MoM (1.0 vs 0.98; P = 0.647). Compared with the SGA group, the FGR group had a significantly lower median HR (80 bpm vs 87 bpm; P = 0.022), and higher median maternal MAP (90 mmHg vs 85 mmHg; P = 0.025), SVR MoM (1.2 vs 1.0; P = 0.002) and UtA-PI MoM (1.1 vs 0.98; P = 0.005), but there was no significant difference in CO MoM (0.91 vs 0.96; P = 0.092) or stroke volume MoM (1.0 vs 1.0; P = 0.806). There were no significant differences in adjusted maternal hemodynamic indices between the SGA group and controls.

CONCLUSION

Pregnancies complicated by FGR presented with impaired maternal hemodynamic function, as evidenced by lower HR and CO, as well as higher MAP, SVR and UtA resistance. Pregnancies delivering a SGA neonate, without evidence of FGR, had normal maternal hemodynamic function. Maternal hemodynamic indices may therefore be of value in distinguishing FGR from SGA pregnancies. Copyright © 2019 ISUOG. Published by John Wiley & Sons Ltd.

Ductus venosus Doppler waveform pattern in fetuses with early growth restriction

INTRODUCTION

We aimed to assess if maximum velocities of the ductus venosus flow velocity waveform are associated with adverse outcomes in early-onset fetal growth restriction.

MATERIAL AND METHODS

Retrospective cohort study from two tertiary referral units, including singleton fetuses with estimated birthweight or fetal abdominal circumference ≤10th centile and absent or reversed end-diastolic velocity in the umbilical artery delivered between 26⁺⁰ and 34⁺⁰  weeks of gestation. Pulsatility index for veins, and maximum velocities of S-, D-, v- and a-waves, were measured in the ductus venosus within 24 hours of birth. Logistic regression was used to describe the relation between severe neonatal morbidity or neonatal death and clinical independent predictors.

RESULTS

The study population included 132 early-onset fetal growth restriction fetuses. Newborns with neonatal morbidity or neonatal death had significantly lower values of v/D maximum velocity ratio multiples of the median (0.86 vs 095; P = 0.006) within 24 hours of birth. The v/D ratio remained a significant predictor of neonatal death or severe neonatal morbidity after adjusting for gestational age and birthweight (adjusted odds ratio 0.065, 95% confidence interval 0.004-0.957).

CONCLUSIONS

Assessment of ductus venosus v/D maximum velocity ratio might help to identify fetal growth restriction fetuses at increased risk for neonatal death or severe neonatal morbidity. Confirmation in prospective studies is necessary.

Longitudinal Doppler references for monochorionic twins and comparison with singletons

OBJECTIVES

To construct monochorionic (MC) twin-specific longitudinal Doppler references for umbilical artery pulsatility index (UA-PI), middle cerebral artery (MCA) PI and peak systolic velocity (PSV) and ductus venosus (DV) PI derived from a strictly selected cohort of uncomplicated MC twins. The secondary aim of the study was to compare our findings with singleton reference charts.

METHODS

A retrospective evaluation was made of all consecutive uncomplicated MC twin pregnancies referred to our Unit from 2010 to 2018. Fortnightly serial examinations were performed of UA-PI, MCA-PI, MCA-PSV and DV-PI, according with the clinical protocol, from 20 to 37 weeks of gestation. We included cases with at least four ultrasound examinations, delivery at our hospital and complete neonatal follow up. A two-step method was used to trace the estimated centile curves: estimation of the median was performed with appropriate fractional polynomials by a multilevel model and estimation of the external centiles through the residuals (quantile regression). The comparison with singletons was made by plotting the references derived from the present study on the referred charts commonly used for singletons.

RESULTS

The study group comprised 150 uncomplicated MC twin pairs. Estimated centiles (3rd, 5th, 10th, 50th, 90th, 95th, 97th) of UA-PI, MCA-PI, MCA-PSV and DV-PI in function of the gestational age are presented. The comparison with singletons showed substantial differences, with higher UA-PI and lower MCA-PI and PSV median values in MC twins. Median DV PI values were similar to the values for singletons, while the upper centiles were higher in MC twins.

CONCLUSIONS

This study sets out MC twin-specific longitudinal references for UA-PI, MCA-PI, MCA-PSV and DV-PI derived from the largest series of uncomplicated MC twin pregnancies presently available. The comparison with singleton reference values underscores the deviation from physiology that is intrinsic to these unique pregnancies and supports the need for MC twin-specific charts.

Recurrent intrauterine growth restriction: characteristic placental histopathological features and association with prenatal vascular Doppler

PURPOSE

Intrauterine growth restriction (IUGR) is a leading cause of perinatal morbidity and mortality, carrying a 20% recurrence rate. The placental disease is a cardinal factor among IUGR underlying processes. This study describes placental histopathological features (HPf) characteristic of recurrent IUGR (rIUGR) and assesses association with antenatal Doppler studies.

METHODS

We conducted a retrospective case-control study, between the years 2005-2016, evaluating 34 placentae of 17 women with rIUGR, and 59 placentae of a gestational age-matched control. Doppler studies within a week prior to delivery were analyzed for the rIUGR group.

RESULTS

Placental HPf characteristic of rIUGR is maternal and fetal vascular malperfusion lesions; maternal accelerated villous maturation and villous infarcts, repetitive feature rate 88.8% (95% CI 37.2-97), and fetal chorionic plate/stem villous thrombi, repetitive feature rate 66.6% (95% CI 30-90.3). Among women with abnormal Doppler, 83.3% had a placenta HPf of maternal vascular malperfusion lesions and 66.7% presented with a hypertensive disorder.

CONCLUSIONS

Women with rIUGR are a unique group of patients characterized by repetitive placental HPf of both maternal and fetal vascular malperfusion lesions. Specifically, maternal vascular malperfusion lesions are associated with abnormal Doppler findings. In conclusion, characteristic placental HPf may serve as predictors of future IUGR recurrence, thus offering early recognition of pregnancies that require "high-risk" antenatal care.

Fetal autonomic malfunction as a marker of fetal distress in growth-restricted fetuses: three case reports

Fetal growth restriction (FGR) is characterized by fetal compromise and delayed neurological maturation. We report 3 cases of early FGR in the 26th week of gestation, based on hemodynamic Doppler monitoring, conventional cardiotocography, and non-invasive fetal electrocardiography (NI-FECG). Fetal heart rate variability (HRV), beat-to-beat variations, and fetal autonomic brain age scores (fABASs) were normal despite the absence of umbilical diastolic flow in the first case and the pregnancy continued to 30 weeks. NI-FECG helped achieve better fetal maturity. Fetal HRV and fABASs were low in the second and third cases. Fetal demise occurred soon in both cases. We conclude that NI-FECG could be a prospective method for the detection of fetal distress in early FGR.

Clinical Significance of Ductus Venosus Waveform as Generated by Pressure- volume Changes in the Fetal Heart

The ductus venosus is a vascular shunt situated within the fetal liver parenchyma, connecting the umbilical vein to the inferior vena cava. This vessel acts as a bypass of the liver microcirculation and plays a critical role in the fetal circulation. The ductus venosus allows oxygenated and nutrient-rich venous blood to flow from the placenta to the myocardium and brain. Increased impedance to flow in the fetal ductus venosus is associated with fetal aneuploidies, cardiac defects and other adverse pregnancy outcomes. This review serves to improve our understanding of the mechanisms that regulate the blood flow redistribution between the fetal liver circulation and fetal heart and the clinical significance of the ductus venosus waveform as generated by pressure-volume changes in the fetal heart.

Threshold of metabolic acidosis associated with newborn cerebral palsy: medical legal implications

Obstetricians and gynecologists belong to 1 of the medical specialties with the highest rate of litigation claims. Among birth injury cases, those cases with cerebral palsy outcomes account for litigation settlements or judgments often in the millions of dollars. In cases of potential perinatal asphyxia, a threshold level of metabolic acidosis (base deficit ≥12 mmol/L) is necessary to attribute neonatal encephalopathy to an intrapartum hypoxic event. With increasing duration or severity of a hypoxic stress resulting in metabolic acidosis, newborn infant umbilical artery base deficit increases. It may be alleged that, as base deficit levels increase beyond 12 mmol/L, there is an increased likelihood and severity of cerebral palsy. As a corollary, it may be claimed that an earlier delivery (by minutes) would reduce the base deficit and prevent or reduce the severity of cerebral palsy. This issue is of relevance to obstetricians as defendants, because retrospective "expert" analysis of cases may suggest that optimal management decisions would have resulted in an earlier delivery. In addressing the association of metabolic acidosis and cerebral palsy, base deficit should be measured as the extracellular component (base deficit_{extracellular fluid}) rather than the commonly used base deficit_blood. Studies suggest that, beyond the base deficit threshold of 12 mmol/L, the incidence and severity of cerebral palsy does not significantly increase (until ≥20 mmol/L), although the risk of neonatal death rises markedly. Thus, among most infants with hypoxia-associated neonatal encephalopathy, the occurrence of cerebral palsy is unlikely to be impacted by delivery time variation of few minutes, and this argument should not serve as the basis for medical legal claims.

Uterine and fetal placental Doppler indices are associated with maternal cardiovascular function

BACKGROUND

The mechanism underlying fetal-placental Doppler index changes in preeclampsia and/or fetal growth restriction are unknown, although both are associated with maternal cardiovascular dysfunction.

OBJECTIVE

We sought to investigate whether there was a relationship between maternal cardiac output and vascular resistance and fetoplacental Doppler findings in healthy and complicated pregnancy.

STUDY DESIGN

Women with healthy pregnancies (n=62), preeclamptic pregnancies (n=13), preeclamptic pregnancies with fetal growth restriction (n=15), or fetal growth restricted pregnancies (n=17) from 24-40 weeks gestation were included. All of them underwent measurement of cardiac output with the use of an inert gas rebreathing technique and derivation of peripheral vascular resistance. Uterine and fetal Doppler indices were recorded; the latter were z scored to account for gestation. Associations were determined by polynomial regression analyses.

RESULTS

Mean uterine artery pulsatility index was higher in fetal growth restriction (1.37; P=.026) and preeclampsia+fetal growth restriction (1.63; P=.001) but not preeclampsia (0.92; P=1) compared with control subjects (0.8). There was a negative relationship between uterine pulsatility index and cardiac output (r²=0.101; P=.025) and umbilical pulsatility index z score and cardiac output (r²=0.078; P=.0015), and there were positive associations between uterine pulsatility index and peripheral vascular resistance (r²=0.150; P=.003) and umbilical pulsatility index z score and peripheral vascular resistance (r²= 0.145; P=.001). There was no significant relationship between cardiac output and peripheral vascular resistance with cerebral Doppler indices.

CONCLUSION

Uterine artery Doppler change is abnormally elevated in fetal growth restriction with and without preeclampsia, but not in preeclampsia, which may explain the limited sensitivity of uterine artery Doppler changes for all these complications when considered in aggregate. Furthermore, impedance within fetoplacental arterial vessels is at least, in part, associated with maternal cardiovascular function. This relationship may have important implications for fetal surveillance and would inform therapeutic options in those pathologic pregnancy conditions currently, and perhaps erroneously, attributed purely to placental maldevelopment. Uterine and fetal placental Doppler indices are associated significantly with maternal cardiovascular function. The classic description of uterine and fetal Doppler changes being initiated by placental maldevelopment is a less plausible explanation for the pathogenesis of the conditions than that relating to maternal cardiovascular changes.

Understanding Fetal Heart Rate Patterns That May Predict Antenatal and Intrapartum Neural Injury

Electronic fetal heart rate (FHR) monitoring is widely used to assess fetal well-being throughout pregnancy and labor. Both antenatal and intrapartum FHR monitoring are associated with a high negative predictive value and a very poor positive predictive value. This in part reflects the physiological resilience of the healthy fetus and the remarkable effectiveness of fetal adaptations to even severe challenges. In this way, the majority of "abnormal" FHR patterns in fact reflect a fetus' appropriate adaptive responses to adverse in utero conditions. Understanding the physiology of these adaptations, how they are reflected in the FHR trace and in what conditions they can fail is therefore critical to appreciating both the potential uses and limitations of electronic FHR monitoring.