Measurement of placental bed vascularization in the first trimester, using 3D-power-Doppler, for the detection of pregnancies at-risk for fetal and maternal complications

Ultrasonographic placental parameters at 11-13+6 weeks' gestation in the prediction of complications in pregnancy after assisted reproductive technology

OBJECTIVE

To evaluate the performance of maternal factors, biophysical and biochemical markers at 11-13 + 6 weeks' gestation in the prediction of gestational diabetes mellitus with or without large for gestational age (GDM ± LGA) fetus and great obstetrical syndromes (GOS) among singleton pregnancy following in-vitro fertilisation (IVF)/embryo transfer (ET).

MATERIALS AND METHODS

A prospective cohort study was conducted between December 2017 and January 2020 including patients who underwent IVF/ET. Maternal mean arterial pressure (MAP), ultrasound markers including placental volume, vascularisation index (VI), flow index (FI) and vascularisation flow index (VFI), mean uterine artery pulsatility index (mUtPI) and biochemical markers including placental growth factor (PlGF) and soluble fms-like tyrosine kinase-1 (sFlt-1) were measured at 11-13 + 6 weeks' gestation. Logistic regression analysis was performed to determine the significant predictors of complications.

RESULTS

Among 123 included pregnancies, 38 (30.9%) had GDM ± LGA fetus and 28 (22.8%) had GOS. The median maternal height and body mass index were significantly higher in women with GDM ± LGA fetus. Multivariate logistic regression analysis demonstrated that in the prediction of GDM ± LGA fetus and GOS, there were significant independent contributions from FI MoM (area under curve (AUROC) of 0.610, 95% CI 0.492-0.727; p = 0.062) and MAP MoM (AUROC of 0.645, 95% CI 0.510-0.779; p = 0.026), respectively.

CONCLUSION

FI and MAP are independent predictors for GDM ± LGA fetus and GOS, respectively. However, they have low predictive value. There is a need to identify more specific novel biomarkers in differentiating IVF/ET pregnancies that are at a higher risk of developing complications.

Umbilical Vein Pulse Wave Spectral Analysis: A Possible Method for Placental Assessment Through Evaluation of Maternal and Fetal Flow Components

OBJECTIVES

Placental blood flow analysis is complicated by having both maternal and fetal flow components. Using the Fast Fourier Transform (FFT) of the umbilical venous pulse wave spectra (PW) envelope, we could simultaneously assess maternal/fetal blood flow in the placenta and investigate if normal and intrauterine growth restriction (IUGR)/pre-eclamptic pregnancies could be distinguished.

METHODS

This retrospective study included normal gestations (N = 11) and gestations with IUGR, pre-eclampsia, or both (N = 13). Umbilical vein PW were acquired and spectral envelopes were identified as a function of time and analyzed by FFT. Base-10 logarithms of the ratios of the maternal/fetal spectral peaks (LRSP) were compared in normal and IUGR/pre-eclamptic populations (two-tailed t-test). Body mass index (BMI), gestational age at scan time, placental position, and weight-normalized umbilical vein blood volume flow (two-tailed t-test, analysis of variance [ANOVA] analysis) were tested. P < .05 was considered significant.

RESULTS

The LRSP for normal and IUGR/pre-eclamptic pregnancies were 0.141 ± 0.180 and -0.072 ± 0.262 (mean ± standard deviation), respectively (P = .033). We detected differences between normal gestations and combinations of LRSP and weight-normalized umbilical venous blood flows. Placental effects based on LRSPs and blood flow may act synergistically in cases with both pre-eclampsia and IUGR (P = .014). No other significant associations were seen.

CONCLUSIONS

In this preliminary study, we showed that umbilical venous flow contains markers related to placental maternal/fetal blood flow, which can be used to assess IUGR and pre-eclampsia. When coupled with umbilical cord blood flow, this new marker may potentially identify the primary causes of the two conditions.

Evaluation of placental growth potential and placental bed perfusion by 3D ultrasound for early second-trimester prediction of preeclampsia

PURPOSE

This study aimed to investigate whether placental parameters measured by three-dimensional ultrasound are associated with preeclampsia (PE) and small-for-gestational-age (SGA).

METHODS

In total, 1163 pregnancies at 11-14 weeks of gestation were recruited between October 8, 2020, and April 30, 2021. Placenta volume (PV), placental bed vascularization flow index (PBVFI), and uterine arteries pulse index (UtA-PI) were measured. Placental quotient (PQ = PV/weeks of gestation) was calculated. All participants were re-examined 4 weeks later. The placental volume growth rate (PVGR = placental volume difference between the two examinations/interval days) was also calculated. Patients were divided into four groups by the gestational age at the onset of PE and birth weight: early-onset PE (E-PE, n = 18), late-onset PE (L-PE, n = 36), isolated SGA5 (birth weight less than the fifth percentile for gestational age without PE, n = 9), and unaffected (n = 1100) groups.

RESULTS

A predictive model for E-PE was established, which consisted of unnatural conception, chronic hypertension, PBVFI (of second examination), and PVGR for E-PE; 94.4% sensitivity and 96.7% specificity by receiver operating characteristic curve analysis.

CONCLUSIONS

Overall, decreased placental growth potential and low placental bed perfusion in the early second trimester have potential in predicting E-PE.

New insights into human functional ultrasound imaging

Ultrasound imaging is a vital tool for exploring in vivo the placental function which is essential to understand pathological phenomena such as preeclampsia or intrauterine growth restriction. As technology advances including ready availability of three-dimensional (3D) probes and novel software, new markers of placental function become possible. The objective of this review was to provide an overview of the new ultrasound markers of placental function with a focus on the potential clinical application of three-dimensional power Doppler (3DPD). A broad-free text literature search was undertaken based on human placental studies and sixty full-text studies were included in this review. Three-dimensional power Doppler is a promising technique to predict preeclampsia in the first trimester. However, the influence of external factors such as body mass index, parameter standardisation and machine settings still need to be addressed. Contrast-enhanced ultrasound is currently reserved for research, because the required injected contrast mediums are not currently approved for use in pregnancy, although the safety data is reassuring.

Investigation Into the Predictive Potential of Three-Dimensional Ultrasonographic Placental Volume and Vascular Indices in Gestational Diabetes Mellitus

BACKGROUND

The use of ultrasonography in pregnancies complicated with gestational diabetes mellitus (GDM) can vary according to clinical practice. This study aims to compare the changes of placental volume (PV) and vascular indices measured by three-dimensional (3D) Power Doppler between pregnant women with and without GDM.

MATERIALS AND METHODS

This was a prospective study of singleton pregnancies who took the early nuchal translucency examination from January 2018 to September 2019. Data on PV and vascular indices including vascularization index (VI), flow index (FI), and vascularization flow index (VFI) between pregnant women with and without GDM were measured by 3D Power Doppler ultrasound machine. Univariate and multivariate logistic regression determined the association between risk factors and GDM. Receiver operating characteristic (ROC) and area under the ROC curve (AUC) were applied to evaluate the diagnostic value of different parameters for GDM.

RESULTS

Of the 141 pregnant women enrolled, 35 developed GDM and 106 did not. The maternal age and gravida in the GDM group were significantly higher than that in the non-GDM group. The PV, VI, FI, and VFI in the GDM group were significantly lower than that in the non-GDM group. There were no significant differences in other clinical parameters between the two groups. After adjustments in multivariate logistic regression analysis, significant differences were observed in VI [odds ratio (OR) = 0.98, 95% confidence interval (CI) = 0.951-1.002], FI (OR = 0.93, 955 CI: 0.86-1.00), and VFI (OR = 0.67, 95% CI = 0.52-0.87). ROC analysis indicated that the combination of maternal age, gravida, PV, and VFI was more accurate as a marker for detecting GDM than the PV, VI, FI, or VFI alone.

CONCLUSIONS

The 3D ultrasonography results suggest that PV and vascular indices (VI, FI, and VFI) during the first trimester may serve as potential markers for GDM diagnosis. The combination of maternal age, gravida, and sonographic markers may have good diagnostic values for GDM, which should be confirmed by further investigations.

First trimester screening for pre-eclampsia and intrauterine growth restriction using three-dimensional Doppler angiography (SPIRIT): protocol for a multicentre prospective study in nulliparous pregnant women

INTRODUCTION

Pre-eclampsia (PE) and intrauterine growth restriction (IUGR) are two major pregnancy complications, related to chronic uteroplacental hypoperfusion. Nowadays, there is no screening or diagnostic test for uteroplacental vascularisation deficiency in pregnant women. Since 2004, 3 three-imensional power Doppler (3DPD) angiography has been used for the evaluation of uteroplacental vascularisation and three vascular indices are usually calculated: Vascularisation Index (VI), Flow Index (FI) and vascularisation-FI (VFI). A high intraobserver and interobserver reproducibility and a potential interest for placental function study were reported by our team and others.The main objective of our study is to determine differences in 3DPD indices at first trimester between pregnancies defined at their outcome as uncomplicated pregnancy, PE (mild and severe) and IUGR in nulliparous women.

METHODS AND ANALYSIS

This is a national multicentre prospective cohort study conducted in four French maternity units. We expect to include 2200 women in a period of 36 months. The nulliparous pregnant women will be recruited during their first trimester consultation (11-13+6 gestation week (GW)).The 3DPD and uterine artery Doppler acquisition will be included in the current routine 11-13+6 GW ultrasound. Also, additional blood samples will be taken for biomarker analysis (PAPP-A and P1GF) and biological collection. Uteroplacental VIs (FI and VFI) will be measured. For each subgroup (uncomplicated pregnancy, PE and IUGR), mean values in 3DPD indices will be computed and compared using a pairwise t test with a Bonferroni correction p value adjustment.

ETHICS AND DISSEMINATION

The study was approved by the French Ethics Committee, the Comité de Protection des Personnes SUD MEDITERRANEE IV on 13 February 2018 with reference number 17 12 03. The results of this study will be published in a peer-reviewed journal and will be presented at relevant conferences.

TRIAL REGISTRATION NUMBER

NCT03342014; Pre-results. PHRCN-16-0567.

Placental vascularization indices and prediction of pre-eclampsia in high-risk women

OBJECTIVE

To assess ability of first and second trimester Placental Vascularization Indices (PVIs) to predict pre-eclampsia (PE) in high-risk pregnancies.

METHOD

PVIs derived from 3-Dimensional power Doppler imaging were measured at 11+0-13 + 6 (n = 194) and 19+0-21 + 6 weeks (n = 195). Logistic regression (LR) models used PE as the outcome. To quantify added value of PVIs to baseline characteristics in predicting PE, integrated discrimination improvement (IDI) and net reclassification improvement (NRI) indices were calculated.

RESULTS

Overall rate of PE was 12% (n = 26). Lower first trimester PVIs were seen in women with PE (mean, SD); Vascularization Index (VI,%): 10.0 (6.2) v 14.7 (7.6), P = 0.005, Flow Index (FI): 37.7 (9.1) v 42.9 (10.4), P = 0.03, Vascularization Flow Index (VFI): 3.8 (2.5) v 6.6 (4.0), P < 0.001). All first trimester PVIs predicted PE in LR models adjusted for covariates. IDI and NRI analyses confirmed added clinical utility of VI (IDI 0.05, P = 0.004; NRI 0.66, P < 0.001) and VFI (IDI 0.06, P = 0.004; NRI 0.53, P = 0.91). In the second trimester, FI was lower in women with PE (39.6 (9.1) v 44.4 (8.6), P = 0.01) and predicted PE in adjusted LR models (standardised OR 0.53, 95% CI 0.29-0.97, P = 0.04). FI discriminated between cases and non-cases of PE (IDI 0.04, P = 0.04).

CONCLUSION

First trimester placental vascularization indices (VI, FI and VFI) have the potential to predict PE in high-risk pregnancies, with FI remaining predictive in the second trimester.

Comparison of placental three-dimensional power Doppler indices and volume in the first and the second trimesters of pregnancy complicated by gestational diabetes mellitus

Objective: To compare the changes of placental three-dimensional power Doppler indices and volume in the first and the second trimesters of pregnancy with gestational diabetes mellitus (GDM). Methods: This was a prospective case-control study of singleton pregnancies with risk factors for GDM. Data on placental vascular indices including vascularization index (VI), flow index (FI), and vascularization flow index (VFI), as well as placental volume were obtained and analyzed during the first and the second trimesters between pregnant women with and without GDM. Results: Of the 155 pregnant women enrolled, 31 developed GDM and 124 did not. VI and VFI were significantly lower in the GDM group during the first and second trimesters (VI: p = .023, and VFI: p = .014 in the first trimester; VI: p = .049, and VFI: p = .031 in the second trimester). However, the placental volume was similar in both the groups during the first trimester, while it was significantly increased in the GDM group during the second trimester (p = .022). There were no significant differences in FI and uterine artery pulsatility index between the two groups. After adjustments in multivariate logistic regression analysis, significant differences were observed in the first trimester VFI (adjusted odds ratio (OR) 0.76, 95% confidence interval (CI) 0.61-0.93), second trimester VFI (adjusted or 0.83, 95%CI 0.71-0.96), and second trimester placental volume (adjusted or 1.03, 95%CI 1.01-1.05). Conclusions: Placental vascular indices can provide an insight into placental vascularization in GDM during early pregnancy. VFI rather than placental volume may be a sensitive sonographic marker in the first trimester of GDM placentas.

First trimester placental vascularization and angiogenetic factors are associated with adverse pregnancy outcome

BACKGROUND

Hypertensive disorders, fetal growth restriction and preterm birth are major obstetrical complications and are related to impaired placentation. Early identification of impaired placentation can advance clinical care by preventing or postpone adverse pregnancy outcome.

OBJECTIVES

Determine whether sonographic assessed placental vascular development and concomitant changes in inflammation- and/or angiogenesis-related serumproteins differ in the first trimester between uncomplicated pregnancies and pregnancies with adverse outcome.

STUDY DESIGN

This prospective longitudinal study defines adverse pregnancy outcome as conditions associated with impaired placentation; fetal growth restriction, hypertensive disorder, preterm birth and placental abruption. The vascularization index, flow index, vascularization flow index and placental volume were determined at 8, 10 and 12 weeks pregnancy from 64 women using 3D power Doppler. Serum levels were analyzed for Angiopoetin-1 and -2, Leptin, VEGF-R, VEGF, and EGF.

RESULTS

The vascularization index and vascular flow index increased in uneventful pregnancies with almost 50% between 8 and 12 weeks, resulting in a ∼50% higher vascularization index at 12 weeks compared to women with an adverse pregnancy outcome. Women with an adverse pregnancy outcome (n = 13) had significantly lower indices and placental volumes at all time points measured and these indices did not increase between 8 and 12 weeks. Reduced vascular development was associated with increased Angiopoietin-1 levels at 8 and 12 weeks and increased Leptin levels at 8 weeks.

CONCLUSIONS

Pregnancies with an adverse outcome caused by conditions associated with impaired placentation differ from uneventful pregnancies in having reduced placental vascularization accompanied by elevated circulating levels of Angiopoietin-1 and Leptin already in the first trimester.

Mode of conception does not affect fetal or placental growth parameters or ratios in early gestation or at delivery

PURPOSE

Ratio of fetal weight to placenta size varies by mode of conception (fertility treatments utilized) in animals. Our objective was to assess whether fertility treatments also affect these ratios in humans.

METHODS

In this retrospective study, we assessed two cohorts: (a) early gestation cohort, women with singleton pregnancies who underwent first trimester vaginal ultrasound and (b) delivered cohort, women who delivered a live-born, singleton infant with placenta disposition to pathology. Crown rump length (CRL) and estimated placental volume (EPV) were calculated from first trimester ultrasound images using a validated computation. Infant birth weight (BW), pregnancy data, placental weight (PW), and placental histopathology were collected. Fetal growth-to-placental weight ratios (CRL/EPV; BW/PW) and placentas were compared by mode of conception. Linear regression was used to adjust for confounding variables.

RESULTS

Two thousand one hundred seventy patients were included in the early gestation cohort and 1443 in the delivered cohort. Of the early gestation cohort (a), 85.4% were spontaneous conceptions, 5.9% Non-IVF Fertility (NIFT), and 8.7% IVF. In the delivered cohort (b), 92.4% were spontaneous, 2.1% NIFT, and 80 5.5% IVF. There were no significant differences between fetal growth-to-placental weight parameters, ratios, and neonatal birth measurements based on mode of conception. Placenta accreta was significantly higher in the patients receiving fertility treatments (1.2 versus 3.6%, p < 0.05).

CONCLUSIONS

Mode of conception does not appear to influence fetal growth-to-placental weight ratios throughout gestation. In addition, findings in animal models may not always translate into human studies of infertility treatment outcomes.

Maternal plasma n-3 and n-6 polyunsaturated fatty acids during pregnancy and features of fetal health: Fetal growth velocity, birth weight and duration of pregnancy

BACKGROUND & AIMS

Maternal fatty acids are essential for fetal growth and development. Here, we examine associations between maternal mid-pregnancy plasma n-3 and n-6 polyunsaturated fatty acids (PUFAs) and fetal health determined by fetal growth velocity, birth weight and duration of pregnancy.

METHODS

Participants were 6974 pregnant women and their infants from a population-based birth cohort, the Generation R Study. Maternal plasma n-3:n-6 PUFA ratio and n-3 and n-6 PUFA percentage in glycerophospholipids in mid-pregnancy were related to fetal growth velocity calculated from repeatedly measured weight, length and head circumference, birth weight, and duration of pregnancy.

RESULTS

A higher maternal mid-pregnancy n-3:n-6 PUFA ratio was associated with a higher growth velocity of the fetal weight (β = 0.082 SD-score/week, 95% CI 0.055; 0.108, P < 0.001), length (β = 0.085 SD-score/week, 95% CI 0.052; 0.119, P < 0.001); and head (β = 0.055 SD-score/week, 95% CI 0.019; 0.091, P = 0.003). We also observed positive associations between n-3:n-6 PUFA ratio and birth weight (β = 0.76 SD-score, 95% CI 0.22; 1.29, P = 0.006), and duration of pregnancy (β = 1.32 weeks, 95% CI 0.24; 2.40, P = 0.02).

CONCLUSIONS

These results are consistent with the hypothesis that a higher n-3:n-6 PUFA ratio is important for fetal health.

Mode of conception does not appear to affect placental volume in the first trimester

OBJECTIVE

To study whether infertility treatments, including IVF and non-IVF fertility treatments, are associated with diseases of placental insufficiency in early gestation. First trimester placental volumes by ultrasound and chorionic villi weight during sampling (CVS) were performed to detect differences between pregnancies conceived spontaneously versus with fertility treatments.

DESIGN

Retrospective cohort.

SETTING

Academic tertiary center.

PATIENT(S)

Women with singleton pregnancies undergoing CVS and first trimester ultrasound from April 2007 to November 2015.

INTERVENTION(S)

Estimated placental volume (EPV) was calculated from ultrasound images using a validated computation and CVS estimated tissue weight was performed using a validated visual analogue scale.

MAIN OUTCOME MEASURE(S)

Adjusted linear regression was used to compare EPV and CVS weight based on mode of conception.

RESULT(S)

A total of 1,977 spontaneous and 334 conceived with fertility treatments (133 non-IVF and 201 IVF) pregnancies were included. Significant differences in maternal age, gravidity, hypertension, and smoking status were identified. EPV and CVS weight were correlated with maternal age, gestational age, and maternal hypertension. Adjusted linear regression showed no difference in EPV in pregnancies conceived with fertility treatments versus spontaneously. The CVS weight was significantly lower in the IVF conceptions in unadjusted univariate analyses. However, after adjusted regression, this was no longer significant.

CONCLUSION(S)

Mode of conception does not appear to affect first trimester placental size. As differences in maternal age, hypertension, and smoking status differ among the groups and are correlated to placental size, it may be the underlying patient population leading to abnormal placentation and insufficiency, not the fertility treatments used.

Parity Conditions the Risk for Low Birth Weight after Maternal Exposure to Air Pollution

Multiparous mothers have greater umbilical blood flow and thus more efficient transport of pollutants than primiparous mothers. We tested a hypothesis that multiparous mothers are more prone to have an infant with low birth weight (LBW) after prenatal exposure to air pollution. A study was conducted on a representative group of more than 74,000 singleton, live, full-term infants. Birth data were obtained from the birth registry, while pollution data were from an environmental monitoring system (Poland). Multiple comparisons were controlled by the false discovery rate procedure (FDR). After standardization, the harmful effect of carbon monoxide (CO) on the odds ratio (OR) for LBW was seen among the multiparous mothers (OR = 1.28; 95% CI 1.06-1.54), while in primiparous mothers it was nonsignificant. The effect of CO on the OR for LBW differed according to parity, which was confirmed by the test for interaction (FDR-adjusted p = 0.03). The interaction between parity and sulfur dioxide (SO₂) was statistically nonsignificant (FDR-adjusted p = 0.08). Multiparous mothers may be more vulnerable to CO than primiparous mothers. Parity may be the modifier of the association between pollutants and the risk of LBW.

Reliability of First-Trimester Ultrasonic Biopsy for the Evaluation of Placental and Myometrial Blood Perfusion and the Prediction of Preeclampsia

OBJECTIVE

Low placental vascularization measured by three-dimensional (3-D) ultrasound with power Doppler can predict preeclampsia. We evaluated the reliability and reproducibility of the ultrasonic sphere biopsy (USSB) technique to evaluate placental and subplacental myometrium vascularization in the first trimester.

METHODS

We performed a secondary analysis of a case-control study nested in a prospective cohort of women with a singleton pregnancy undergoing ultrasound at 11 to 14 weeks' gestation. Women who developed preeclampsia (n = 20) and randomly selected controls (n = 60) were compared. Other controls (n = 60) were also randomly selected to evaluate intra- and inter-observer reproducibility. Using 3-D power Doppler, the vascularization index (VI), flow index (FI), and vascularization flow index (VFI) were measured from the volume of the whole placenta and the subplacental myometrium and from their respective USSB. Pearson's correlation coefficients (cc) with their P-values were calculated.

RESULTS

We observed that USSB is reliable in estimating the vascularization of the whole placenta in the first trimester (cc of VI 0.83; of FI 0.62; and of VFI 0.78; P < 0.001 for all) but was not as reliable for estimating subplacental myometrium vascularization (cc of VI 0.71; of FI 0.35; and of VFI 0.73). Measurement of placental vascularization using USSB showed good to excellent intra- and inter-observer reproducibility (cc of VI 0.86 and 0.85, respectively; of FI 0.75 and 0.75, respectively; and of VFI 0.83 and 0.83, respectively; P < 0.001 for all). Finally, we observed that women who subsequently developed preeclampsia had lower placental USSB VI (2.1 vs 4.8, P = 0.02), FI (32.4 vs. 42.5, P = 0.002), and VFI (0.8 vs. 2.1, P = 0.01) than controls.

CONCLUSION

First-trimester USSB of the placenta using 3-D power Doppler is a reliable and reproducible procedure for estimating placental vascularization and could be used to predict preeclampsia.

Reduced placental volume and flow in severe growth restricted fetuses

OBJECTIVES

To evaluate placental volume and vascular indices in pregnancies with severe fetal growth restriction and determine their correlations to normal reference ranges and Doppler velocimetry results of uterine and umbilical arteries.

METHODS

Twenty-seven fetuses with estimated weights below the 3rd percentile for gestational age were evaluated. Placental volume and vascular indices, including vascularization, flow, and vascularization flow indices, were measured by three-dimensional ultrasound using a rotational technique and compared to a previously described nomogram. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight were calculated. Placental parameters correlated with the Doppler velocimetry results of uterine and umbilical arteries.

RESULTS

The mean uterine artery pulsatility index was negatively correlated with the observed-to-expected placental volume ratio for gestational age, vascularization index and vascularization flow index. The observed-to-expected placental volume ratio for gestational age and observed-to-expected placental volume ratio for fetal weight and vascularization index were significantly lower in the group with a bilateral protodiastolic notch. No placental parameter correlated with the umbilical artery pulsatility index.

CONCLUSIONS

Pregnancies complicated by severe fetal growth restriction are associated with reduced placental volume and vascularization. These findings are related to changes in uterine artery Doppler velocimetry. Future studies on managing severe fetal growth restriction should focus on combined results of placental three-dimensional ultrasound and Doppler studies of uterine arteries.

Utero-placental vascularisation in normal and preeclamptic and intra-uterine growth restriction pregnancies: third trimester quantification using 3D power Doppler with comparison to placental vascular morphology (EVUPA): a prospective controlled study

INTRODUCTION

Preeclampsia (PE) and intra-uterine growth restriction (IUGR) are two major pregnancy complications related to chronic utero-placental hypoperfusion. Three-dimensional power Doppler (3DPD) angiography has been used for the evaluation of utero-placental vascularisation and three vascular indices have been calculated: the vascularisation index (VI), flow index (FI) and vascularisation-FI (VFI). However, several technical endpoints hinder the clinical use of 3DPD as physical characteristics and machine settings may affect 3DPD indices, and so its clinical significance is not yet clear.

OBJECTIVES

The primary objective is to better understand the clinical significance of 3DPD indices by evaluating the relationship between these indices and placental morphometry. Secondary objectives are (i) to determine the impact of machine settings and physical characteristics on 3DPD indices, and (ii) to evaluate physio-pathological placental vascularisation patterns.

METHODS AND ANALYSIS

This is a prospective controlled study. We expect to include 112 women: 84 with normal pregnancies and 28 with PE and/or IUGR (based on our former cohort study on 3DPD indices for PE and/or IUGR prediction (unpublished data)). Within 72 h before planned or semi-urgent caesarean section, utero-placental 3DPD images with five different machine settings will be acquired. Placentas will be collected and examined after surgery and stereological indices (volume density, surface density, length density) calculated. The 3DPD indices (VI, FI and VFI) of the placenta and adjacent myometrium will be calculated. Correlation between Doppler and morphological indices will be evaluated by Pearson or Spearman tests. Agreement between 3DPD indices and morphological indices will be assessed by Bland and Altman plots. The impact of Doppler settings and maternal characteristics on 3DPD indices will be evaluated with a multivariate linear regression model.

ETHICS

The study and related consent forms have been approved by the French Ethics Committee (CPP, Comité de Protection des Personnes) Est III on 4 March 2014.

Discriminative imaging of maternal and fetal blood flow within the placenta using ultrafast ultrasound

Being able to map accurately placental blood flow in clinics could have major implications in the diagnosis and follow-up of pregnancy complications such as intrauterine growth restriction (IUGR). Moreover, the impact of such an imaging modality for a better diagnosis of placental dysfunction would require to solve the unsolved problem of discriminating the strongly intricated maternal and fetal vascular networks. However, no current imaging modality allows both to achieve sufficient sensitivity and selectivity to tell these entangled flows apart. Although ultrasound imaging would be the clinical modality of choice for such a problem, conventional Doppler echography both lacks of sensibility to detect and map the placenta microvascularization and a concept to discriminate both entangled flows. In this work, we propose to use an ultrafast Doppler imaging approach both to map with an enhanced sensitivity the small vessels of the placenta (~100 μm) and to assess the variation of the Doppler frequency simultaneously in all pixels of the image within a cardiac cycle. This approach is evaluated in vivo in the placenta of pregnant rabbits: By studying the local flow pulsatility pixel per pixel, it becomes possible to separate maternal and fetal blood in 2D from their pulsatile behavior. Significance Statement: The in vivo ability to image and discriminate maternal and fetal blood flow within the placenta is an unsolved problem which could improve the diagnosis of pregnancy complications such as intrauterine growth restriction or preeclampsia. To date, no imaging modality has both sufficient sensitivity and selectivity to discriminate these intimately entangled flows. We demonstrate that Ultrafast Doppler ultrasound method with a frame rate 100x faster than conventional imaging solves this issue. It permits the mapping of small vessels of the placenta (~100 μm) in 2D with an enhanced sensitivity. By assessing pixel-per-pixel pulsatility within single cardiac cycles, it achieves maternal and fetal blood flow discrimination.

Predictive accuracy of the first trimester Doppler scan: a meta-study

AIM

To determine sensitivity and cut-off indices of the uterine artery Doppler (UAD) in prediction of preeclampsia and fetal growth restriction (FGR).

METHODS

Seventy-six studies published in 1995-2014, present 298,329 prenatal Doppler screenings performed in nullipara in the first and early second trimesters of singleton pregnancies. The sample is stratified into four groups based on the Doppler sensitivity and specificity indices pertaining to the major clinical endpoints of the cohort.

RESULTS

The FGR diagnostic specificity (r = 0.728) and bilateral notching index (r = 0.803) correlations indicate that the UAD accuracy depends on the placental bed and the screening mode.

CONCLUSIONS

Predictive sensitivity of the UAD increases after 16 weeks + 3 days (115 days) of gestation. The best predictive parameter of preeclampsia and FGR is the placental side uterine artery resistance index which confers to the highest means when the placenta is on the midline (OR 0.9).

First-trimester 3-dimensional power Doppler placental vascularization indices from the whole placenta versus the placental bed to predict preeclampsia: does pregnancy-associated plasma protein a or uterine artery Doppler sonography help?

OBJECTIVES

The purpose of this study was to compare the use of vascular indices derived from the whole placenta to those from the placental bed only for predicting preeclampsia and to determine whether the addition of pregnancy-associated plasma protein A (PAPP-A) and mean uterine artery Doppler values improves prediction.

METHODS

We conducted a secondary analysis of a prospective cohort of women with singletons between 11 and 14 weeks' gestation undergoing sonography for aneuploidy screening. Placental vascularization indices from the whole placenta versus the placental bed were combined with first-trimester maternal serum PAPP-A levels, mean uterine artery Doppler values, or the combination of both to predict the development of preeclampsia or early preeclampsia (delivery <34 weeks). The predictive ability of each vascular index was calculated by using areas under receiver operating characteristic curves. The sensitivity of the model for predicting preeclampsia and early preeclampsia at fixed false-positive rates of 10% and 20% was calculated.

RESULTS

Of 570 women, 48 (8.4%) had preeclampsia, and 10 (1.7%) had early preeclampsia. The area under the curve and sensitivity values for the prediction of preeclampsia or early preeclampsia were not different when evaluating the whole placenta versus the placental bed. Additionally, there was no significant improvement when adding PAPP-A, uterine artery Doppler values, or both. The variables in the model were more sensitive for the prediction of early preeclampsia than preeclampsia.

CONCLUSIONS

Although placental bed vascular indices are modestly predictive of preeclampsia, the addition of PAPP-A and uterine artery Doppler values to vascularization indices in the whole placenta or the placental bed did not significantly improve their predictive ability.

First-trimester 3D power Doppler of the uteroplacental circulation space and fetal growth restriction

OBJECTIVE

The objective of the study was to compare the 3-dimensional power Doppler (3DPD) of the uteroplacental circulation space in the first trimester between women who subsequently deliver growth-restricted vs normally grown neonates.

STUDY DESIGN

This was a prospective observational study of singleton pregnancies at 11-14 weeks' gestation. The 3DPD indices, vascularization index, flow index, and vascularization flow index were determined on a uteroplacental circulation space sphere biopsy with the virtual organ computer-aided analysis program. Growth restriction was defined as a birthweight less than the 10th percentile for gestational age and was evaluated using both population-based and customized birth curves.

RESULTS

Five hundred seventy-seven women were enrolled. Five hundred twenty-six were eligible for analysis using population centiles, and 497 were available for evaluation using customized centiles. There was no difference in the first-trimester 3DPD indices between patients with growth-restricted and normally grown neonates using either curve.

CONCLUSION

Three-dimensional power Doppler indices of the uteroplacental circulation space in the first trimester are similar between neonates who develop growth restriction and those who will grow normally.

[Placental 3D Doppler angiography: current and upcoming applications]

The placental dysfunction, which seems to be caused by a defect of trophoblastic invasion and impaired uterine vascular remodeling since the first trimester, is responsible in a non-exclusive way for the chronic placental hypoxia, resulting secondarily in the intra-uterine growth restriction (IUGR) and/or pre-eclampsia (PE). The quality of utero-placental vasculature is essential for a proper fetal development and a successful progress of pregnancy. However, the in vivo assessment of placental vascularization with non-invasive methods is complicated by the small size of placental terminal vessel and its complex architecture. Moreover, imaging with contrast agent is not recommended to pregnant women. Until recently, the fetal and maternal vascularization could only be evaluated through pulse Doppler of uterine arteries during pregnancy, which has little clinical value for utero-placental vascularization defects assessment. Recently, a non-invasive study, without use of contrast agent for vasculature evaluation of an organ of interest has become possible by the development of 3D Doppler angiography technique. The objective of this review was to make an inventory of its current and future applications for utero-placental vasculature quantification. The main findings of the literature on the assessment of utero-placental vascularization in physiological situation and major placental vascular dysfunction pathologies such as PE and IUGR were widely discussed.

Early pregnancy placental bed and fetal vascular volume measurements using 3-D virtual reality

In this study, a new 3-D Virtual Reality (3D VR) technique for examining placental and uterine vasculature was investigated. The validity of placental bed vascular volume (PBVV) and fetal vascular volume (FVV) measurements was assessed and associations of PBVV and FVV with embryonic volume, crown-rump length, fetal birth weight and maternal parity were investigated. One hundred thirty-two patients were included in this study, and measurements were performed in 100 patients. Using V-Scope software, 100 3-D Power Doppler data sets of 100 pregnancies at 12 wk of gestation were analyzed with 3D VR in the I-Space Virtual Reality system. Volume measurements were performed with semi-automatic, pre-defined parameters. The inter-observer and intra-observer agreement was excellent with all intra-class correlation coefficients >0.93. PBVVs of multiparous women were significantly larger than the PBVVs of primiparous women (p = 0.008). In this study, no other associations were found. In conclusion, V-Scope offers a reproducible method for measuring PBVV and FVV at 12 wk of gestation, although we are unsure whether the volume measured represents the true volume of the vasculature. Maternal parity influences PBVV.

Trophoblast debris extruded from preeclamptic placentae activates endothelial cells: a mechanism by which the placenta communicates with the maternal endothelium

INTRODUCTION

Preeclampsia is characterized by maternal endothelial dysfunction. While the mechanisms leading to preeclampsia are unclear, a factor(s) from the placenta is responsible for triggering the disease. One placental factor implicated in triggering preeclampsia is trophoblast debris which may transmit pathogenic signals from the placenta to endothelial cells. In this study, we investigated whether trophoblast debris from preeclamptic placentae triggered endothelial cell activation.

METHODS

Trophoblast debris from preeclamptic or normotensive placentae, or trophoblast debris from normal placental explants that had been cultured with preeclamptic (n = 14) or normotensive sera (n = 14) was exposed to endothelial cells. Activation of the endothelial cells was quantified by cell surface ICAM-1 and U937 adhesion to endothelial cells. The levels of IL-1β, pro-caspase-1 and active caspase-1 in the trophoblast debris were measured.

RESULTS

Compared to controls, the levels of ICAM-1 and U937 adhesion to endothelial cells were significantly increased following exposure of the endothelial cells to trophoblast debris from preeclamptic placentae or placentae treated with preeclamptic sera. The levels IL-1β, pro-caspase-1 and active caspase-1 were significantly increased in both trophoblast debris from preeclamptic placentae and placentae treated with preeclamptic sera.

DISCUSSION

These results provide the first direct evidence that trophoblast debris produced from preeclamptic placentae or placentae treated with preeclamptic sera can activate the endothelium.

CONCLUSIONS

Trophoblast debris from preeclamptic but not normotensive placentae can induce endothelial cell activation. This may be one mechanism by which the preeclamptic placenta communicates with the maternal endothelium to induce activation of the endothelium.

First trimester screening can predict adverse pregnancy outcomes

There has been an increasing drive over the last two decades to push the detection of women at risk of adverse pregnancy outcomes into the first trimester. This has led to a plethora of techniques, risk assessments and biomarkers, both fascinating and bewildering in its breadth. Despite the vast amount of knowledge available, it is often difficult to determine what is practicable and valuable for clinical practice. This is especially true as earlier diagnosis does not necessarily equate to improved outcomes for mother and child. We suggest that, at least for preeclampsia, fetal growth restriction, spontaneous preterm birth and gestational diabetes, there are effective first trimester tests available to identify the women at risk of subsequently developing complications. Unfortunately, there are no currently reliable first trimester tests available for identifying women at risk of stillbirth. It is likely that this field will continue to develop over time, and we hope that new and better strategies will continue to emerge to target these clinically important pathologies.

First trimester pregnancy volumes and subsequent small for gestational age fetuses

OBJECTIVE

To examine whether in the first trimester, placental, gestational sac and fetal volumes are different in pregnancies that result in small for gestational age (SGA) compared to average for gestational age (AGA) neonates.

METHODS

Case-control study comparing first trimester 3D volumes of the placenta, the fetus and the gestational sac between SGA and AGA pregnancies. 3D volumes were acquired for quality assurance and documentation. Pregnancy volumes were calculated by the virtual organ computer-aided analysis technique. Linear regression analysis was used to compute a normal range for the placental, gestational sac and fetal volume based on the crown rump length (CRL) in AGA pregnancies. Multiple regression analysis was used to examine significant influencing covariates. A Student's t test was used to compare the difference between the SGA and AGA group.

RESULTS

The study population consisted of 19 first trimester pregnancies with subsequent SGA neonates and 105 control pregnancies. In the AGA group, all pregnancy volumes were significantly dependent on the CRL. After controlling the CRL effect, the placental, gestational sac and fetal volumes were not significantly different between the SGA and AGA group.

CONCLUSION

First trimester 3D pregnancy volume measurements are not different in SGA or AGA pregnancies.