Value of Placental Volume and Vascular Flow Indices as Predictors of Early and Late Preeclampsia at First Trimester

Spiral, uterine artery doppler and placental ultrasound in relation to preeclampsia

Preeclampsia (PE) is a multiorgan disorder that complicates around 2-8% of pregnancies and is a major cause of perinatal and maternal morbidity and mortality. PE is a clinical syndrome characterized by hypertension secondary to systemic inflammation, endothelial dysfunction, and syncytiotrophoblast stress leading to hypertension and multiorgan dysfunction. The uterine arteries are the main blood vessels that supply blood to the uterus. They give off branches and plays an important role in maintaining blood supply during pregnancy. The arcuate artery originates from the uterine artery and runs medially through the myometrium. The arcuate arteries divide almost directly into anterior and posterior branches, from which the radial artery leads directly to the uterine cavity during their course. Near the endometrium-myometrium junction, the radial artery generates spiral arteries within the basal layer and functional endometrium. The walls of radial and spiral arteries are rich in smooth muscle, which is lost when trophoblast cells invade and become large-caliber vessels. This physiological transformation of uteroplacental spiral arteries is critical for successful placental implantation and normal placental function. In normal pregnancy, the luminal diameter of the spiral arteries is greatly increased, and the vascular smooth muscle is replaced by trophoblast cells. This process and changes in the spiral arteries are called spiral artery remodeling. In PE, this genetically and immunologically governed process is deficient and therefore there is decreased vascular capacitance and increased resistance in the uteroplacental circulation. Furthermore, this defect in uteroplacental spiral artery remodeling is not only associated with early onset PE, but also with fetal growth restriction, placental abruption, and spontaneous premature rupture of membranes. Doppler ultrasound allows non-invasive assessment of placentation, while the flow impedance decreases as the pregnancy progresses in normal pregnancies, in those destined to develop preeclampsia the impedance is increased.

The clinical value of combining shear wave elastography, VOCAL technique, and T2* MRI of early gestation placenta to predict pre-eclampsia

OBJECTIVE

To investigate the clinical value of combining shear wave elastography (SWE) with the Volumetric Organ Computer-Aided AnaLysis (VOCAL) technique and T2* magnetic resonance imaging (MRI) to predict pre-eclampsia (PE).

METHODS

From December 2022 to March 2023, we recruited 31 pregnant women diagnosed with PE at our hospital as the observation group and 85 normal pregnant women as the control group. Differences in placental elasticity, vascularization index (VI), flow index (FI), vascularization flow index (VFI), and T2* MRI perfusion fraction (f) were compared between the two groups. Received operating characteristic (ROC) curve analysis was performed to evaluate the diagnostic value of placental elasticity, VI, FI, VFI, f, and their combination for predicting PE.

RESULTS

Placental elasticity was higher in the observation group than in the control group, while VI, FI, VFI, and f were lower in the observation group (all p < 0.05). The area under the curve (AUC) for placental elasticity, VI, FI, VFI, f, and their combination for predicting PE were 0.85, 0.77, 0.78, 0.84, 0.65, and 0.94, respectively. The sensitivity was 71%, 55%, 94%, 65%, 55%, and 81%. The specificity was 92%, 91%, 60%, 92%, 79%, and 98%. The combined prediction model had a higher AUC than the individual predictors (p < 0.05).

CONCLUSION

SWE combined with VOCAL technique and T2* MRI has high value for predicting PE and can provide reference information for clinical diagnosis.

Does a Caesarean Section Scar Affect Placental Volume, Vascularity and Localization?

Caesarean section is associated with an increased risk of abnormal placental implantation and adverse pregnancy outcomes in subsequent pregnancies. Besides the placenta accrete spectrum, only a few of the previous studies focused on other placental development alterations in the scarred uterus. We assessed placental development deviations in the uterus with a Caesarean section scar by evaluating placental volume (PV) and vascular flow indexes. From 1 January 2021 until 31 March 2022, placental volumes and vascularization indexes (VI, FI, VFI) were prospectively measured by 3D power Doppler and VOCAL techniques in 221 patients attending the first trimester screening program. We also calculated the placental quotient to standardize PV to the gestational age. No statistically significant differences in the values of placental volume, placental quotient and placental vascularization indexes were detected between women with previous Caesarean section delivery or women with vaginal delivery. FI was significantly lower in nulliparous in the first trimester. The results of our study suggest that 3D placental evaluation was not able to detect placental development alteration in the uterus with a Caesarean section scar. Future research needs to verify whether 3D power Doppler and Vocal techniques can provide more information if used in an earlier gestational age.

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.

Periconceptional maternal and paternal homocysteine levels and early utero-placental (vascular) growth trajectories: The Rotterdam periconception cohort

INTRODUCTION

Maternal elevated plasma total homocysteine (tHcy) is involved in the origin of several placenta-related pregnancy complications. The first trimester is the most sensitive period for placentation influenced by maternal and paternal health. The aim is to study associations between periconceptional parental tHcy levels and utero-placental growth trajectories in the first trimester of pregnancy.

METHODS

Pregnant women and their partners were enrolled before 10 weeks of gestation in the Virtual Placenta study as subcohort of the Rotterdam periconception cohort (Predict study). A total of 190 women with a singleton pregnancy, of which 109 conceived naturally and 81 after IVF/ICSI treatment, were included. We measured serial utero-placental vascular volumes (uPVV) and placental volumes (PV) at 7, 9 and 11 weeks of gestation. First-trimester trajectories of PV were also measured in 662 pregnancies from the total Predict study.

RESULTS

Comparing all participants of the virtual placenta study, no association between maternal tHcy and uPVV was observed. However, in IVF/ICSI pregnancies sub-analyses showed significantly negative associations between maternal tHcy in the 3rd and 4th quartile and uPVV trajectories (beta: -0.38 (95%CI -0.74 to -0.02) and beta: -0.42 (95% CI -0.78 to -0.05), respectively) with the 1st quartile as reference. Analysis in the total Predict cohort showed similar negative associations for the total study population.

DISCUSSION

Periconceptional high maternal tHcy levels are associated with smaller placental growth trajectories depicted as PV and uPVV in the first trimester of pregnancy. The stronger negative associations with uPVV in IVF/ICSI pregnancies underline the need for further investigation.

A 10-Year Retrospective Review of Prenatal Applications, Current Challenges and Future Prospects of Three-Dimensional Sonoangiography

Realistic reconstruction of angioarchitecture within the morphological landmark with three-dimensional sonoangiography (three-dimensional power Doppler; 3D PD) may augment standard prenatal ultrasound and Doppler assessments. This study aimed to (a) present a technical overview, (b) determine additional advantages, (c) identify current challenges, and (d) predict trajectories of 3D PD for prenatal assessments. PubMed and Scopus databases for the last decade were searched. Although 307 publications addressed our objectives, their heterogeneity was too broad for statistical analyses. Important findings are therefore presented in descriptive format and supplemented with the authors’ 3D PD images. Acquisition, analysis, and display techniques need to be personalized to improve the quality of flow-volume data. While 3D PD indices of the first-trimester placenta may improve the prediction of preeclampsia, research is needed to standardize the measurement protocol. In highly experienced hands, the unique 3D PD findings improve the diagnostic accuracy of placenta accreta spectrum. A lack of quality assurance is the central challenge to incorporating 3D PD in prenatal care. Machine learning may broaden clinical translations of prenatal 3D PD. Due to its operator dependency, 3D PD has low reproducibility. Until standardization and quality assurance protocols are established, its use as a stand-alone clinical or research tool cannot be recommended.

Combination of three-dimensional placental vascular indices and volume and uterine artery pulsatility index at 10-13 weeks of gestation could improve the prediction of adverse pregnancy outcomes

AIM

To evaluate whether three-dimensional (3D) placental vascular indices and volumes during the first trimester of pregnancy can be used as predictors of subsequent adverse outcomes.

METHODS

This was a prospective cohort study including women with singleton pregnancies between 10 and 13 weeks. 3D placental volume and vascular indices and uterine artery pulsatility index (UtA-PI) were measured. Adverse outcomes were defined whether there was any of the following complications: small for gestational age pregnancy, preterm delivery, and preeclampsia. The serum pregnancy-associated plasma protein-A (PAPP-A) and free beta-human chorionic gonadotropin (β-hCG) levels were also compared. We analyzed the screening performances of these parameters for prediction of any of adverse outcomes.

RESULTS

Of 348 women screened, 300 women were completed follow-up. Overall, 57 (19.0%) of 300 women developed any of adverse pregnancy outcomes. Multiple logistic regression analysis demonstrated that gestational age-adjusted z-scores of log₁₀ placental volume (odds ratio [OR], 0.572; 95% confidence interval [CI], 0.416-0.788), log₁₀ placental vascularization flow index (VFI; OR, 0.676; 95% CI, 0.496-0.921), and log₁₀ UtA-PI (OR, 1.910; 95% CI, 1.335-2.731) were significantly associated adverse pregnancy outcomes. The multivariate model combining placental VFI, placental volume, UtA-PI, and underweight or obese body mass index exhibited the highest screening performances (AUC = 0.77) and PAPP-A and β-hCG did not add any significance to multivariate model.

CONCLUSIONS

Placental volume and vascular indices at 10-13 weeks of gestation are significantly associated with adverse pregnancy outcomes. Combination of these placental indices and UtA-PI could improve the screening performance for adverse outcomes.

First trimester placental volume is reduced in hypertensive disorders of pregnancy associated with small for gestational age fetus

INTRODUCTION

Trophoblastic invasion and placental growth are critical for pregnancy outcome. The placental volume can be assessed by 3 D ultrasound using Virtual Organ Computer-aided Analysis (VOCAL). Epidemiological and clinical data suggest that there are two different clinical phenotypes of hypertensive disorders of pregnancy (HDP) that coexist at any gestational age: HDP associated to fetal growth impairment and HDP associated to appropriate for gestational age fetal growth. The aim of this study was to determine whether placental volume in the first trimester of pregnancy differs between women with HDP associated or not to fetal growth impairment and uncomplicated pregnancies.

METHODS

This is a retrospective cross-sectional study of prospectively recruited data in which maternal characteristics, Doppler velocimetry of uterine arteries, and three-dimensional (3 D) volume of the placenta were collected at 11 + 1 - 13 + 6 gestational weeks. The placental quotient (PQ) was calculated as placental volume/crown rump length.

RESULTS

In a 2-year period, we prospectively collected first trimester data of 1322 women. For the purposes of this cross-sectional study, 57 women that delivered a SGA fetus, 34 that developed HDP-AGA, and six that developed HDP-SGA, respectively, were included in the study as cases. The control group was made of 117 uncomplicated pregnancies. The PQ was higher in women with uncomplicated pregnancies (PQ median 16.36 cm³/cm) than in all other study groups (PQ in SGA: 13.02 cm³/cm, p < .001; PQ in HDP-AGA: 12.65 cm³/cm, p = .002; and PQ in women with HDP-SGA: 8.33 cm³/cm [IQR 6.50-10.13], p < .001). The lowest PQ was observed in women with HDP-SGA and was significantly lower than PQ in either women with SGA or those with HDP-AGA (p = .02 and p = .04, respectively). The mean uterine artery pulsatility index was the highest in women with HDP-SGA (median 2.30) compared to all other groups (uncomplicated pregnancies 1.48, p < .0001; women with SGA 1.59, p = .001; and women with HDP-AGA 1.75, p = .009).

DISCUSSION

Our findings suggest that HDP associated with SGA is characterized by impaired placental growth and perfusion as soon as in the first trimester of pregnancy. The role of PQ, isolated or in association with other biophysical parameters, to predict HDP with fetal growth impairment remains to be evaluated.

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.

Preeclampsia – Prediction and Monitoring Factors

Preeclampsia is one of the leading causes of maternal and perinatal morbidity and mortality, usually characterized by hypertension and proteinuria. Despite high incidence of preeclampsia the pathophysiological basis of preeclampsia is still not clear and there are a number of mechanisms and signaling pathways that intertwine. It is very important to develop specific and reliable predictive algorithms in order to enable early initiation of therapy due to facts that incidence of preeclampsia has upward trend and that cause adverse maternal and fetal outcome. Some of the most commonly used methods for prediction of preeclampsia include uterine artery Doppler velocimetry, determination of some microRNA, such as miR-210, and assessment of various pro-angiogenic and anti-angiogenic factors from blood. Angiogenic factors that possibly have most important role in pathogenesis of preeclampsia are vascular endothelial growth factor (VEGF) and placental growth factor (PlGF), which promote angiogenesis, and soluble fms-like tyrosine kinase-1 (sFlt1) and soluble form of endoglin (s-Eng), which exhibit anti-angiogenic properties. Aggravating circumstance is that preeclampsia has heterogeneous origin, and due to this fact, the value of individual markers can vary significantly. There is a constant tendency for creating comprehensive algorithm for prediction of preeclampsia which would be sufficiently specific and sensitive, and in the same time cheap and available. In that sense, new clinical studies are needed to show the most effective combination of parameters in the predeclampsia prediction.

First trimester 3D ultrasound placental volume for predicting preeclampsia and/or intrauterine growth restriction

The objective of the study was to determine the sensitivity of the placental volume for predicting preeclampsia and/or intrauterine growth restriction (IUGR) in the first trimester. A prospective observational study was conducted in pregnant women with a gestational age of 11 to 13⁺⁶ weeks. A 3 D transabdominal placental volume measurement was performed at the time of first-trimester aneuploidy screening. The predictive values of this test were calculated. The data from 360 pregnant women was analysed. Seventeen cases developed preeclampsia and/or IUGR. The 10^th percentile of placental volume was used as the cut-off level. The sensitivity, specificity, positive predictive value and negative predictive value of placental volume less than the 10^th percentile for prediction of preeclampsia and/or IUGR were 23.5%, 90.7%, 11.1% and 96%, respectively. The sensitivity, specificity, positive predictive value and negative predictive value for prediction of early onset preeclampsia were 50%, 90.7%, 3.0% and 99.7%, respectively. This study demonstrated that the placental volume was lower in the cases with preeclampsia and/or IUGR. It was not an effective screening tool for preeclampsia and/or IUGR in the first trimester. IMPACT STATEMENT What is already known on this subject? Placental volume may reflect trophoblast invasion, but much earlier, in the first trimester. The estimation of a smaller early placental volume has been shown to be significantly associated with preeclampsia and IUGR. What do the results of this study add? The placental volume was lower in the cases with preeclampsia and/or IUGR. It was not an effective screening tool for preeclampsia and/or IUGR in the first trimester. But it might be used for predicting early onset preeclampsia. What are the implications of these findings for clinical practice and/or further research? Further research of placental volume in the first trimester for predicting an early onset preeclampsia should be conducted.