First trimester placental volume and vascular indices in pregnancies complicated by preeclampsia

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.

First-trimester 3D power Doppler imaging markers of utero-placental vascular development are associated with placental weight and diameter at birth: The Rotterdam Periconception Cohort

INTRODUCTION

Early utero-placental vascular development impacts placental development and function throughout pregnancy. We investigated whether impaired first-trimester utero-placental vascular development is associated with pathologic features of the postpartum placenta.

METHODS

In this prospective observational study of 65 ongoing pregnancies, we obtained three-dimensional power Doppler ultrasounds of the placenta at 7, 9 and 11 weeks of gestation. We applied VOCAL software to measure placental volume (PV), virtual reality based segmentation to measure utero-placental vascular volume (uPVV) and applied a skeletonization algorithm to generate the utero-placental vascular skeleton (uPVS). Vascular morphology was quantified by assigning a morphologic characteristic to each voxel in the uPVS (i.e. end-, bifurcation-, crossing- or vessel point). Following delivery, placentas were measured and histologically examined according to the Amsterdam criteria to assess maternal vascular malperfusion (MVM). We used linear mixed models to estimate trajectories of PV, uPVV and uPVS development. Multivariable linear regression analysis with adjustments for confounders was used to evaluate associations between PV, uPVV and uPVS development and features of the postpartum placenta.

RESULTS

We observed no associations between first-trimester PV development and measurements of the postpartum placenta. Increased first-trimester utero-placental vascular development, reflected by uPVV (β = 0.25 [0.01; 0.48]), uPVS end points (β = 0.25 [0.01; 0.48]), bifurcation points (β = 0.22 [0.05; 0.37]), crossing points (β = 0.29 [0.07; 0.52]) and vessel points (β = 0.09 [0.02; 0.17]) was positively associated with the postpartum placental diameter. uPVV was positively associated with postpartum placental weight. No associations were found with MVM.

DISCUSSION

Development of the first-trimester utero-placental vasculature is associated with postpartum placental size, whereas placental tissue development contributes to a lesser extent.

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.

A mathematical model of vascular and hemodynamics changes in early and late forms of preeclampsia

Preeclampsia-eclampsia syndrome is a leading cause of maternal mortality. The precise etiology of preeclampsia is still not well-defined and different forms exist, including early and late forms or preeclampsia, which may arise via distinctly different mechanisms. Low-dose aspirin administered at the end of the first trimester in women identified as high risk has been shown to reduce the incidence of early, but not late, preeclampsia; however, current risk factors show only fair predictive capability. There is a pressing need to develop accurate descriptions for the different forms of preeclampsia. This paper presents 1D fluid, solid, growth, and remodeling models for pregnancies complicated with early and late forms of preeclampsia. Simulations affirm a broad set of literature results that early forms of preeclampsia are characterized by elevated uterine artery pulsatility index (UA-PI) and total peripheral resistance (TPR) and lower cardiac output (CO), with modestly increased mean arterial blood pressure (MAP) in the first half of pregnancy, with elevation of TPR and MAP beginning at 20 weeks. Conversely, late forms of preeclampsia are characterized by only slightly elevated UA-PI and normal pre-term TPR, and slightly elevated MAP and CO throughout pregnancy, with increased TPR and MAP beginning after 34 weeks. Results suggest that preexisting arterial stiffness may be elevated in women that develop both early forms and late forms of preeclampsia; however, data that verify these results are lacking in the literature. Pulse wave velocity increases in early- and late-preeclampsia, coincident with increases in blood pressure; however, these increases are mainly due to the strain-stiffening response of larger arteries, rather than arterial remodeling-derived changes in material properties. These simulations affirm that early forms of preeclampsia may be associated with abnormal placentation, whereas late forms may be more closely associated with preexisting maternal cardiovascular factors; simulations also highlight several critical gaps in available data.

A mathematical model of maternal vascular growth and remodeling and changes in maternal hemodynamics in uncomplicated pregnancy

The maternal vasculature undergoes tremendous growth and remodeling (G&R) that enables a > 15-fold increase in blood flow through the uterine vasculature from conception to term. Hemodynamic metrics (e.g., uterine artery pulsatility index, UA-PI) are useful for the prognosis of pregnancy complications; however, improved characterization of the maternal hemodynamics is necessary to improve prognosis. The goal of this paper is to develop a mathematical framework to characterize maternal vascular G&R and hemodynamics in uncomplicated human pregnancies. A validated 1D model of the human vascular tree from the literature was adapted and inlet blood flow waveforms at the ascending aorta at 4 week increments from 0 to 40 weeks of gestation were prescribed. Peripheral resistances of each terminal vessel were adjusted to achieve target flow rates and mean arterial pressure at each gestational age. Vessel growth was governed by wall shear stress (and axial lengthening in uterine vessels), and changes in vessel distensibility were related to vessel growth. Uterine artery velocity waveforms generated from this model closely resembled ultrasound results from the literature. The literature UA-PI values changed significantly across gestation, increasing in the first month of gestation, then dramatically decreasing from 4 to 20 weeks. Our results captured well the time-course of vessel geometry, material properties, and UA-PI. This 1D fluid-G&R model captured the salient hemodynamic features across a broad range of clinical reports and across gestation for uncomplicated human pregnancy. While results capture available data well, this study highlights significant gaps in available data required to better understand vascular remodeling in pregnancy.

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.

The influence of frozen-thawed and fresh embryo transfer on utero-placental (vascular) development: the Rotterdam Periconception cohort

STUDY QUESTION

Does frozen-thawed or fresh embryo transfer (ET) influence utero-placental (vascular) development, when studied using three-dimensional (3D) ultrasound and virtual reality imaging techniques?

SUMMARY ANSWER

In the first trimester, placental developmental parameters, that is, placental volume (PV) and utero-placental vascular volume (uPVV), were comparable between pregnancies resulting from frozen-thawed ET, fresh ET and natural conception; and in the second and the third trimester, uterine artery Doppler indices were lower in pregnancies after frozen-thawed ET compared to pregnancies after fresh ET and natural conception.

WHAT IS KNOWN ALREADY

Pregnancies after frozen-thawed ET are at risk of developing placenta-related pregnancy complications. There is strong evidence that impaired first-trimester spiral artery remodelling is involved in the pathophysiology of these complications. Studies on longitudinal placental development in pregnancies with different modes of conception, that is, after frozen-thawed ET, fresh ET or natural conception, are lacking.

STUDY, DESIGN, SIZE, DURATION

Women with singleton pregnancies were included before 10 weeks of gestation, between January 2017 and July 2018, as a subcohort of the ongoing Rotterdam Periconception cohort. Results were partially validated in 722 women from the total cohort, which was conducted from November 2010 onwards.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 214 women, of whom 32 conceived after frozen-thawed ET, 56 conceived after fresh ET and 126 conceived naturally, were selected. PV and uPVV measurements were obtained at 7, 9 and 11 weeks of gestation by transvaginal 3D (power Doppler) ultrasound. The uterine artery pulsatility index (UtA-PI) and resistance index (UtA-RI) were measured transvaginally at 7, 9, 11 and 13 weeks and abdominally at 22 and 32 weeks of gestation by pulsed wave Doppler ultrasound. In the validation cohort, the PV was measured in 722 women. Associations between mode of conception and placental development were studied using linear mixed models.

MAIN RESULTS AND THE ROLE OF CHANCE

First-trimester parameters of placental development, that is, PV, uPVV, UtA-PI and UtA-RI, were comparable between pregnancies after frozen-thawed and fresh ET and naturally conceived pregnancies. In our validation cohort, comparable results were found for PV. However, the second- and third-trimester UtA-PI and UtA-RI in pregnancies after frozen-thawed ET were significantly lower than in pregnancies after fresh ET (β_UtA-PI −0.158 (95% CI: −0.268, −0.048), P = 0.005; β_UtA-RI −0.052 (95% CI: −0.089, −0.015), P = 0.006). The second- and third-trimester uterine artery indices in pregnancies after fresh ET were comparable to those in pregnancies after natural conception.

LIMITATIONS, REASONS FOR CAUTION

The main limitation of this study is the lack of power to optimally detect differences in placental development and placenta-related pregnancy outcomes between pregnancies after different modes of conception. Moreover, our population was selected from a tertiary hospital and included a relatively limited number of pregnancies. Therefore, external validity of the results should be confirmed in a larger sample size.

WIDER IMPLICATIONS OF THE FINDINGS

These findings indicate no significant impact of conception mode on early placental development and a beneficial impact for frozen-thawed ET on the second- and third-trimester Doppler indices. This suggests that frozen-thawed ET may not be as detrimental for placental perfusion as previous research has demonstrated. As the number of clinics applying the ‘freeze-all strategy’ increases, future research should focus on establishing the optimal uterine environment, with regards to hormonal preparation, prior to ET to reduce placental-related pregnancy complications after frozen-thawed ET.

STUDY FUNDING/COMPETING INTEREST(S)

This research was funded by the Erasmus MC Medical Research Advisor Committee’s ‘Health Care Efficiency Research’ program and the department of Obstetrics and Gynaecology of the Erasmus MC, University Medical Center, Rotterdam, The Netherlands. JSEL reports grants and personal fees from Ferring, personal fees from Titus Healthcare, grants and personal fees from Ansh Labs, grants from NIH, grants from Dutch Heart Association and grants from ZonMW outside the submitted work. None of the other authors have a conflict of interest.

TRIAL REGISTRATION NUMBER

Registered at the Dutch Trial Register (NTR6684).

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 placental vascular indices and volume by three-dimensional ultrasound in pre-gravid overweight women

OBJECTIVES

To investigate changes of placental vascular indices and volume in pre-gravid overweight Chinese women during the first trimester using three-dimensional power Doppler ultrasound.

METHODS

This was a prospective observational study of the morphology of placentas in pre-gravid overweight (body mass index (BMI) ≥ 24 kg/m²) and non-overweight (BMI < 24 kg/m²) Chinese women during the first trimester of pregnancy. Data on placental vascular indices (vascularization index, flow index, and vascularization flow index (VFI)), placental volume, uterine artery pulsatility index (PI), and neonatal outcomes were obtained during the first trimester and analyzed. Linear regression analysis was used to evaluate confounding factors between BMI and ultrasound indices.

RESULTS

Of the 429 pregnant women enrolled, 68 (15.9%) were pre-gravid overweight. Placental VFI was significantly lower in the overweight group (p = 0.037). Conversely, placental volume was significantly larger in the overweight group (p = 0.044), and uterine artery PI was significantly higher in the overweight group (p = 0.021). After adjustments for confounding factors, there were still significant differences in placental VFI (unstandardized coefficient (B) -0.666, 95% confidence interval (CI) -1.306 - (-0.025)), placental volume (B 2.458, 95% CI 0.071-4.844), and uterine artery PI (B 0.152, 95% CI 0.030-0.274) between the two groups.

CONCLUSIONS

Placental vascular indices using three-dimensional power Doppler ultrasound can provide an insight into placental vascularization in pre-gravid overweight women in early pregnancy. Alterations in placental VFI, placental volume, and uterine artery PI occur during the first trimester in pre-gravid overweight women.

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.

Placental volume at 11 to 14 gestational weeks in pregnancies complicated with fetal growth restriction and preeclampsia

OBJECTIVE

The study aims to evaluate the predictive value of first trimester placental volume in pregnancies destined to develop fetal growth restriction (FGR) and preeclampsia (PE).

METHODS

Prospective observational study including placentas from 34 FGR, 12 PE, 15 GH (gestational hypertension) pregnancies, and 265 controls. Placental volume (PV) was obtained using VOCAL technique, and a z score was calculated (z-PV). The association of PV with other first trimester variables and maternal characteristics was assessed with Spearman's correlation.

RESULTS

PV increased exponentially with crown-rump length (CRL) and was unrelated to maternal factors (weight, age, parity, and smoking status) as well as first trimester uterine artery Doppler, free β-hCG, nuchal translucency, or fetal heart rate. However, PV was positively associated with maternal height, CRL, PAPP-A, and birth weight. z-PV was a strong predictor for FGR with abnormal fetal Dopplers (AUC = 0.9472, P < 0.001). z-PV provided moderate prediction of FGR with normal fetal Dopplers (AUC = 0.8396, P < 0.001), PE (AUC = 0.8312, P < 0.001), and GH (AUC = 0.7640, P < 0.001). The addition of maternal weight, PAPP-A, β-hCG, and uterine artery Doppler improved our models.

CONCLUSION

At 11 to 14 weeks, PV is an independent predictor of pregnancy complications related to placental insufficiency, and the predictive ability is greater for FGR pregnancies with abnormal fetal Dopplers.

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.

Preeclampsia and the challenge of early prediction: reality or utopia? State of art and critical review of literature

Purpose: The challenge to obtain improved predictive tools, able to identify women destined to develop preeclampsia (PE), is raising the interest of researchers for the attractive chance to allow for timely initiation of prophylactic therapy, appropriate antenatal surveillance, and better-targeted research into preventive interventions. We aimed to gather all the evidence reported up to now in scientific literature relating to all prediction tests for PE.Materials and methods: We searched articles on conventional literature platforms from January 1952 to August 2016, using the terms "preeclampsia," "gestational preeclampsia," and "gestational hypertensive disorders" combined with "predictive test" and "risk assessment." Abstracts/titles identified by the search were screened by three investigators.Results: The search identified 203 citations, of which 154 potentially relevant after the initial evaluation. Among these studies, 20 full articles were excluded, therefore, 134 primary studies met the criteria for inclusion and were analyzed.Conclusions: Current evidence suggests that a combination of several features may provide the best predictive accuracy for the identification of PE. Large-scale, multicenter, multiethnic, prospective trials are required to propose an ideal combination of markers for routine screening.

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

INTRODUCTION

We evaluated the utility of placental volume and three-dimensional (3D) vascular flow indices to predict early and late preeclampsia.

MATERIAL AND METHODS

In 1,004 pregnancies attending routine care, we recorded first-trimester screening program for aneuploidy (FTSA) parameter and measured uterine artery pulsatility index (uterine-a PI). Placental volume and vascular flow indices were obtained using 3D power Doppler and VOCAL techniques.

RESULTS

Placental volume was lower and uterine-a PI was higher in both early and late preeclampsia groups versus nonaffected pregnancies. The prediction rate of placental volume in late preeclampsia was higher than that of uterine-a PI (AUROC 0.707 vs. 0.581, p < 0.011). The inclusion of placental volume improved significantly the prediction rate of total and late preeclampsia in the models constructed with maternal characteristics, FTSA, and uterine-a PI (AUROC 0.745 vs. 0.818, p < 0.004, and 0.740 vs. 0.812, p < 0.012, respectively). The inclusion of vascular indices did not improve the predictive value of these models.

DISCUSSION

Placental volume was an independent predictor of total, early, and late preeclampsia and its inclusion in combined predictive models significantly improved prediction rates. Reduced placental volume observed at first trimester in women with early and late preeclampsia suggests that these entities are the clinical expression of a similar pathophysiological process.

Using critical flicker frequency in the evaluation of visual impairment in preeclamptic women

OBJECTIVE

To assess critical flicker frequency (CFF) in normal uneventful pregnancy and preeclampsia.

STUDY-DESIGN

Case-control observational study at the University Hospital Jena and Outpatient Institute for Prenatal Diagnosis and Preventive Medicine. 25 non-pregnant women, 75 uncomplicated pregnant women in first, second and third trimester, and 15 women with overt preeclampsia. For comparison with preeclamptic patients we matched 15 normal pregnant women (mNP) for age, parity, body mass index, current smoking and family history of cardiovascular disease (CVD). We measured CFF using the portable HEPAtonorm Analyzer (nevoLAB GmbH, Germany). This device generates a flickering red light, starting with a frequency of 60Hz, giving the subjective an impression of a steady light. The participant signifies once the impression of a flickering light is recognized, and this CFF is recorded. Mean CFF and standard deviation is automatically calculated. Statistical analysis was performed using SPSS Version 22 for Windows. Following assessment of normal distribution with Kolmogorov-Smirnow test, comparisons were made with univariate and multivariate ANOVA and with unpaired and paired t test for continuous data and with χ² test for categorical data.

RESULTS

Critical flicker frequency in healthy pregnant women does not differ from nonpregnant women. No significant differences in CFF measurements exist in first, second, and third trimester. In preeclampsia, CFF is significantly decreased compared to normal pregnant women (PE 38.80±2.16 vs. mNP 46.23±3.37; p=0.000). This alteration persists even some weeks postpartum (PE 41.17±1.13 vs. mNP 46.45±3.44; p=0.003).

CONCLUSION

In preeclamptic women, CFF is decreased indicating an altered endothelial situation. The finding that CFF remains reduced postpartum may be explained by either the effect of preeclampsia on maternal endothelium causing longer lasting damage or indicate a preexisting endothelial disorder. Up to this point, precise responsible mechanisms for altered CFF in preeclampsia are currently unclear and further studies are needed.