Cumulative effect of maternal vascular malperfusion types in the placenta on adverse pregnancy outcomes

Does Amsterdam criteria applied to largely unsubmitted term placentas with favorable fetal outcomes show significant maternal clinicopathologic correlation?

OBJECTIVES

Before the Amsterdam Placental Workshop Group Consensus Statement, standardization in placental pathology assessment did not exist. This study evaluated the Amsterdam criteria's utility in correlating ischemic placental disease (IPD) with placental pathologic lesions in a cohort of largely unsubmitted term placentas with favorable outcomes.

METHODS

In this prospective case-controlled study at a single institution, all placentas were examined using Amsterdam protocols for gross sampling and microscopic review by 2 reviewers who were blinded to clinical history. Pathologic findings including hypoxic and chronic villitis of unknown etiology (VUE) scores were correlated with IPD status and whether the placenta was submitted to pathology using either a χ² test or Fisher exact test, as appropriate.

RESULTS

A total of 172 placentas collected between 2017 and 2020 were included. Approximately 18.6% (n = 32) were in the IPD group, and 81.4% (n = 140) were in the non-IPD group. No statistically significant differences in microscopic findings were seen in ascending infection, maternal vascular malperfusion, fetal vascular malperfusion, or VUE between groups or by submission status. When tabulated as a hypoxic score, placentas from the IPD group were associated with greater hypoxic scores compared to non-IPD placentas (P = .011). A positive association was observed between greater VUE scores and hypoxic scores (P = .007).

CONCLUSIONS

In largely unsubmitted term placentas, the microscopic findings per Amsterdam criteria may be nonspecific. When tabulated as hypoxic or VUE scores, however, some clinicopathologic correlation may be seen in the setting of IPD. Further work is needed to refine the thresholds of meaningful reporting of placental pathology using the Amsterdam criteria.

Difference in adverse neonatal outcomes between preterm singletons and twins possibly explained by placental abnormalities

INTRODUCTION

The purpose of this study was to compare microscopic placental characteristics between preterm twins and singletons, and between preterm monochorionic and dichorionic twins, in order to explore the effect of placental pathology on adverse neonatal outcomes.

METHODS

This study included 566 neonates born ≤32 weeks and/or ≤1500 g, of whom 429 were singletons and 137 were twins (38 monochorionic and 99 dichorionic). Clinical data was retrospectively collected, and placentas were prospectively examined for maternal vascular malperfusion, fetal vascular malperfusion and placental inflammation (acute and chronic).

RESULTS

Singletons had increased rates of maternal vascular malperfusion, fetal hypoxia, funisitis (in umbilical cord and chorial plate), chronic deciduitis, and villitis of unknown etiology compared to twins. Delayed villous maturation and ischemia were more frequently present in monochorionic placentas than in dichorionic. Singletons had a significant lower birthweight and were more often small for gestational age than twins. Multivariate linear regression analysis adjusting for singleton pregnancy, gestational hypertension and placental abnormalities showed that gestational hypertension (β = -114.8), infarct (β = -130.1), decidual necrosis (β = -115.4), fetal hypoxia (β = -59.3) and chronic deciduitis (β = -118.8) were independently associated with lower birthweight. Multivariate regression analysis revealed five independent risk factors of small for gestational age: gestational hypertension (OR 4.4), infarct (OR 3.7), decidual necrosis (OR 2.7), fetal hypoxia (OR 1.9) and villitis (OR 5.2).

DISCUSSION

Singleton pregnancies vary in histological placental abnormality rates from twin pregnancies. This study demonstrated that differences in birthweight and small for gestational age rates between preterm twins and singletons can be attributed to gestational hypertension and histological placental abnormalities.

SARS-CoV-2 Infection and Its Association with Maternal and Fetal Redox Status and Outcomes: A Prospective Clinical Study

Background: The impact of the SARS-CoV-2 viral infection during pregnancy on the fetus can be direct-transmitted through the placenta-and indirect-creating unfavorable conditions for the development of the fetus because of inflammation, micro-thrombosis, and hypercoagulation. Our study aimed to determine the types and frequency of pathohistological changes in placental tissue in SARS-CoV-2-positive pregnant women and to examine the possible role of oxidative stress in the prognosis of the delivery and its maternal and fetal complications. Methods: This prospective clinical study included 50 pregnant women divided into two groups, SARS-CoV-2 positive (COVID-19 group) and SARS-CoV-2 negative (control group), from who we collected demographic, clinical, obstetric, biochemical and pathologic data. Data about the newborn characteristics were also collected, which included anamnestic, clinical, and biochemical data. Results: The values of the superoxide anion radical and index of lipid peroxidation were significantly different in mothers concerning the presence of the SARS-CoV-2 infection, while the levels of the nitric oxide, index of lipid peroxidation, reduced glutathione, and superoxide dismutase were significantly different in the newborns depending on the SARS-CoV-2 infection. Newborn characteristics were similar between groups except for concentrations of IgM antibody. The incidence of pathohistological changes of the FVM type in the COVID-19 group of pregnant women was 46%, while in the control group, the incidence was 18%. Conclusions: This study confirmed the significant impact of the SARS-CoV-2 viral infection on maternal and fetal biochemical parameters and oxidative stress-mediated placental dysfunction. Future studies should be performed with more participants and follow-up neonatal development.

Placental Pathology and Blood Pressure at Age 7: A Longitudinal Discordant Twin Analysis

BACKGROUND

Evidence suggests that the intrauterine environment shapes offspring cardiovascular disease risk. Although placental dysfunction may be an important pathophysiologic pathway, numerous parental and pregnancy characteristics that influence offspring blood pressure are strong confounders of the mechanistic role of the placenta in observational analyses of singletons. Therefore, we leverage twin- and sibling-based comparison designs to determine whether placental pathology is associated with offspring blood pressure at age 7 while mitigating major sources of confounding.

METHODS

Data are from pregnant participants and their offspring in the Collaborative Perinatal Project, a longitudinal pregnancy cohort conducted from 1959 to 1965 in the United States. After delivery, placentas were systematically examined for lesions indicative of maternal vascular malperfusion (MVM) and acute inflammation. Blood pressure was assessed at a follow-up research visit when the offspring were 7 years old. Linear fixed-effects models were used to estimate associations between within-twin or sibling discordance in placental pathology and differences in blood pressure at age 7.

RESULTS

Overall, 193 twin pairs were eligible for inclusion, and 23.3% had placentas discordant for MVM. In a fixed-effect analysis, a twin with high-grade MVM had a higher systolic blood pressure Z score by 0.56 SDs than their co-twin without MVM (95% CI, 0.06-1.05) or a 5.7-mm Hg difference (95% CI, 0.6-10.8). Associations were consistent in a sensitivity analysis restricted to dichorionic twins and in a secondary analysis of 759 MVM-discordant sibling pairs. Acute placental inflammation was not associated with blood pressure at age 7.

CONCLUSIONS

MVM in the placenta is associated with higher offspring blood pressure in mid-childhood, independent of parental and pregnancy characteristics that twins have in common. The findings support the role of the placenta and the intrauterine environment in the developmental origins of cardiovascular health.

Utility of placental biomarkers and fetoplacental Dopplers in predicting likely placental pathology in early and late fetal growth restriction - A prospective study

INTRODUCTION

The aim of this study was to evaluate the association between placental abnormalities, placental biomarkers, and fetoplacental Dopplers in a cohort of pregnancies complicated by fetal growth restriction (FGR). We also ascertained the risk of perinatal mortality, severe neurological morbidity, and severe non-neurological morbidity by type of placental abnormality.

METHODS

This was a prospective cohort study. Multivariable logistic regression was used to evaluate the effect of early vs. late FGR, placental biomarkers and fetoplacental Dopplers on Maternal Vascular Malperfusion (MVM) which was the commonest placental abnormality identified.

RESULTS

There were 161 (53.5 %) early FGR and 140 (46.5 %) late FGR cases. MVM abnormalities were present in 154 (51.2 %), VUE in 45 (14.6 %), FVM in 16 (5.3 %), DVM in 14 (4.7 %) and CHI in 4 (1.3 %) cases. The odds of MVM were higher in early compared to late FGR cohort (OR 1.89, 95%CI 1.14, 3.14, p = 0.01). Low maternal PlGF levels <100 ng/L (OR 2.34, 95%CI 1.27,4.31, p = 0.01), high sFlt-1 level (OR 2.13, 95%CI 1.35, 3.36, p = 0.001) or elevated sFlt-1/PlGF ratio (OR 3.48, 95%CI 1.36, 8.91, p = 0.01) were all associated with MVM. Increased UA PI > 95th centile (OR 2.91, 95%CI 1.71, 4.95, p=<0.001) and mean UtA PI z-score (OR 1.74, 95%CI 1.15, 2.64, p = 0.01) were associated with higher odds of MVM. Rates of severe non-neurological morbidity were highest in the MVM, FVM, and CHI cohorts (44.8 %, 50 %, and 50 % respectively).

CONCLUSION

MVM was the commonest placental abnormality in FGR, particularly in early-onset disease. Low maternal PlGF levels, high sFlt-1 levels, elevated sFlt-1/PlGF ratio, and abnormal fetoplacental Dopplers were also significantly associated with MVM. MVM, FVM, and CHI abnormalities were associated with lower median birthweight, higher rates of preterm birth, operative birth for non-reassuring fetal status, and severe neonatal non-neurological morbidity.

Placenta histology related to flow and oxygenation in fetal congenital heart disease

BACKGROUND

Fetuses with congenital heart defects (CHD) show delayed neurodevelopment, fetal growth restriction (FGR) and placenta related complications. The neurodevelopmental delay may be, partly, attributed to placental factors.

AIM

As both placental development and fetal aortic flow/oxygenation influence neurodevelopment, placentas were compared within fetal CHD groups based on aortic oxygenation and flow, aiming to unravel the true effects in the developmental processes.

STUDY DESIGN

Placental tissues of pregnancies with fetal CHD and healthy controls were selected from biobanks of two Dutch academic hospitals (LUMC, UMCU). Additionally, biometry and Dopplers were assessed.

SUBJECTS

CHD cases with reduced oxygenation (RO) towards the fetal brain were compared to cases with reduced flow (RF) in the aortic arch and healthy controls. Genetic abnormalities, termination of pregnancy, fetal demise and/or multiple pregnancies were excluded.

OUTCOME MEASURES

Histological outcomes were related to fetal Dopplers and biometry. A placenta severity score was used to assess the severity of placental abnormalities per case.

RESULTS

In CHD, significantly more delayed maturation, maternal vascular malperfusion, fetal hypoxia and higher placenta severity scores (median 14 in RO, 14 in RF, 5 in controls, p < 0.001) were observed. Doppler abnormalities (PI UA > p90, PI MCA < p10, CPR < p10) and FGR were more often found in CHD. There were no differences in placental abnormalities, fetal growth and fetal Dopplers between cases with RO and RF.

CONCLUSION

Fetal hemodynamics in the ascending aorta could not be related to placenta characteristics. We hypothesize that placental development influences neurodevelopment in excess of hemodynamics in CHD cases.

CCN1-Mediated Signaling in Placental Villous Tissues after SARS-CoV-2 Infection in Term Pregnant Women: Implications for Dysregulated Angiogenesis

The global spread of SARS-CoV-2 has increased infections among pregnant women. This study aimed to explore placental pathology alterations and angiogenic factor levels in term pregnant women after SARS-CoV-2 infection in a retrospective single-center study. Additionally, we investigated the role and underlying mechanism of the vascular inflammation-promoting, cysteine-rich protein 61 (CYR61/CCN1) in this context. All analyses were performed in term pregnant women infected with or without SARS-CoV-2. The sFlt-1, PlGF, and sEng serum levels were quantified using ELISA. Placental protein expressions were examined by immunoblot and immunostaining. Additionally, the effect of CCN1 protein on SGHPL-5 trophoblast cells was examined. We found that SARS-CoV-2 activated the inflammatory response in pregnant women, leading to pronounced vascular alterations in placental villous tissues. Elevated serum anti-angiogenic factors (sFlt-1, sEng) upon SARS-CoV-2 infection may directly contribute to these pathological changes. Upregulated CCN1 and pNF-κB in placental villous tissues of infected patients are identified as crucial factors in placental alterations. As a conclusion, CCN1 was significantly elevated in the placentas of term pregnant women infected with SARS-CoV-2. By activating a cascade of inflammatory responses, CCN1 induced the production of the anti-angiogenic factors sFlt-1 and sEng, which may lead to abnormal placental vascular architecture.

Outcome-Based Risk Stratification Model for the Diagnosis of Placental Maternal Vascular Malperfusion

The Amsterdam Consensus Statement introduced the term maternal vascular malperfusion (MVM) to group a constellation of findings associated with impaired maternal-placental circulation. In isolation, these findings are relatively common in placentas from normal gestations, and there is uncertainty on how many, and which, are required. We aimed to determine the criteria essential for MVM diagnosis in correlation with obstetrical outcomes. A total of 200 placentas (100 with a reported diagnosis of MVM and 100 controls matched by maternal age and gravida-para-abortus status) were reviewed to document MVM features. Obstetrical outcomes in the current pregnancy were recorded including hypertension, pre-eclampsia with or without severe features, gestational diabetes, prematurity, fetal growth restriction, and intrauterine fetal demise. On univariate logistic regression analysis, adverse outcome was associated with low placental weight (LPW, <10% percentile for gestational age), accelerated villous maturation (AVM), decidual arteriopathy (DA), infarcts (presence and volume), distal villous hypoplasia, and excess multinucleated trophoblast in basal plate ≥2 mm (all P < .01) but not with retroplacental hemorrhage. In a multivariable model DA, infarcts and AVM were significantly associated with adverse outcomes, whereas LPW showed a trend toward significance. A receiver-operating characteristic curve including these 4 parameters showed good predictive ability (area under the curve [AUC], 0.8256). Based on the probability of an adverse outcome, we recommend consistent reporting of DA, AVM, infarcts, and LPW, summarizing them as "diagnostic of MVM" (DA or AVM plus any other feature, yielding a probability of 65%-97% for adverse obstetrical outcomes) or "suggestive of MVM" (if only 1 feature is present, or only 2 features are infarcts plus LPW, yielding a probability of up to 52%). Other features such as distal villous hypoplasia, excess (≥2 mm) multinucleated trophoblast, and retroplacental hemorrhage can also be reported, and their role in MVM diagnosis should be further studied.

Placental pathology in pregnancies with late fetal growth restriction and abnormal cerebroplacental ratio

INTRODUCTION

Late fetal growth restriction (FGR) is associated with mild growth restriction and normal or mild abnormal doppler flows. The cerebroplacental ratio (CPR) has been demonstrated as more sensitive to hypoxia than its individual components in these fetuses. We hypothesized that abnormal CPR in late FGR is reflected in specific placental vascular malperfusion lesions.

METHODS

Retrospective cohort study of late FGR newborns between 2012 and 2022 in a tertiary hospital. Overall, 361 cases were included: 104 with pathological CPR (study group), and 257 with normal doppler flows (control group). The primary outcome was a composite of maternal vascular malperfusion lesions (MVM) and fetal vascular malperfusion lesions (FVM). Secondary outcomes were macroscopic placental characteristics and various obstetrical and neonatal outcomes.

RESULTS

The study group had lower birthweight compared with the normal CPR group (2063.5 ± 470.5 vs. 2351.6 ± 387.4 g. P < 0.0001), higher rates of composite adverse neonatal outcomes (34.2% vs. 22.5%, p < 0.0001), lower mean placental weight (318 ± 71.6 vs. 356.6 ± 76.5 g, p < 0.0001), as well as a higher prevalence of Vascular lesions of MVM (15.3% vs. 5.0%, p = 0.002), villous lesions of FVM (37.5% vs. 24.9%, p = 0.02), and composite FVM lesions (36.5% vs. 25.6%, p = 0.04). On multivariate regression analysis for MVM lesions and composite FVM lesions, abnormal CPR was found as an independent risk factor (aOR 2.17, 95% CI 1.63-4.19, and aOR 1.31, 95% CI 1.09-3.97, respectively).

DISCUSSIONS

Abnormal CPR in late FGR is reflected in placental histopathologic vascular malperfusion lesions, and the incidence of these lesions is higher than in FGR placentas with normal CPR.