Placental Pathology in COVID-19

OBJECTIVES

To describe histopathologic findings in the placentas of women with coronavirus disease 2019 (COVID-19) during pregnancy.

METHODS

Pregnant women with COVID-19 delivering between March 18, 2020, and May 5, 2020, were identified. Placentas were examined and compared to historical controls and women with placental evaluation for a history of melanoma.

RESULTS

Sixteen placentas from patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) were examined (15 with live birth in the third trimester, 1 delivered in the second trimester after intrauterine fetal demise). Compared to controls, third trimester placentas were significantly more likely to show at least one feature of maternal vascular malperfusion (MVM), particularly abnormal or injured maternal vessels, and intervillous thrombi. Rates of acute and chronic inflammation were not increased.The placenta from the patient with intrauterine fetal demise showed villous edema and a retroplacental hematoma.

CONCLUSIONS

Relative to controls, COVID-19 placentas show increased prevalence of decidual arteriopathy and other features of MVM, a pattern of placental injury reflecting abnormalities in oxygenation within the intervillous space associated with adverse perinatal outcomes. Only 1 COVID-19 patient was hypertensive despite the association of MVM with hypertensive disorders and preeclampsia. These changes may reflect a systemic inflammatory or hypercoagulable state influencing placental physiology.

Maternal vascular malperfusion of the placental bed associated with hypertensive disorders in the Boston Birth Cohort

INTRODUCTION

The associations of maternal conditions, before or during pregnancy, with placental lesions have not been adequately studied in populations.

METHODS

In the Boston Birth Cohort, we evaluated associations between three maternal medical conditions (hypertensive disorders [HDs], gestational/pre-gestational diabetes and obesity), and placental histological findings, using a standardized classification system proposed by the Amsterdam Placental Workshop Group. Placental pathology diagnoses and clinical data from 3074 mothers with clinical indications who delivered singleton live births at the Boston Medical Center between October 1998 and November 2013 were evaluated. Associations between each maternal condition and maternal vascular malperfusion (MVM) of the placental bed and its standardized subgroups were examined using multivariate logistic and multinomial regressions.

RESULTS

Women with HDs (chronic hypertension, eclampsia, preeclampsia, HELLP syndrome) had significantly increased odds of MVM lesions when compared to women with no HD (aOR 2.08 95% CI 1.74-2.50), after adjusting for demographics, substance use, diabetes and body mass index. No significant differences in frequencies or aORs were seen in women with and without diabetes, or across body mass index categories. Co-morbid condition patterns that included HDs were more likely to be associated with MVM than those without.

DISCUSSION

Using a standardized classification system, we showed that MVM is strongly and specifically associated with maternal HDs, but not other maternal conditions. Additional studies are needed to confirm and validate our findings, and evaluate the role of maternal vascular lesions of the placental bed in relation to postnatal growth and development of the offspring and effect modifiers.

Preterm birth subtypes, placental pathology findings, and risk of neurodevelopmental disabilities during childhood

INTRODUCTION

Preterm birth (PTB) and in-utero inflammation are recognized risk factors of neurodevelopmental disabilities (NDDs); however, their combined role in NDDs is unknown. We examined the independent and joint association of PTB and placental histological findings with the childhood risk of NDDs (overall and by subgroups including autism spectrum disorder (ASD) and ADHD).

METHODS

We analyzed data from the Boston Birth Cohort, where mother-infant pairs were enrolled at birth and followed from birth onwards. Birth outcomes, placental pathology and NDDs were obtained from electronic medical records. Placental pathology was categorized using a standardized classification system proposed by the Amsterdam Placental Workshop Group.

RESULTS

PTB (all, including spontaneous, medically indicated) was an independent risk factor for NDDs. Placental histological chorioamnionitis (CA) and PTB additively increased the odds of NDDs (aOR: 2.16, 95% CI: 1.37, 3.39), as well as ADHD (aOR: 2.75, 95% CI: 1.55, 4.90), other developmental disabilities (aOR: 1.96, 95% CI: 1.18, 3.25) and possibly ASD (aOR: 2.31, 95% CI: 0.99, 5.39). The above associations were more pronounced in spontaneous than medically indicated PTB. PTB alone in the absence of CA only had a moderate association with ASD and ADHD. Placental maternal vascular malperfusion alone or in combination with PTB was not associated with the risk of NDDs.

DISCUSSION

Our study provided new insights on PTB and NDDs by further considering preterm subtypes and placental histology. We revealed that children of spontaneous PTB along with histological CA were at the highest risk for a spectrum of NDDs.

Placental contribution to neonatal encephalopathy

Placental assessment, although currently underused, can inform our understanding of the etiology and timing of Neonatal Encephalopathy (NE). We review our current understanding of the links between placental dysfunction and NE and how this information may inform clinical decisions, now and in the future, emphasizing the four major placental lesions associated with NE. In addition, we discuss maternal and fetal factors that are hypothesized to contribute to specific placental pathologies, especially innate or acquired thrombophilias. We outline the importance of assessing placenta across trimesters and after delivery. As this field continues to evolve, currently available placental histopathological examination methods may need to be combined with advanced prenatal molecular and imaging assessments of placenta and be applied in well-designed studies in large representative populations to better define the links between placental dysfunction and NE.

Parental ethnicity and placental maternal vascular malperfusion pathology in healthy nulliparous women

INTRODUCTION

Rates of some placental-associated pregnancy complications vary by ethnicity, though the strength of association with underlying placental pathology is presently unknown. Our objective was to determine whether an association between ethnicity and placental pathology occurs in low-risk pregnancies.

METHODS

829 low-risk nulliparous pregnant women were prospectively studied. Data were obtained from standardized obstetrical appointments (clinical history, serum biomarkers, placental ultrasound) and hospital delivery records (pregnancy complications, delivery details and perinatal outcomes). Placental pathology was performed in all subjects using standard criteria.

RESULTS

In our cohort, 72% of women were Caucasian, 14% East Asian, 8% South Asian, 4% Afro-Caribbean and 3% Hispanic women. 81% of couples were concordant (same ethnic background) and 19% discordant (mixed ethnicities). South Asian women had the highest rate of small for gestational age (SGA) birth (customized birthweight <10th percentile) (24.2%), which was associated with the placental features of uteroplacental vascular insufficiency (placental weight <10th percentile with decidual vasculopathy, focal infarction, and/or syncytial knot formation) (p = 0.05). Placental efficiency varied significantly by ethnicity; Caucasian women had the highest efficiency (7.1 ± 1.2) and Afro-Caribbean women the lowest (6.5 ± 0.9) (p < 0.003). Afro-Caribbean women had the highest rate of marginal cord insertion. Placental efficiency, was higher in concordant vs. discordant couples (7.0 ± 1.2 vs. 6.8 ± 1.1; p < 0.05). Placental histopathology was not affected by parental ethnic discordance.

DISCUSSION

Maternal ethnicity influences placental efficiency and relationship between uteroplacental vascular insufficiency and SGA birth, but was not associated with other placental pathologies. Discordant parental ethnicity did not affect the development of placental pathologies or adverse pregnancy outcomes.

Maternal vascular malformation in the placenta is an indicator for fetal growth restriction irrespective of neonatal birthweight

INTRODUCTION

To study the association between placental pathology and neonatal birthweight and outcomes, and whether a combination of first trimester biomarkers and fetal growth velocity can predict placental lesions.

METHODS

The presence of maternal vascular malperfusion (MVM) lesions (Amsterdam criteria) was recorded in a retrospective cohort of singleton pregnancies in the Maastricht University Medical Centre, 2011-2018. First trimester maternal characteristics and PAPP-A, PlGF and sFlt-1 levels were collected. Fetal growth velocities were calculated (mm/week) from 20 to 32 weeks for abdominal circumference, biparietal diameter, head circumference and femur length. Data were compared between neonates with 'small for gestational age' (SGA < p10) and different categories of 'appropriate for gestational age (AGA)': AGAp10-30, AGAp30-50 and AGA > p50 (reference), using one-way ANOVA and post hoc test.

RESULTS

There were significantly more MVM lesions in the SGA group (94.6% p < .0001), but also in the AGAp10-30 (67.3% p < .0001) and AGAp30-50 (41.6% p = 0.002), compared to the reference AGA group (19.3%). The prediction of MVM for a 20% false-positive rate, with maternal characteristics was25.2%. The addition of birthweight percentile gave a prediction of 51.7% for MVM. However adding placental biomarkers and fetal growth velocities (instead of birthweight percentile) to the maternal characteristics, gave a prediction of 81.8% (PPV 49.5%, NPV 53.7%).

DISCUSSION

Placental MVM lesions correlated inversely with birthweight even in AGA neonates, and was associated with slower fetal growth and more adverse outcome in SGA neonates. A combination of first trimester biomarkers and fetal growth velocity had good prediction of placental MVM lesions, as an indicator of fetal growth restriction irrespective of neonatal weight.

The Placenta as a Window to Maternal Vascular Health

Cardiovascular disease remains the leading killer of women, with sex-specific manifestation, mechanisms, and morbidity. Preeclampsia, fetal growth restriction, and a subset of preterm births demonstrate aberrancies in the maternal vessels supplying the placenta and damage to the placental parenchyma consistent with hypoxic/ischemic or oxidative injury. This constellation of findings, maternal vascular malperfusion (MVM) lesions, may hold the key to understanding and identifying the elevated risk for early cardiovascular disease in women who experience adverse pregnancy outcomes. This intriguing possibility has only begun to be examined, but accumulating evidence is compelling and is reviewed here.

The impact of placental massive perivillous fibrin deposition on neonatal outcome in pregnancies complicated by fetal growth restriction

INTRODUCTION

Massive perivillous fibrin deposition (MPDD) is an uncommon placental lesion which has been associated with an increased risk of adverse pregnancy outcome in retrospective series. The purpose of the study was to evaluate the frequency and consequences of MPFD in pregnancies complicated by fetal growth restriction (FGR).

MATERIALS AND METHODS

A cohort study of 355 pregnancies complicated by FGR diagnosed according to standard ultrasonographic criteria, enrolled, followed and delivered at a single obstetric unit. Pathological placental lesions were classified according to the Amsterdam Placental Workshop Consensus. Penalized logistic regression models were used to evaluate the association of MPFD with maternal risk factors, other pathological lesions and neonatal outcome.

RESULTS

The rates of moderate (25-50% of villi) and severe (>50% of villi) MPFD were 8.7% (31/355) and 3.1% (11/355), respectively. Compared to other FGR cases, MPFD pregnancies were characterized by higher placental volume (450 ± 144.5 SD as compared to 412.2 ± 151 cm³,p < 0.001) and lower birthweight/placental weight ratio (5.32 ± 1.53 compared to 6.1 ± 1.52,p < 0.001). The rates of abnormal Doppler ultrasound studies of umbilical and middle cerebral artery were similar in MPFD subjects and controls. After correction for gestational age and birthweight, MPFD was associated with an increased risk of neonatal intraventricular hemorrhage (>grade II) (OR = 5.66,95% CI = 1.69-18.97), sepsis (OR = 5.9, 95% CI = 1.27-27.12), proven necrotizing enterocolitis (OR = 9.84,95% CI = 2.49-38.8) and overall severe adverse neonatal outcome (OR = 5.71,95% CI = 2.05-15.87).

CONCLUSIONS

Moderate-to-severe MPFD was relatively common among FGR pregnancies and was associated with morphometric modifications of placenta and with an increased risk of severe adverse neonatal outcome.

Cord blood alpha klotho is decreased in small for gestational age preterm infants with placental lesions of accelerated aging

BACKGROUND

Intrauterine growth restriction is often accompanied by placental vascular disease, of which histologic maternal vascular malperfusion is prominent. Maternal vascular malperfusion is characterized by accelerated villous maturation consistent with placental aging. Alpha klotho is an anti-aging protein produced by the placenta. We hypothesize that cord blood alpha klotho varies with maternal vascular malperfusion and small for gestational age infants through dysregulated angiogenesis.

METHODS

Nested case-control study of 54 preterm infants (N = 22 small for gestational age infants, 32 appropriate for gestational age infants, mean gestational age = 33.7 ± 2.7 weeks) and validation sample (N = 39) from a longitudinal birth cohort at Prentice Women's Hospital, Chicago, IL. Cord blood alpha klotho was measured via enzyme-linked immunoassay; concentrations were linked to multiplex data of cord blood angiogenic growth factors.

RESULTS

Median cord blood alpha klotho was decreased in small for gestational age infants (1200 [859, 2083] pg/mL) versus controls (3193 [1703, 3963] pg/mL; p < 0.01) and with severe maternal vascular malperfusion (1170 [760, 2645] pg/mL; P < 0.01), consistent with validation sample. Alpha klotho was decreased with maternal vascular malperfusion sublesions signifying accelerated villous maturation, including increased syncytial knots (1230 [805, 3606] pg/mL; p < 0.05) and distal villous hypoplasia (1170 [770, 3390] pg/mL; p < 0.05). Among 15 angiogenic markers, alpha klotho correlated directly with angiopoietin-2 (beta-coefficient = 2.6, p = 0.01).

CONCLUSIONS

Cord blood alpha klotho is decreased with small for gestational infants and maternal vascular malperfusion sublesions of accelerated placental villous maturation, and correlated with angiopoietin-2. Alpha klotho may play a role in vascular-mediated accelerated placental aging leading to intrauterine growth restriction.

Life After Amsterdam: Placental Pathology Consensus Recommendations and Beyond

The Amsterdam Placental Workshop Group Consensus Statement on Sampling and Definitions of Placental Lesions has become widely accepted and is increasingly used as the universal language to describe the most common pathologic lesions found in the placenta. This review summarizes the most salient aspects of this seminal publication and the subsequent emerging literature based on Amsterdam definitions and criteria, with emphasis on publications relating to diagnosis, grading, and staging of placental pathologic conditions. We also provide an overview of the recent expert recommendations on the pathologic grading of placenta accreta spectrum, with insights on their clinical context. Finally, we discuss the emerging entity of SARS-CoV2 placentitis.

Placental pathology from COVID-19-recovered (nonacute) patients

Placental pathology can identify characteristic features of specific infectious pathogens. The histopathology of acute SARS-CoV-2 placental infection and exposure without infection has been well described. However, whether the characteristic placental pathology persists after the acute phase of the infection is less clear. We retrospectively identified 67 COVID-19-recovered pregnant patients who had placental pathology available. After reviewing the gross and histopathology, we categorized the findings and studied the placentas for evidence of chronic infection by immunohistochemistry for the spike protein of the virus. We found these placentas showed significantly increased prevalence of maternal and a trend towards significance of fetal vascular malperfusion when compared to a control group of placentas examined for the sole indication of maternal group B streptococcal colonization. None of the COVID-19-recovered placentas showed expression of the viral spike protein; therefore, we found no evidence of persistent infection of the placenta in women with a history of COVID-19 during their pregnancy. We conclude that recovery from a SARS-CoV-2 infection during pregnancy puts the pregnancy at risk for specific pathology.

The association between first trimester placental biomarkers and placental lesions of maternal vascular malperfusion

INTRODUCTION

Abnormal levels of first trimester placental biomarkers are associated with the development of placental syndrome (PS). However, prediction performance is moderate, possibly explained by the clinical heterogeneity of PS. Aim of this study is to investigate the association between first trimester biomarkers and the presence of maternal vascular malperfusion (MVM), as a marker for placental insufficiency.

METHODS

This retrospective study included 195 women with available first trimester blood sample and placenta histological sections for examination at the Maastricht University Medical Centre. Women were divided into 4 groups, based on the presence of having MVM lesions and/or PS. Levels of PAPP-A, PlGF and sFlt-1 were measured and MVM lesions were classified according to the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

MVM occurrence was observed in 32% of the uncomplicated pregnancies. Women with MVM (regardless of the PS) had lower levels of PAPP-A (p = 0.038) and sFLt-1 (p = 0.006), and a non-significant trend for lower PlGF and sFlt-1/PlGF ratio compared to women without MVM. Low PAPP-A levels individually and in combination with the presence of PS was significantly associated with MVM lesions (aOR = 3.0 and 6.1, respectively), as did the combination of low PlGF levels and PS (aOR = 4.6). In women with PS, having MVM increased the incidence of fetal growth restriction, small for gestational age neonates, lower birthweight and adverse neonatal outcome.

DISCUSSION

Our findings suggest that MVM lesions were found to be associated with increased obstetric risks due to early placental dysfunction that can potentially be predicted by the use of first trimester biomarkers.

Patterns of placental pathology associated with preeclampsia

INTRODUCTION

Maternal vascular malperfusion (MVM) is commonly observed in early onset preeclampsia, but less prevalent in late onset preeclampsia. The purpose of our analysis was to investigate patterns of placental pathology in preeclampsia.

METHODS

Electronic health records for all singleton livebirths from 2009 to 2018 at a single institution with a diagnosis of preeclampsia were obtained. Text searching was used to obtain placental data from pathology reports, including lesions of MVM, fetal vascular malperfusion (FVM), chronic inflammation (CI), and acute inflammation (AI). Placental pathology was compared based on timing of delivery and latent class analysis (LCA) was used to investigate subtypes of preeclampsia based on 22 placental variables.

RESULTS

728 patients were included in the analysis. Prevalence of MVM decreased with advancing gestation (95.4% at <34 weeks, 69.8% at 34-36 weeks, and 50%, ≥37 weeks; p < 0.01). LCA identified five classes based on placental pathology: (1) high grade MVM, (2) CI and FVM, (3) low grade MVM, (4) AI, (5) other. Preterm birth varied across the classes (p < 0.01), with the highest prevalence observed among the classes characterized by MVM (high grade: 87.6%; low grade: 63.0%) and the lowest prevalence among the class characterized by AI (23.5%).

DISCUSSION

Placental pathology in preeclampsia differs based on gestational age at delivery with MVM seen in nearly all early onset preeclampsia cases. Latent classes largely grouped by previously defined patterns of placental injury (MVM, CI, FVM, AI), and again revealed the highest likelihood of preterm birth in classes characterized by MVM. Results suggest there may be multiple mechanisms leading to the clinical manifestations of preeclampsia.

Wave reflections in the umbilical artery measured by Doppler ultrasound as a novel predictor of placental pathology

Background

The umbilical artery (UA) Doppler pulsatility index is used clinically to detect elevated feto-placental vascular resistance. However, this metric is confounded by variation in fetal cardiac function and is only moderately predictive of placental pathology. Our group developed a novel ultrasound methodology that measures wave reflections in the UA, thereby isolating a component of the Doppler signal that is specific to the placenta. The present study examined whether wave reflections in the UA are predictive of placental vascular pathology.

Methods

Standard clinical Doppler ultrasound of the UAs was performed in 241 pregnant women. Of these, 40 women met narrowly defined preset criteria for the control group, 36 had maternal vascular malperfusion (MVM) and 16 had fetal vascular malperfusion (FVM). Using a computational procedure, the Doppler waveforms were decomposed into a pair of forward and backward propagating waves.

Findings

Compared to controls, wave reflections were significantly elevated in women with either MVM (p<0.0001) or FVM pathology (p = 0.02). In contrast, the umbilical and uterine artery pulsatility indices were only elevated in the MVM group (p<0.0001) and there were no differences between women with FVM and the controls.

Interpretation

The measurement of wave reflections in the UA, combined with standard clinical ultrasound parameters, has the potential to improve the diagnostic performance of UA Doppler to detect placental vascular pathology. Identifying women with FVM pathology is particularly challenging prenatally and future investigations will determine if women at risk of this specific placental disease could benefit from this novel diagnostic technique.

Fetal foot length at delivery as a tool for determining gestation length in non-macerated stillbirths

OBJECTIVE

To assess whether fetal foot length at autopsy could reliably indicate gestation duration at stillbirth and the effects of maceration on this method.

METHODS

The present cross-sectional secondary analysis was part of the Safe Passage Study; all Safe Passage Study participants who experienced a stillbirth at Tygerberg Academic Hospital, Cape Town, South Africa, between August 1, 2007, and January 31, 2015, were eligible to participate. After providing written informed consent for autopsy, the duration of gestation calculated using early ultrasonography and fetal foot length were compared.

RESULTS

There were 69 fetal autopsies included in the present study; placental histology was available for 65. Generally, the gestation length calculated from the first ultrasonography scan correlated well with that calculated from the fetal foot length (Spearman correlation=0.85). However, significant differences were found in the gestation lengths calculated when the fetus was macerated (P<0.001), or when umbilical cord pathology (P<0.001) or maternal vascular malperfusion (P<0.001) was the cause of fetal death.

CONCLUSION

Foot length at stillbirth was a good indicator of gestation length; however, it was a weaker indicator if fetal maceration had occurred.

Macroscopic lesions of maternal and fetal vascular malperfusion in stillborn placentas: Diagnosis in the absence of microscopic histopathological examination

INTRODUCTION

Lesions of maternal vascular malperfusion (MVM) and fetal vascular malperfusion (FVM) are common in placentas associated with both stillbirth and live birth. The objective of this study was to identify lesions present more commonly in stillborn placentas and those most indicative of MVM and FVM without microscopic pathologic evaluation.

METHODS

Data were derived from the Stillbirth Collaborative Research Network. Lesions were identified according to standard protocols published previously and categorized as either MVM or FVM according to the Amsterdam Placental Workshop Group Consensus Statement and macroscopic "umbilical cord at risk" findings. Multivariate logistic regression was used to determine the odds of stillbirth with macroscopic findings of MVM or FVM.

RESULTS

595 stillbirths and 1,305 live births were analyzed. FVM lesions (85.2%) were marginally more common (though not statistically different) in stillbirths compared to MVM lesions (81.3%). Macroscopic findings of both MVM and FVM were more common in stillbirths versus livebirths (p < 0.001). Odds ratios of macroscopic MVM and FVM lesions for stillbirth, adjusted for gestational age at delivery, maternal race (minority), ethnicity (Hispanic), age, and history of hypertension or diabetes, were 1.48 (95% CI 1.30-1.69) and 1.34 (95% CI 1.18-1.53), respectively.

DISCUSSION

Macroscopic features of MVM and FVM are associated with higher odds of stillbirth versus live birth even when controlled for gestational age and maternal factors, which may be a useful clue in determining the pathophysiology of these events. This information is also useful for pathologists when microscopic examination is not available.

Pathologic Basis for the Definition of Discordant Growth in Dichorionic Twins

OBJECTIVE

The aim of the current study was to identify the optimal cutoff that should define discordance in dichorionic twin gestations through correlation with abnormal placental pathology as a specific measure of fetal growth restriction of the smaller twin.

METHODS

We performed a retrospective cohort study of all women with dichorionic twin pregnancies who gave birth in a single center between 2002 and 2015. We investigated the association between the level of growth discordance and maternal vascular malperfusion (MVM) pathology in the placenta of the smaller twin, with and without adjustment for whether the smaller twin is small for gestational age (SGA).

RESULTS

A total of 1,198 women with dichorionic twin gestation met the study criteria. The rate of MVM pathology in the placenta of the smaller twin increased with the level of discordance and was most obvious for discordance ≥25% (rate of MVM 12.0% compared with 2.8% in cases with discordance <10%, adjusted relative risk [aRR] 3.71, 95% confidence interval [CI] 1.97-6.99). When the analysis was adjusted for SGA of the smaller twin, discordance was independently associated with MVM pathology only when growth discordance was ≥25% (aRR 2.18, 95%-CI 1.01-4.93), while SGA was strongly associated with MVM pathology irrespective of the level of discordance.

CONCLUSION

Our findings suggest that discordant growth in dichorionic twins should raise the concern of fetal growth restriction of the smaller twin, irrespective of whether the smaller twin is SGA, only when the discordance s ≥25%. The association of lower levels of discordance with abnormal placental pathology is mainly driven by the confounding effect of SGA of the smaller twin.

Placental Histological Features and Neurodevelopmental Outcomes at Two Years in Very-Low-Birth-Weight Infants

BACKGROUND

We evaluated the rates of placental pathologic lesions and their relationship with two-year neurodevelopmental outcomes in very-low-birth-weight (VLBW) infants.

METHODS

This is a cohort observational study comprising 595 VLBW infants during 2007 to 2015. Neurodevelopmental assessment was carried out at 24 months corrected age.

RESULTS

In univariate analysis the rates of survival with normal neurodevelopmental outcomes were lower in pregnancies with severe histologic chorioamnionitis (38 of 43, 88.4% when compared with 305 of 450, 67.8%), severe maternal vascular malperfusion (MVM) (17 of 37, 45.9% when compared with 326/492, 66.3%), and intravillous hemorrhage (37 of 82, 45.1% when compared with 306 of 449, 68.1%). In logistic models, severe MVM (adjusted odds ratio [adj. OR] = 0.45, 95% confidence interval [CI] = 0.22 to 0.92), severe fetal vascular malperfusion (FVM) (adj. OR = 0.46, 95% CI = 0.22 to 0.45), and intravillous hemorrhage (adj. OR = 0.38, 95% CI = 0.22 to 0.62) were associated with lower rates of infant survival with normal neurodevelopmental outcome. FVM (adj. OR = 0.46, 95% CI = 0.21 to 0.97) and intravillous hemorrhage (adj. OR = 0.37, 95% CI = 0.22 to 0.62) were also the only placental lesions that were independent predictors of a lower rate of intact survival in stepwise analysis for prognostic factors of the entire cohort.

CONCLUSIONS

Placental pathologic findings such as severe MVM, FVM, and intravillous hemorrhage are significant predictors of neonatal survival and subsequent adverse neurodevelopmental outcomes. Data on the placental pathology could be useful in the neurodevelopmental follow-up of VLBW infants.

Placental pathologic features in obesity

INTRODUCTION

Obesity in pregnancy is associated with adverse long-term consequences both in the mother and in offspring. Maternal obesity induces a metabolic-inflammatory state that could impact on placental function and could mediate the adverse outcomes. The purpose of this study was to compare the major placental histological characteristics of non-diabetic obese women to lean controls, focusing on uncomplicated pregnancies.

METHODS

Prospective case-control study comparing placental histopathological features between 122 non-diabetic obese women and 185 non-obese controls. The analysis was performed on overall subjects, then uncomplicated pregnancies from both groups were analyzed. Placenta pathologic findings were recorded according to standard classification.

RESULTS

Both in overall analysis and among the subset of subjects with an uncomplicated pregnancy, obese subjects had higher risks of maternal vascular malperfusion (MVM) (respectively OR=2.2, 95%CI =1.3-3.7 and OR=4.2, 95%CI=2.1-8.5), fetal vascular malperfusion (FVM) (respectively OR=6.3, 95%CI=3.1-12.5 and OR=7.2, 95%CI=3-17.2), maternal and fetal inflammatory response placental lesions and villitis (VUE) (respectively OR=2.5, 95%CI=1.1-5.6 and OR=10.8, 95%CI=3.3-35.3) compared to controls. Among uncomplicated pregnancies and after adjustment for confounders, first trimester BMI was significantly associated with overall MVM, overall FVM, maternal inflammatory, fetal inflammatory response and VUE.

DISCUSSION

Placentas from obese women showed a significantly higher risk of maternal and fetal vascular and inflammatory placental lesions, both in overall population and in the subgroup with uncomplicated pregnancies. The metabolic and inflammatory dysfunctions typical of obesity could have an impact on placental development and function, which could be a mediator of the detrimental effects of obesity on pregnancy outcome and on future health of the offspring.

Maternal folate status and placental vascular malperfusion: Findings from a high-risk US minority birth cohort

INTRODUCTION

Maternal folate deficiency was associated with preeclampsia (PE) and PE was associated with placental maternal vascular malperfusion (MVM). However, no study has examined the association of maternal folate status with placental MVM.

METHODS

We examined the association of maternal folate status and placental MVM in the Boston Birth Cohort. Primary exposure variables were maternal self-reported multivitamin supplement (<2, 3-5, >5 times/week) per trimester; and plasma folate levels (nmol/L) after birth. Primary outcome was presence/absence of placental MVM defined by the Amsterdam Placental Workshop Group standard classification. Covariates included demographics, chronic hypertension, clinically diagnosed PE, eclampsia and HELLP syndrome, gestational and pre-gestational diabetes, overweight/obesity, maternal cigarette smoking and alcohol use. Associations between folate and placental MVM were evaluated using multivariate logistic regressions.

RESULTS

Of 3001 mothers in this study, 18.8% of mothers had PE, 37.5% had MVM. Mothers with the lowest self-reported frequency of folate intake had the highest risk of MVM (OR 1.45, 95% CI 1.03-2.05), after adjusting for the covariates. Consistently, among a subset of 939 mothers with plasma folate levels, folate insufficiency was associated with increased risk of MVM (OR 1.65, 95% CI 1.03-2.63), after adjusting for the covariables. As expected, mothers with low folate and placental MVM had highest rates of PE compared to those of high folate and no MVM (p < 0.001).

DISCUSSION

In this high-risk birth cohort, low maternal folate status was associated with increased risk of placental MVM. Further investigation should explore the association between folate status, placental findings and the great obstetrical syndrome.

Placental pathologic features in thyroid autoimmunity

INTRODUCTION

Data on placental pathologic features associated with thyreoperoxidase antibodies (TPO Ab) and/or hypothyroidism are limited. The objective of the study was to analyze placental pathologic features of women with TPO Ab positivity.

METHODS

Prospective case-control observational study of pregnancy outcome among women screened for TPO Ab positivity and/or isolated hypothyroidism (TSH>4mU/L) during the first trimester of pregnancy. Placenta pathologic findings were recorded according to standard classification.

RESULTS

The overall rates of TPO Ab positivity and isolated hypothyroidism with negative TPO Ab were 9.6% (86/899) and 2.7% (24/899), respectively. Among TPO Ab positive cases, 77.9% (67/86) and 22.1% (19/86) had TSH ≥2.5mU/L or <2.5mU/L, respectively. Compared to controls, mean first and second trimester uterine artery Doppler pulsatility indices (PI) were higher, placental volume and area were lower among cases with TSH≥2.5mU/L. The rates of fetal growth restriction (FGR)/small for gestational age (SGA) (20/67 versus 8/110, Adjusted Odds Ratio (AdjOR) = 10.8,95%CI = 2.7-44), placental pathological features suggesting decidual vasculopathy (37/67 versus 27/110, AdjOR = 2.7,95%CI = 1.1-6.8) or severe maternal vascular malperfusion (MVM) (22/67 versus 9/110, AdjOR = 5.8,95%CI = 1.6-20.1) were higher among cases with TSH ≥2.5mU/L than in controls. Similar results were obtained comparing overall TPO Ab positive subjects to controls. The increased risk of defective placentation and FGR associated with TPO Ab was independent of simultaneous presence of antinuclear antibodies (ANA) and TSH concentration.

DISCUSSION

First trimester TPO Ab positivity was associated with increased rates of abnormal uterine artery Doppler PI and placental features of MVM. This association was independent of TSH concentration and presence of ANA.

Spontaneous preterm birth with placental maternal vascular malperfusion is associated with cardiovascular risk in the fifth decade of life

Women with a history of spontaneous preterm birth (SPTB) have a mildly elevated cardiovascular risk (CVR) later in life and women with a history of preeclampsia have a highly elevated CVR. In placentas of women with preeclampsia pathological signs of maternal vascular malperfusion (MVM) are often seen. These signs of MVM are also seen in a substantial part of the placentas of women with SPTB. We therefore hypothesize that in women with a history of SPTB, the subgroup with placental MVM has an elevated CVR. This study is a secondary analysis of a cohort study including women 9-16 years after a SPTB. Women with pregnancy complications known to be associated with CVR were excluded. The primary outcome was hypertension defined as blood pressure ≥ 130/80 mmHg and/or treatment with antihypertensive medication. Secondary outcomes were mean blood pressure, anthropometrics, blood measurements including cholesterol and HbA1c, and creatinine in urine. Placental histology was available in 210 (60.0%) women. MVM was found in 91 (43.3%) of the placentas, most often diagnosed by the presence of accelerated villous maturation. Hypertension was diagnosed in 44 (48.4%) women with MVM and in 42 (35.3%) women without MVM (aOR 1.76, 95% CI 0.98 - 3.16). Women with a SPTB and placental MVM showed significantly higher mean diastolic blood pressure, mean arterial pressure and HbA1c approximately 13 years after delivery, compared to women with a SPTB without placental MVM. We therefore conclude that placental malperfusion in women with a SPTB might differentiate in CVR later in life.

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.

Placental lesions attributed to shallow implantation, excess extravillous trophoblast and decidual hypoxia: Correlation with maternal vascular malperfusion and related obstetric conditions

INTRODUCTION

Maternal vascular malperfusion (MVM) is one of four main patterns of placental injury defined by the Amsterdam consensus statement and is associated with adverse fetal and maternal outcomes. Laminar decidual necrosis (DLN), extravillous trophoblast islands (ETIs), placental septa (PS), and basal plate multinucleate implantation-type trophoblasts (MNTs) are lesions attributed to decidual hypoxia, excess trophoblast, and shallow implantation, but are not included in the current MVM diagnostic criteria. We aimed to investigate the relationship between these lesions and MVM.

METHODS

A case-control model was used to evaluate for DLN, ETIs, PS, and MNTs. Placentas with MVM on pathologic examination (defined as ≥2 related lesions) constituted the case group, and maternal age- and GPA-status-matched placentas with less than 2 lesions constituted the control group. MVM-related obstetric morbidities were recorded, including hypertension, preeclampsia, and diabetes. These were correlated with the lesions of interest.

RESULTS

200 placentas were reviewed: 100 MVM cases and 100 controls. MNTs and PS showed significant enrichment in the MVM group (p < .05). Furthermore, larger foci of MNTs (>2 mm linear extent) were significantly associated with chronic or gestational hypertension (OR = 4.10; p < .05) and preeclampsia (OR = 8.14; p < .05). DLN extent correlated with placental infarction, but DLN and ETIs (including size and number) lacked association with MVM-related clinical conditions.

DISCUSSION

As a marker of abnormally shallow placentation and related maternal morbidities, MNT merits inclusion within the MVM pathologic spectrum. Consistent reporting of MNTs >2 mm in size is recommended, as these lesions correlate with other MVM lesions and MVM-predisposing morbidities. Other lesions, particularly DLN and ETI, lacked such association questioning their diagnostic utility.

Clinicopathologic correlation and interdependence of basic patterns of placental injury

Placental lesions rarely occur in isolation and placental lesion multiplicity is associated with poorer pregnancy outcome than that of isolated lesions. As little is known about mutual relations of various patterns of placental injury simultaneously occurring in the same placentas, particularly in relation to gestational age, this retrospective observational analysis was undertaken to study those in a population of 2486 cases of the second half high-risk pregnancy dominated by fetal congenital anomalies. To this end, 23 independent clinical and 48 placental phenotypes were statistically compared among 6 basic patterns of placental injury: Group 1: acute inflammation, Group 2: chronic inflammation, Group 3: maternal vascular malperfusion, Group 4: fetal vascular malperfusion, large vessel, Group 5: fetal vascular malperfusion, distal villous, and Group 6: shallow placental implantation. All cases had E cadherin/CD34 immunostaining performed for the diagnosis of recent fetal vascular malperfusion. There was a significant overlap among the studied patterns and lesions of placental injury. Placental distal villous fetal vascular malperfusion and acute inflammation was most frequently statistically significantly associated with abnormal clinical conditions, while lesions of distal villous fetal vascular malperfusion and maternal vascular malperfusion with other placental lesions/patterns of injury. The double immunostaining was responsible for the fetal vascular malperfusion being the most common type of placental injury in this population of placentas. The acute inflammation best correlated with clinical condition in preterm pregnancy and distal villous fetal vascular malperfusion at term. Maternal vascular malperfusion plus the above two patterns of placental injury correlated best with other placental phenotypes in mid third trimester.