Pregnancy outcome and placental pathology in small for gestational age neonates in relation to the severity of their growth restriction

Evolutionary perspective of uteroplacental malperfusion: subjacent insult common to most pregnancy complications

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Histopathologic and Transcriptomic Profiling Identifies Novel Trophoblast Defects in Patients With Preeclampsia and Maternal Vascular Malperfusion

Preeclampsia (PE) is a heterogeneous disease for which the current clinical classification system is based on the presence or absence of specific clinical features. PE-associated placentas also show heterogeneous findings on pathologic examination, suggesting that further subclassification is possible. We combined clinical, pathologic, immunohistochemical, and transcriptomic profiling of placentas to develop integrated signatures for multiple subclasses of PE. In total, 303 PE and 1388 nonhypertensive control placentas were included. We found that maternal vascular malperfusion (MVM) in the placenta was associated with preterm PE with severe features and with small-for-gestational-age neonates. Interestingly, PE placentas with either MVM or no histologic pattern of injury showed a linear decrease in proliferative (p63+) cytotrophoblast per villous area with increasing gestational age, similar to placentas obtained from the nonhypertensive patient cohort; however, PE placentas with fetal vascular malperfusion or villitis of unknown etiology lost this phenotype. This is mainly because of cases of fetal vascular malperfusion in placentas of patients with preterm PE and villitis of unknown etiology in placentas of patients with term PE, which are associated with a decrease or increase, respectively, in the cytotrophoblast per villous area. Finally, a transcriptomic analysis identified pathways associated with hypoxia, inflammation, and reduced cell proliferation in PE-MVM placentas and further subclassified this group into extravillous trophoblast-high and extravillous trophoblast-low PE, confirmed using an immunohistochemical analysis of trophoblast lineage-specific markers. Our findings suggest that within specific histopathologic patterns of placental injury, PE can be subclassified based on specific cellular and molecular defects, allowing the identification of pathways that may be targeted for diagnostic and therapeutic purposes.

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

INTRODUCTION

Placental vascular disease, characterized by Maternal Vascular Malperfusion (MVM) lesions, is considered to be the underlying cause of pregnancy complications. Aim is to evaluate the relationship between the cumulative number of MVM lesion types, and adverse pregnancy- and neonatal outcomes.

METHODS

This retrospective cohort study included 272 women with singleton gestations who gave birth at a Dutch tertiary hospital between 2017 and 2018 with available placental histopathology reports. Analyzed according to the Amsterdam Placental Workshop Group Consensus Statement, placentas were divided into groups based on the cumulative number of MVM lesions: no lesions (n = 124), 1-2 types (n = 124) and 3-5 types of lesions (n = 24).

RESULTS

The proportion of placenta syndrome (PS) was highest (95.8%) in the 3-5 MVM lesions group (p < 0.001). The presence of MVM lesions was highly associated with PS during pregnancy (aOR 6.81, 95% CI 3.76-12.33). Furthermore, every additional type of MVM lesion corresponded with a threefold increased odds for the occurrence of PS (aOR 3.00, 95% CI 2.10-4.29). The group with 3-5 types of MVM lesions showed the highest incidence of adverse neonatal outcomes, lower mean birth weight, prolonged hospitalization, NICU admissions and neonatal deaths (aOR 6.47, 95% CI 0.33-127.68), corresponding with a fourfold increased odds for the occurrence of neonatal death for every additional MVM lesion (aOR 4.19, 95% CI 1.39-12.68).

DISCUSSION

A higher number of MVM lesion types is strongly associated with an increased incidence of adverse pregnancy- and neonatal outcomes, indicating that guidelines should focus also on the amount of MVM lesion types for the monitoring/management of subsequent pregnancies.

Recent research on the influence of intrauterine growth restriction on the structure and function of the nervous system

Intrauterine growth restriction (IUGR) is caused by many factors, and most newborns with IUGR are small for gestational age (SGA). SGA infants have a relatively high risk of death and disease in the perinatal period, and the nervous system already has structural changes in the uterus, including the reduction of brain volume and gray matter volume, accompanied by abnormal imaging and pathological changes. IUGR fetuses undergo intrauterine blood flow redistribution to protect brain blood supply, and there are still controversies over the clinical effect of brain protection mechanism. SGA infants have a relatively high risk of abnormal cognitive, motor, language, and behavioral functions in the neonatal period and childhood, and preterm infants tend to have a higher degree of neurological impairment than full-term infants. Early intervention may help to improve the function of the nervous system.

The thrifty phenotype hypothesis: The association between ultrasound and Doppler studies in fetal growth restriction and the development of adult disease

Barker pioneered the idea that the epidemic of coronary heart disease in Western countries in the 20th century, which paradoxically coincided with improved standards of living and nutrition, has its origin in fetal life. Indeed, there is substantial evidence associating low birthweight because of fetal growth restriction with an increased risk of vascular disease in later adult life. These conclusions led to the second part of the Barker hypothesis, the thrifty phenotype, in which adaptation to undernutrition in fetal life leads to permanent metabolic and endocrine changes. Such changes are beneficial if the undernutrition persists after birth but may predispose the individual to obesity and impaired glucose tolerance if conditions improve. The hypothesis assumes that a poor nutrient supply during a critical period of in utero life may "program" a permanent structural or functional change in the fetus, thereby altering the distribution of cell types, gene expression, or both. The fetus, in response to placental undernutrition and to maintain sufficient vascular supply to the brain, decreases resistance to blood flow in the middle cerebral artery. Simultaneously, because of the limited blood supply to the fetus, the arterial redistribution process is accompanied by increased resistance to flow to other fetal vital organs, such as the heart, kidneys, liver, and pancreas. It may explain why individuals exposed to ischemic changes in utero develop dyslipidemia, lower nephron number, and impaired glucose tolerance, all factors contributing to metabolic syndrome later in life. Nevertheless, support for the hypotheses comes mainly from studies in rodents and retrospective epidemiologic studies. This review focused on ultrasound and Doppler studies of human fetal growth restriction in several fetal organs: the placenta, fetal circulation, brain, heart, kidneys, adrenal glands, liver, and pancreas. Support for the hypothesis was provided by animal studies involving conditions that create fetuses with growth restriction with effects on various fetal organs and by human studies that correlate impaired fetal circulation with the in utero development and function of fetal organs.

FIGO (international Federation of Gynecology and obstetrics) initiative on fetal growth: best practice advice for screening, diagnosis, and management of fetal growth restriction

Fetal growth restriction (FGR) is defined as the failure of the fetus to meet its growth potential due to a pathological factor, most commonly placental dysfunction. Worldwide, FGR is a leading cause of stillbirth, neonatal mortality, and short- and long-term morbidity. Ongoing advances in clinical care, especially in definitions, diagnosis, and management of FGR, require efforts to effectively translate these changes to the wide range of obstetric care providers. This article highlights agreements based on current research in the diagnosis and management of FGR, and the areas that need more research to provide further clarification of recommendations. The purpose of this article is to provide a comprehensive summary of available evidence along with practical recommendations concerning the care of pregnancies at risk of or complicated by FGR, with the overall goal to decrease the risk of stillbirth and neonatal mortality and morbidity associated with this condition. To achieve these goals, FIGO (the International Federation of Gynecology and Obstetrics) brought together international experts to review and summarize current knowledge of FGR. This summary is directed at multiple stakeholders, including healthcare providers, healthcare delivery organizations and providers, FIGO member societies, and professional organizations. Recognizing the variation in the resources and expertise available for the management of FGR in different countries or regions, this article attempts to take into consideration the unique aspects of antenatal care in low-resource settings (labelled “LRS” in the recommendations). This was achieved by collaboration with authors and FIGO member societies from low-resource settings such as India, Sub-Saharan Africa, the Middle East, and Latin America.

Formulating a Meaningful and Comprehensive Placental Phenotypic Classification

INTRODUCTION

While many placental lesions have been identified and defined, the significance of multiple overlapping lesions has not been addressed. The purpose of our analysis was to evaluate overlapping patterns of placental pathology and determine meaningful phenotypes associated with adverse birth outcomes.

METHODS

Placental pathology reports were obtained from a single hospital between 2009 and 2018. Placental lesions were grouped into four major categories: acute inflammation (AI), chronic inflammation (CI), maternal vascular malperfusion (MVM), and fetal vascular malperfusion (FVM). Within each category, lesions were classified as not present, low grade or high grade. Combinations of pathologies were evaluated in relation to preterm birth (<37 weeks) and small for gestational age (SGA) infant (birthweight <10th percentile).

RESULTS

During the study period, 19,027 placentas were reviewed by pathologists. Results from interaction models indicate that MVM and MVM in combination with CI and/or FVM are associated with the greatest odds of SGA infant and PTB. When incorporating grade, we identified 21 phenotype groups, each with characteristic associations with the SGA infant and patterns of PTB.

DISCUSSION

We have developed a comprehensive and meaningful placental phenotype that incorporates severity and multiplicity of placental lesions. We have also developed a web application to facilitate phenotype determination (https://placentaexpression.shinyapps.io/phenotype).

Perinatal Arterial Ischemic Stroke in Fetal Vascular Malperfusion: A Case Series and Literature Review

Fetal vascular malperfusion includes a continuum of placental histologic abnormalities increasingly associated with perinatal brain injury, namely arterial ischemic stroke. Here, we describe the clinical-neuroimaging features of 5 neonates with arterial ischemic stroke and histologically proved fetal vascular malperfusion. All infarcts involved the anterior territories and were multiple in 2 patients. In 2 neonates, there were additional signs of marked dural sinus congestion, thrombosis, or both. A mixed pattern of chronic hypoxic-ischemic encephalopathy and acute infarcts was noted in 1 patient at birth. Systemic cardiac or thrombotic complications were present in 2 patients. These peculiar clinical-radiologic patterns may suggest fetal vascular malperfusion and should raise the suspicion of this rare, underdiagnosed condition carrying important implications in patient management, medicolegal actions, and future pregnancy counseling.

Placental histopathology in sickle cell disease: A descriptive and hypothesis-generating study

INTRODUCTION

Abnormal placental development is a unifying factor amongst many adverse pregnancy outcomes (APOs) in Sickle Cell Disease (SCD). Our aim was to describe placental histopathologic findings in women with SCD and their relationship with APOs, and to explore the association between antenatal sonographic findings and placental pathology.

METHODS

Retrospective single-centre case series of all pregnant women with SCD (January 2000-December 2017), pregnancy beyond 20 weeks' gestation, and available placenta histopathology. APOs included intrauterine fetal death, early neonatal death, preterm birth, small for gestational age, and hypertensive disorders of pregnancy. Review of images for mid-pregnancy ultrasound and one proximal to delivery was completed, blinded to clinical outcomes and histopathology results. Gross and histopathologic findings were reviewed and characterized per published classification.

RESULTS

Of 72 placentas, abnormalities were present in 69%, with Maternal Vascular Malperfusion (MVM) noted in 40%. APOs were encountered in 61% overall and in 79% of those with MVM. Neither SCD genotype nor severe maternal anemia had an influence on histopathologic placental features. Presence of high-resistance uterine artery waveforms at mid-trimester ultrasound was strongly associated with APOs and with abnormal findings on placental histopathology, most notably MVM. MVM was strongly associated with small for gestational age infants, preterm birth, and stillbirth.

DISCUSSION

MVM is the predominant lesion in placentas of women with SCD and is strongly associated with APOs. Mid-trimester ultrasound can identify a subset of women at risk. Future research into advanced imaging modalities to aid in antenatal diagnosis alongside investigations of potentially beneficial therapies is needed.

Placental abnormalities differ in small for gestational age neonates in relation to their prenatal sonographic abdominal circumference measurements

Background: Antenatal detection of abdominal circumference (AC) <10th percentile, among small for gestational age (SGA) neonates, probably reflects the severity of their growth restriction. We aimed to study neonatal outcome and placental pathology among SGA neonates in correlation to their AC measurements.Methods: Maternal and neonatal computerized medical records and placental histopathology reports of all SGA neonates, (neonatal birth-weight ≤10th percentile), born between 24 and 42 weeks, during 2015-2018 were reviewed. Included cases with fetal biometric measurements conducted up to 7 days prior labor. Results were compared between cases with sonographic antenatal AC <10th percentile and neonates with sonographic antenatal AC ≥10th percentile. Placental lesions were classified according to "Amsterdam" Placental workshop criteria.Results: The AC <10th percentile group (n = 148) was characterized by higher rate of nulliparity (p = .003), and induction of labor (p = .009), as compared to the AC ≥10th percentile group (n = 41). There were no between groups differences in the rate of maternal BMI (kg/m²), hypertensive disorders, diabetes or smoking. Neonatal hypoglycemia was more common in the AC <10th percentile group as compared to the AC ≥10th percentile group (p = .04). Placentas from the AC <10th percentile group were smaller (p < .001), with more MVM lesions (p = .02) and chronic villitis (p = .04). By multivariate regression analysis, AC <10th percentile and maternal hypertensive disorders, were found to be independently associated with placental MVM lesions, aOR = 2.43 (95% CI 1.04, 5.88) and aOR = 3.15 (95% CI 1.06, 9.31), respectively.Conclusions: Higher rate of placental maternal malperfusion lesions, chronic villitis, and more neonatal hypoglycemia characterize SGA neonates with AC <10th percentile, pointing to the importance of AC measurement as an indicator for placental insufficiency.

The Placental Basis of Fetal Growth Restriction

Placental dysfunction is a major contributing factor to fetal growth restriction. Placenta-mediated fetal growth restriction occurs through chronic fetal hypoxia owing to poor placental perfusion through a variety of mechanisms. Maternal vascular malperfusion is the most common placental disease contributing to fetal growth restriction; however, the role of rare placental diseases should not be overlooked. Although the features of maternal vascular malperfusion are identifiable on placental pathology, antepartum diagnostic methods are evolving. Placental imaging and uterine artery Doppler, used in conjunction with angiogenic growth factors (specifically placenta growth factor and soluble fms-like tyrosine kinase-1), play an increasingly important role.

Nicotine protects fetus against LPS-induced fetal growth restriction through ameliorating placental inflammation and vascular development in late pregnancy in rats

Our previous work has shown that nicotine suppressed lipopolysaccharide (LPS)-induced placental inflammation by inhibiting cytokine release as well as infiltration of leukocytes into the placenta through the cholinergic anti-inflammatory pathway. Nicotine also increased fetal survival and restored pup weight. In the present study, we aim to further investigate if fetal growth restriction (FGR) occurs with LPS treatment, and evaluate the protective effects of nicotine on fetuses in late gestation of rats. Pregnant Sprague–Dawley rats were divided into control group, nicotine group, LPS group and LPS + nicotine group. Rats were first pretreated with nicotine or vehicle by subcutaneous injection on gestation day (GD)14 and GD15, followed by LPS or vehicle intraperitoneal injection on GD16, and were killed on GD18. Loss of fetuses, number and weights of live fetuses and weights of placentas were recorded. Placentas were collected to evaluate placental pathology and determine inflammatory cytokines and vascular endothelial growth factor (VEGF) levels. We found that LPS treatment increased levels of placental inflammatory cytokines and placental pathological damage, decreased levels of VEGF, reduced number of live fetuses and induced FGR. Pretreatment with nicotine reversed LPS-induced high levels of placental inflammatory cytokines, low levels of placental VEGF and placental pathological damage, then rescued the number and weights of live fetuses. These data demonstrated that activation of the cholinergic anti-inflammatory pathway by nicotine protected fetus against LPS-induced FGR through ameliorating placental inflammation and vascular development in late pregnancy in rats. It may be an alternative therapeutic strategy for inflammation- induced FGR in late pregnancy.