Hypoxic patterns of placental injury: a review

Real-time fetal monitoring using photoacoustic measurement of placental oxygen saturation in a rabbit hypoxia model

INTRODUCTION

Ensuring adequate fetal oxygenation is an essential aim of fetal monitoring. The purpose of this study was to establish a basic technique for real-time measurement of blood oxygen saturation of the placenta by photoacoustic (PA) technique as a new fetal monitoring method.

METHODS

The hypoxia model established in our previous study was applied to 7 pregnant rabbits. Three phases were induced: normal phase, hypoxia phase, and recovery phase. Three methods were simultaneously used for real-time fetal monitoring: fetal heat rate (FHR) monitoring, oxygen saturation (SO2) measurement by near-infrared spectroscopy (SNO2), and placenta SO2 measured by PA technique (SplO2). The maternal hypoxia was assessed by skin SO2 measured by PA technique (SsO2), and arterial blood SO2 by blood gas analysis (SaO2).

RESULTS

The average of SplO2 in normal phase was 52.6 ± 13.9 %. The averages of SNO2, SSO2, and SplO2 in the seven rabbits changed in parallel from the normal phase to hypoxia phase. In the recovery phase, the SplO2 rose in parallel with recovery of SaO2. There was lag in increase of the FHR compared to the change in the other values. In the detailed analysis of PA signals from the labyrinth and decidua, a unique change in oxygen saturation was seen in one case.

DISCUSSION

Results of this study showed that sensitivity of our novel PA technique in detecting tissue hypoxia was similar to near-infrared spectroscopy (NIRS). As an advantage, unlike NIRS, monitoring with PA technique was unaffected by ischemia and surface changes in oxygen saturation because of its higher spatial resolution. We conclude that PA technique provides more accurate information about fetal blood placenta than NIRS. Ultrasound imaging, combined with oxygen saturation monitoring by PA technique, would improve fetal monitoring and fetal diagnosis in the future.

Placental fetal vascular malperfusion in congenital diaphragmatic hernia

The success of in-utero or intrapartum treatment for congenital diaphragmatic hernia (CDH) can be impacted by poor placental function; however, this relationship has not yet been studied. To analyze placental histomorphology in CDH, the frequencies of 24 independent clinical and 48 placental phenotypes were compared. Slides from 103 CDH placentas (group 1) and 133 clinical umbilical cord (UC) compromise/anatomical UC abnormality placentas without CDH (group 2) were subjected to hematoxylin/eosin staining and CD34 immunostaining and then examined. CD34 immunostaining was performed to identify clustered distal villi with endothelial fragmentation of recent fetal vascular malperfusion (FVM). Cesarean delivery and ex utero intrapartum treatment were more common in group 1, but group 2 showed a higher frequency of statistically significant increases in other clinical phenotypes. The frequencies of large vessels and distal villous FVMs (clustered endothelial fragmentation by CD34 immunostaining, stromal vascular karyorrhexis, avascular, or mineralized villi) did not differ between the groups, but low-grade distal villous FVMs were statistically significantly more common in group 1 than in group 2, while high-grade distal villous FVMs were significantly more common in group 2 than group 1. Large vessel and distal villous FVMs were manyfold more common in both the CDH and UC compromise groups than in the general population. However, CDH placentas were more likely to show low-grade distal villous FVMs and less likely to show high-grade distal villous FVMs in UC compromise placentas. FVM of CDH may therefore be caused by a similar pathomechanism as that of UC compromise, resulting in impaired placental fetal blood outflow.

Single Umbilical Artery Umbilical Cord Is Associated With High-Grade Distal Fetal Vascular Malperfusion

PURPOSE AND CONTEXT

Umbilical cord abnormalities with clinical signs of cord compromise are frequently associated with fetal vascular malperfusion (FVM). Single umbilical artery (SUA) has been reported to be associated with high-grade FVM in fetal growth restriction but not in an unselected population; our study aimed to address this issue.

METHODS

Clinical and placental phenotypes of 55 consecutive placentas with SUA (Group 1) were compared with those of 655 placentas with 3-vessel umbilical cord (Group 2) from patients who were in the second half of their pregnancy. The placentas were histologically examined using hematoxylin and eosin (H&E) staining and CD 34 immunostaining.

KEY RESULTS

Several umbilical cord phenotypes and high-grade distal FVM, based on H&E staining and endothelial fragmentation by CD34 were significantly more common in Group 1, whereas decidual clusters of multinucleate trophoblasts were more common in Group 2. Notably, H&E staining or CD34 immunostaining evaluated separately showed that high-grade distal FVM was more common in Group 1 than in Group 2, but the difference was not statistically significant.

CONCLUSIONS

SUA predisposes to remote, advanced, and recent high-grade distal villous FVM, with a pathogenesis partly different from that of stasis-induced FVM, likely related to fetal anomalies associated with SUA.

Placental Histopathologic Findings of a Large Cohort of Patients With SARS-CoV-2 Infection During Pregnancy

Pregnant individuals with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are at a higher risk for adverse pregnancy outcomes. Previous small cohort studies have shown increased frequency of placental lesions associated with maternal vascular malperfusion, fetal vascular malperfusion, and inflammation among patients with SARS-CoV-2, without controlling for cardiometabolic risk factors among many such patients. We aimed to evaluate whether SARS-CoV-2 infection during pregnancy is independently associated with placental abnormalities when controlling for risk factors that could affect placental histopathology. Retrospective cohort study of placentas from singleton pregnancies in Kaiser Permanente Northern California from March to December 2020. Pathologic findings were compared among those with confirmed cases of SARS-CoV-2 during pregnancy and those without. We examined the association between SARS-CoV-2 infection and categorical placental pathologies, controlling for maternal age, gestational age, prepregnancy body mass index, gestational hypertension, preeclampsia/eclampsia, preexisting diabetes, history of thrombosis, and stillbirth. A total of 2,989 singleton gestation placentas were analyzed, 416 (13%) from pregnancies with SARS-CoV-2 infection and 2,573 (86%) from those without infection. Among placentas from pregnancies with SARS-CoV-2, 54.8% had evidence of inflammation, 27.1% maternal malperfusion abnormality, 20.7% massive perivillous fibrin or chronic villitis, 17.3% villous capillary abnormality, and 15.1% fetal malperfusion. After controlling for risks factors and stratifying interval time between SARS-CoV-2 infection and delivery, no association was found between placental abnormalities and SARS-CoV-2 infection during pregnancy. SARS-CoV-2 infection was not associated with an increased risk of placentally mediated adverse outcomes during pregnancy, compared with placentas sent for other indications, in this large diverse cohort.

CD34 immunostain increases the sensitivity of placental examination for distal fetal vascular malperfusion in liveborn infants

INTRODUCTION

Placental fetal vascular malperfusion (FVM) is associated with increased perinatal morbidity and mortality. This retrospective observational analysis was performed to compare the impact of large proximal vessel (global) FVM, established/remote distal villous FVM, and recent (acute) FVM diagnosed by clustered endothelial fragmentation by CD34 immunostaining, on clinical and other placental phenotypes.

METHODS

Clinical and placental phenotypes of 581 consecutive high-risk pregnancies with a live birth divided in five groups based on presence and type of FVM were analyzed. CD34 immunostaining was performed on all cases to refine the diagnosis of FVM. The statistical analysis was by ANOVA and Chi square.

RESULTS

FVM was present in 88% of placentas from pregnancies dominated by congenital anomalies. 43% of those had global FVM (partial, large proximal vessel) without distal villous changes, either acute (endothelial fragmentation) or established (avascular villi). Acute distal villous FVM without avascular villi did not link with significant perinatal morbidity/mortality, likely because of its short duration. Established distal villous FVM with active endothelial fragmentation, labelled as FVM with temporal heterogeneity, is associated with preterm births, preeclampsia, abnormal Dopplers, fetal growth restriction, highest cesarean section rate, and high grade FVM, particularly the latter.

DISCUSSION

Lesions of global FVM are common, featuring relatively low sensitivity for perinatal complications. Caution is indicated in assigning significance to isolated lesions such as fetal vascular ectasia, intramural fibrin deposition and stem vessel obliteration. Established and on-going FVM diagnosed by using CD34 immunostain, is much more significant and portends the most complicated perinatal outcomes.

Shallow Placentation: A Distinct Category of Placental Lesions

OBJECTIVE

Shallow placental implantation (SPI) features placental maldistribution of extravillous trophoblasts and includes excessive amount of extravillous trophoblasts, chorionic microcysts in the membranes and chorionic disc, and decidual clusters of multinucleate trophoblasts. The histological lesions were previously and individually reported in association with various clinical and placental abnormalities. This retrospective statistical analysis of a large placental database from high-risk pregnancy statistically compares placentas with and without a composite group of features of SPI.

STUDY DESIGN

Twenty-four independent abnormal clinical and 44 other than SPI placental phenotypes were compared between 4,930 placentas without (group 1) and 1,283 placentas with one or more histological features of SPI (composite SPI group; group 2). Placentas were received for pathology examination at a discretion of obstetricians. Placental lesion terminology was consistent with the Amsterdam criteria, with addition of other lesions described more recently.

RESULTS

Cases of group 2 featured statistically and significantly (p < 0.001after Bonferroni's correction) more common than group 1 on the following measures: gestational hypertension, preeclampsia, oligohydramnios, polyhydramnios, abnormal Dopplers, induction of labor, cesarean section, perinatal mortality, fetal growth restriction, stay in neonatal intensive care unit (NICU), congenital malformation, deep meconium penetration, intravillous hemorrhage, villous infarction, membrane laminar necrosis, fetal blood erythroblastosis, decidual arteriopathy (hypertrophic and atherosis), chronic hypoxic injury (uterine and postuterine), intervillous thrombus, segmental and global fetal vascular malperfusion, various umbilical cord abnormalities, and basal plate myometrial fibers.

CONCLUSION

SPI placentas were statistically and significantly associated with 48% abnormal independent clinical and 51% independent abnormal placental phenotypes such as acute and chronic hypoxic lesions, fetal vascular malperfusion, umbilical cord abnormalities, and basal plate myometrial fibers among others. Therefore, SPI should be regarded as a category of placental lesions related to maternal vascular malperfusion and the "Great Obstetrical Syndromes."

KEY POINTS

· SPI reflects abnormal distribution of extravillous trophoblasts.. · SPI features abnormal clinical and placental phenotypes.. · SPI portends increased risk of complicated perinatal outcome..

Synoptic Reporting in Clinical Placental Pathology: A Preliminary Investigation Into Report Findings and Interobserver Agreement

INTRODUCTION

Placental pathology is key for investigating adverse pregnancy outcomes, however, lack of standardization in reporting has limited clinical utility. We evaluated a novel placental pathology synoptic report, comparing its robustness to narrative reports, and assessed interobserver agreement.

METHODS

100 singleton placentas were included. Histology slides were examined by 2 senior perinatal pathologists and 2 pathology residents using a synoptic report (32 lesions). Historical narrative reports were compared to synoptic reports. Kappa scores were calculated for interobserver agreement between senior, resident, and senior vs resident pathologists.

RESULTS

Synoptic reporting detected 169 (51.4%) lesion instances initially not included in historical reports. Amongst senior pathologists, 64% of all lesions examined demonstrated fair-to-excellent agreement (Kappa ≥0.41), with only 26% of Kappas ≥0.41 amongst those examined by resident pathologists. Well-characterized lesions (e.g., chorioamnionitis) demonstrated higher agreement, with lower agreement for uncommon lesions and those previously shown to have poor consensus.

DISCUSSION

Synoptic reporting is one proposed method to address issues in placenta pathology reporting. The synoptic report generally identifies more lesions compared to the narrative report, however clinical significance remains unclear. Interobserver agreement is likely related to differential in experience. Further efforts to improve overall standardization of placenta pathology reporting are needed.

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.

Machine learning-based placental clusters and their associations with adverse pregnancy outcomes

BACKGROUND

Placental abnormalities have been described in clinical convenience samples, with predominately adverse outcomes. Few studies have described placental patterns in unselected samples.

OBJECTIVE

We aimed to investigate associations between co-occurring placental features and adverse pregnancy outcomes in a prospective cohort of singletons.

METHODS

Data were from the Safe Passage study (U.S. and South Africa, 2007-2015). Before 24 weeks' gestation, participants were randomly invited to donate placental tissue at delivery for blinded, standardised pathological examination. We used hierarchical clustering to construct statistically derived groups using 60 placental features. We estimated associations between the placental clusters and select adverse pregnancy outcomes, expressed as unadjusted and adjusted risk ratios (RRs) and robust 95% confidence intervals (CI).

RESULTS

We selected a 7-cluster model. After collapsing 2 clusters to form the reference group, we labelled the resulting 6 analytic clusters according to the overarching category of their most predominant feature(s): severe maternal vascular malperfusion (n = 117), fetal vascular malperfusion (n = 222), other vascular malperfusion (n = 516), inflammation 1 (n = 269), inflammation 2 (n = 175), and normal (n = 706). Risks for all outcomes were elevated in the severe maternal vascular malperfusion cluster. For instance, in unadjusted analyses, this cluster had 12 times the risk of stillbirth (RR 12.07, 95% CI 4.20, 34.68) and an almost doubling in the risk of preterm delivery (RR 1.93, 95% CI 1.27, 2.93) compared with the normal cluster. Small infant size was more common among the abnormal clusters, with the highest unadjusted RRs observed in the fetal vascular malperfusion cluster (small for gestational age birth RR 2.99, 95% CI 2.24, 3.98, head circumference <10th percentile RR 2.86, 95% CI 1.60, 5.12). Upon adjustment for known risk factors, most RRs attenuated but remained >1.

CONCLUSION

Our study adds to the growing body of epidemiologic research, finding adverse pregnancy outcomes may occur through etiologic mechanisms involving co-occurring placental abnormalities.

Placenta-Derived Extracellular Vesicles in Pregnancy Complications and Prospects on a Liquid Biopsy for Hemoglobin Bart's Disease

Extracellular vesicles (EVs) are nano-scaled vesicles released from all cell types into extracellular fluids and specifically contain signature molecules of the original cells and tissues, including the placenta. Placenta-derived EVs can be detected in maternal circulation at as early as six weeks of gestation, and their release can be triggered by the oxygen level and glucose concentration. Placental-associated complications such as preeclampsia, fetal growth restriction, and gestational diabetes have alterations in placenta-derived EVs in maternal plasma, and this can be used as a liquid biopsy for the diagnosis, prediction, and monitoring of such pregnancy complications. Alpha-thalassemia major ("homozygous alpha-thalassemia-1") or hemoglobin Bart's disease is the most severe form of thalassemia disease, and this condition is lethal for the fetus. Women with Bart's hydrops fetalis demonstrate signs of placental hypoxia and placentomegaly, thereby placenta-derived EVs provide an opportunity for a non-invasive liquid biopsy of this lethal condition. In this article, we introduced clinical features and current diagnostic markers of Bart's hydrops fetalis, extensively summarize the characteristics and biology of placenta-derived EVs, and discuss the challenges and opportunities of placenta-derived EVs as part of diagnostic tests for placental complications focusing on Bart's hydrop fetalis.

Cesarean section per se is not a risk factor for non-anatomical placenta creta

OBJECTIVE

To investigate whether mild forms of placenta creta (MPC) are more common in placentas delivered by cesarean section for non-anatomical indications than in placentas from vaginal deliveries.

METHODS

This is a retrospective clinical study in which MPC was diagnosed histologically by the presence of myometrial fibers in the decidua basalis or parietalis or in direct contact with the Rohr fibrinoid or chorionic villi. After excluding 111 cases at high risk for anatomical PC, placentas from 830 consecutive cesarean deliveries (group 1) were retrospectively statistically compared with 907 placentas from vaginal deliveries (group 2).

RESULTS

Statistically significant differences were found in six independent clinical and seven placental phenotypes. More frequently, pre-eclampsia, abnormal fetal heart rate tracing and umbilical artery Dopplers, hypercoiled umbilical cord, diffuse postuterine pattern of chronic hypoxic placental injury, and clusters of avascular or mineralized chorionic villi were found in group 1, while preterm delivery, induction of labor, and histological patterns related to stillbirth were observed in group 2.

CONCLUSION

MPC diagnosed in placentas from cesarean sections performed for non-anatomical indications is not statistically significantly more common than in those after vaginal delivery. Therefore, MPC may feature similar diagnostic correlations and portend a similar prognosis for future pregnancies.

Pregnancy complications after allogeneic hematopoietic stem cells transplantation: Focus on the placenta

INTRODUCTION

hematopoietic stem cells transplantation (HSCT) is a treatment option for malignant and non-malignant haematological diseases. Because of the improved survival rates and the more widespread use of reproductive technologies in the last two decades, the number of patients who conceive is increasing while the pathogenesis of some obstetrical complications observed is not yet fully clarified.

METHODS

we present complete data about two pregnancies in women who had previously undergone HSTC, with conditioning regimen including total body irradiation. One pregnancy is spontaneous and one after oocytes donation.

RESULTS

In both pregnancies we observed relevant intrauterine growth retardation, attributable to a deficit in implantation and placentation. Ultrasound and histological data point to a defective placenta development, possibly sustained by uterine vessel damage caused by irradiation. A deeper understanding of factors influencing placentation post total body irradiation and HSCT, including the possible role of donor's sex and graft versus host disease, is pivotal to improve pregnancy outcomes in this specific population.

Is there an association between isolated sonographic abdominal circumference below the 10th percentile and placental vascular lesions?

OBJECTIVE

To study the association between prenatal diagnosis of isolated abdominal circumference (AC) below the 10th percentile (AC <10th) in appropriate for gestational age (AGA) neonates and placental vascular lesions.

METHODS

A prospective study was conducted of healthy women who underwent sonographic fetal biometric measurements, up to 7 days before delivery, and delivered AGA neonates. The study cohort was divided into those with and without prenatal isolated AC <10th. Placental histopathology lesions were classified into maternal and fetal vascular malperfusion (MVM, FVM) lesions.

RESULTS

Compared to the AC over 10th percentile group (n = 85), the AC <10th group (n = 85) was characterized by lower maternal body mass index, higher rate of smokers, and increased rate of induced labor (P = 0.029, P = 0.029, P = 0.001, respectively). There were no between-group differences regarding maternal age, gestational age, and neonatal outcome. Mean placental weight was lower in the isolated AC <10th (P < 0.001). The rate of MVM or FVM lesions did not differ between the groups. By multivariate logistic regression analysis, isolated AC <10th was not found to be associated with increased risk for placental vascular lesions.

CONCLUSION

Isolated AC <10th is associated with increased rate of induction of labor; however, it is not associated with increased placental vascular lesions.

Patterns of placental injury in various types of fetal congenital heart disease

OBJECTIVES

Fetal blood circulation may be modified in congenital heart disease (CHD). This retrospective analysis was performed to study whether the type of CHD is associated with specific placental pathology.

METHODS

3 types of CHD based on presumed proportion of placental and systemic blood distribution in fetal circulation were analyzed: Group 1: 89 cases with low placental blood content (hypoplastic left heart syndrome, transposition of great arteries, coarctation of aorta), Group 2: 71 placentas with intermediate placental and systemic blood content due to increased intracardiac blood mixing (tetralogy of Fallot, truncus arteriosus, double inlet/outlet ventricle), and Group 3: 24 placentas with high placental blood content (tricuspid or pulmonary atresia, Ebstein anomaly). Frequencies of 27 independent clinical and 47 placental phenotypes of 184 placentas in those three groups were statistically compared.

RESULTS

The most advanced gestational age at delivery, and large vessel (global) fetal vascular malperfusion (FVM) were most common in Group 1, while macerated stillbirths, neonatal mortality, abnormal amniotic fluid volume (oligohydramnios or polyhydramnios), other congenital anomalies, distal villous lesions of FVM, placental edema and amnion nodosum were most common in Groups 2 and 3, although the frequencies of placental lesions were statistically not significant.

CONCLUSIONS

Left heart obstructive lesions potentially associated with brain maldevelopment show increase in lesions of global FVM (in aggregate and individually fetal vascular ectasia, stem vessel obliteration and intramural fibrin deposition) as may be seen in umbilical cord compromise. CHD with increased intracardiac blood mixing or with right heart defects is associated with average preterm gestational age at delivery and placental lesions of distal villous FVM, villous edema and amnion nodosum.

Maternal Physiological Variations Induced by Chronic Gestational Hypoxia: 1H NMR-Based Metabolomics Study

Metabolomics have been widely used in pregnancy-related diseases. However, physiological variations induced by chronic hypoxia during pregnancy are not well characterized. We aimed to investigate physiological variations induced by chronic hypoxia during pregnancy. A Sprague-Dawley (SD) pregnant rat model of chronic hypoxia was established. Plasma and urine metabolite profiles at different stages of the pregnancy were detected by ¹H NMR (nuclear magnetic resonance). Multivariate statistical analysis was used to analyze changes in plasma and urine metabolic trajectories at different time-points. We identified hypoxia-induced changes in the levels of 30 metabolites in plasma and 29 metabolites in urine during different stages of pregnancy; the prominently affected metabolites included acetic acid, acetone, choline, citric acid, glutamine, isoleucine, lysine, and serine. Most significant hypoxia-induced changes in plasma and urine sample metabolites were observed on the 11th day of gestation. In summary, chronic hypoxia has a significant effect on pregnant rats, and may cause metabolic disorders involving glucose, lipids, amino acids, and tricarboxylic acid cycle. Metabolomics study of the effect of hypoxia during pregnancy may provide insights into the pathogenesis of obstetric disorders.

Placental pathology of resuscitated apparent stillbirth

Resuscitated apparent stillbirth (RAS) is defined as an infant with APGAR scores of 0 at 1 minute of life who receives successful resuscitation. Assessment of placental pathology is considered standard of care in such infants, but the clinical significance of these placental findings as they relate to clinical outcomes has yet to be described within the literature. We report the findings of a retrospective study of placental pathology as defined by the Amsterdam and Dublin criteria of RAS infants born in South Australia over an 8-year period. The aim of this study was to assess whether placental pathology was able to predict RAS clinical outcomes of death, survival with adverse neurological outcomes, and survival with normal neurological outcomes. The RAS cohort within our study is small, reflecting the low incidence of RAS. Of the 25 RAS subjects 16 survived, five with abnormal neurological outcomes and 11 with normal neurological outcomes. No statistically significant difference was seen between the clinical outcome groups in the incidence of specific macroscopic and microscopic placental findings. No sentinel lesion was seen in any one clinical outcome group. Relevant placental pathology was found in all but one subject validating the role of placental pathology in determination of the aetiology of RAS. The most common finding was maternal vascular malperfusion. Placental pathology in RAS infants remains relevant but is unable to contribute to the matrix of predictive information available to the clinician and family.

The role of the placenta in spontaneous preterm labor and delivery with intact membranes

OBJECTIVES

To determine whether placental vascular pathology and impaired placental exchange due to maturational defects are involved in the etiology of spontaneous preterm labor and delivery in cases without histologic acute chorioamnionitis.

METHODS

This was a retrospective, observational study. Cases included pregnancies that resulted in spontaneous preterm labor and delivery (<37 weeks), whereas uncomplicated pregnancies that delivered fetuses at term (≥37-42 weeks of gestation) were selected as controls. Placental histological diagnoses were classified into three groups: lesions of maternal vascular malperfusion, lesions of fetal vascular malperfusion, and placental microvasculopathy, and the frequency of each type of lesion in cases and controls was compared. Moreover, we specifically searched for villous maturational abnormalities in cases and controls. Doppler velocimetry of the umbilical and uterine arteries were performed in a subset of patients.

RESULTS

There were 184 cases and 2471 controls, of which 95 and 1178 had Doppler studies, respectively. The frequency of lesions of maternal vascular malperfusion was greater in the placentas of patients with preterm labor than in the control group [14.1% (26/184) vs. 8.8% (217/2471) (p=0.023)]. Disorders of villous maturation were more frequent in the group with preterm labor than in the control group: 41.1% (39/95) [delayed villous maturation in 31.6% (30/95) vs. 2.5% (13/519) in controls and accelerated villous maturation in 9.5% (9/95) vs. none in controls].

CONCLUSIONS

Maturational defects of placental villi were associated with approximately 41% of cases of unexplained spontaneous preterm labor and delivery without acute inflammatory lesions of the placenta and with delivery of appropriate-for-gestational-age fetuses.

Hypoxia and inflammation conditions differentially affect the expression of tissue transglutaminase spliced variants and functional properties of extravillous trophoblast cells

PROBLEM

Persistent hypoxia and inflammation beyond early pregnancy are involved in a bad outcome because of defective trophoblast invasiveness. Tissue transglutaminase (TG2) coregulates several cell functions. An aberrant expression and/or transamidation activity could contribute to placental dysfunction.

METHOD OF STUDY

The first-trimester trophoblast cell line (Swan-71) was used to study TG2 expression and cell functions in the absence or presence of inflammatory cytokines (TNF-α, IL-1β) or chemical hypoxia (CoCl₂ ). We analyzed The concentration of cytokines in the supernatant by ELISA; Cell migration by scratch assay; NF-κB activation by detection of nuclear p65 by immunofluorescence or flow cytometry using a Swan-71 NF-κB-hrGFP reporter cell line. Tissue transglutaminase expression was analyzed by immunoblot and confocal microscopy. Expression of spliced mRNA variants of tissue transglutaminase was analyzed by RT-PCR. Transamidation activity was assessed by flow cytometry using 5-(biotinamido)-pentylamine substrate.

RESULTS

Chemical hypoxia and TGase inhibition, but not inflammatory stimuli, decreased Swan-71 migration. IL-6 production was also decreased by chemical hypoxia, but increased by inflammation. Intracellular TGase activity was increased by all stimuli, but NF-κB activation was observed only in the presence of proinflammatory cytokines. TG2 expression was decreased by CoCl₂ and TNF-α. Translocation of TG2 and p65 to nuclei was observed only with TNF-α, without colocalization. Differential relative expression of spliced variants of mRNA was observed between CoCl₂ and inflammatory stimuli.

CONCLUSION

The observed decrease in total TG2 expression and relative increase in short variants under hypoxia conditions could contribute to impaired trophoblast invasion and impact on pregnancy outcome.

Laminar Necrosis and Hypoxic Damage of the Placenta: A Case-Control Study

The aim of this study is to verify the role of laminar necrosis (LN) in the diagnosis of hypoxic damage of the placenta. This is a retrospective case-control study in which 50 cases with laminar necrosis were compared with 100 gestational age-matched controls without laminar necrosis in a 1:2 ratio. The parameters analyzed were: the presence of other placental lesions, obstetric characteristics and neonatal outcome. For each of the 50 cases, the area affected by the lesion was detected, and the lesions were classified into three groups based on the morphology and time of onset of the lesion in order to understand whether these characteristics of the lesion had a clinical-pathology. The results showed that including the search for LN among placental lesions generally examined is useful to guide the pathologist in the diagnosis of placental dysfunction of hypoxic origin.

Erythroblasts in the Vessels of the Placenta – An Independent Factor of Chronic Hypoxic Damage to the Fetus

The aim is a comparative histological study of the relative number of fetal erythroblasts in the vessels of the placentas from a full term pregnancy with a low and high risk of fetal hypoxic damage. Material and methods. Based on data on the course of pregnancy, the state of health of the mother and the fetus/newborn, as well as histological examination of the placenta, 388 archived placenta tissue samples were selected in 2 groups: a high risk group for chronic hypoxic damage to the fetus and a group without clinical and laboratory signs of fetal/newborn hypoxia. The relationship between the number of erythroblasts in the vessels of the placenta and chronic hypoxic damage to the fetus was analyzed. Results: The high risk of chronic hypoxic fetal damage is higher for placentas with ≥8 fetal erythroblasts in chorionic villi vessels (OR=3.175; 95% CI =1.921-5.248, p<0.001), with maternal vascular malperfusion (OR=2.798; 95% CI = 1.506-5.164, p=0.001) and combined (cross) placental lesions (OR=2.245; 95%CI=1.246-4.046, p =0.007) with damage of ≥30% of placental tissue. Conclusion: 8 or more fetal erythroblasts in the lumen of the vessels of the placenta is an additional independent factor in chronic hypoxic damage to the fetus. These results are of practical importance for identifying a group of newborns with a high risk of chronic hypoxic damage in the perinatal period and stratification of the risk group in the postnatal period in order to reduce infant morbidity and mortality.  

Cardiovascular determinants of impaired placental function in women with cardiac dysfunction

Female heart disease has for a long time been an underrecognized problem in the field of cardiology. With an ever-growing number of these patients getting pregnant, cardiac dysfunction during pregnancy is an increasingly large medical problem. Previous work has shown that maternal heart disease may have an adverse effect on pregnancy outcome in both mother and child. The placenta forms the connection and it is postulated that cardiac dysfunction negatively affects the placenta, and consequently, neonatal outcome. Given the paucity of data in this field, more research on the influence of cardiac (mal)function on placental (mal)function is needed. The present review describes placental function in women with various types of cardiac dysfunction, thereby aiming to provide more insight into possible underlying mechanisms of placental malfunction. Organ dysfunction in patients with heart failure is for an important part based on reduced perfusion and venous congestion. This has been shown in other organs such as kidneys, liver and brain. In pregnant women with cardiac dysfunction, placental dysfunction may follow similar patterns. Moreover, other factors, such as pre-existing hypertension and chronic hypoxia may lead to further impairment of placental function, through abnormal vascular remodeling of the uterine spiral arteries. The pathophysiology of placental dysfunction in pregnant women with cardiac dysfunction may thus be multifactorial. It is therefore important to monitor closely cardiac and placental function in such high-risk pregnancies. Gaining a better understanding of the underlying pathophysiological mechanisms may have important clinical implications in terms of pregnancy counseling, monitoring and outcome.

Association of Maternal Serum Ischemia Modified Albumin (IMA) with Placental Histopathological Changes and Fetomaternal Outcome: A Prospective Case Control Study in Normotensive and Pre-eclamptic Women

Introduction

Ischemia and oxidative stress leads to generation of hydroxyl free radicals and modification of 'N-terminus' of human serum albumin. This modified albumin molecule, known as Ischemia Modified Albumin (IMA), is elevated in early stages of ischemia. It has recently been approved by US Food and Drug Administration (US FDA) for its clinical use, as early marker of myocardial ischemia in cardiology. IMA is a novel marker of ischemia and is elevated in other clinical conditions associated with ischemia like pulmonary embolism, uncontrolled type II diabetes mellitus, acute decompensated heart failure, preeclampsia, recurrent pregnancy losses and IUGR. Role of IMA in birth asphyxia in perinatology is of current interest and needs further research.

Methodology

A prospective case control study was conducted in a tertiary center in North India for one year. Total 80 pregnant women between 34 and 40 weeks were recruited and allocated in two groups. Case group comprised of 40 pre-eclamptic pregnant women and control group comprised of 40 normotensive pregnant women. Comparison and association of maternal serum IMA levels with fetomaternal outcome and number and types of placental histopathological changes was done in two groups.

Results

In preeclampsia group mean serum IMA (115.23 ± 49.51) was significantly higher as compared to the normotensive group (79.21 ± 14.35). The optimum cut off value of IMA to detect a case was 94.5 IU/ml (sensitivity 65%, specificity 87.5%, PPV 83.9%, NPV 71.4% and diagnostic accuracy of 76.3). Pre-eclamptic women, had significantly higher incidence of PTVD, lower fetal birth weight and placental histopathological changes as compared to normotensive group. 83.8% of the women with raised IMA levels were pre-eclamptic. Raised IMA levels were significantly associated with higher incidence of PTVD, birth weight ≤ 2 kg and hypoxic histopathological lesions of chorangiosis, intervillous fibrin and hyalinization.

Conclusion

Determination of maternal serum IMA levels early in pregnancy can predict preeclampsia and avoid future severe preeclampsia related complications. It might be useful to optimize both maternal and fetal/neonatal outcomes.

Syncytiotrophoblast stress in preeclampsia: the convergence point for multiple pathways

Preeclampsia evolves in 2 stages: a placental problem that generates signals to the mother to cause a range of responses that comprise the second stage (preeclampsia syndrome). The first stage of early-onset preeclampsia is poor placentation, which we here call malplacentation. The spiral arteries are incompletely remodeled, leading to later placental malperfusion, relatively early in the second half of pregnancy. The long duration of the first stage (several months) is unsurprisingly associated with fetal growth restriction. The first stage of late-onset preeclampsia, approximately 80% of total cases, is shorter (several weeks) and part of a process that is common to all pregnancies. Placental function declines as it outgrows uterine capacity, with increasing chorionic villous packing, compression of the intervillous space, and fetal hypoxia, and causes late-onset clinical presentations such as "unexplained" stillbirths, late-onset fetal growth restriction, or preeclampsia. The second stages of early- and late-onset preeclampsia share syncytiotrophoblast stress as the most relevant feature that causes the maternal syndrome. Syncytiotrophoblast stress signals in the maternal circulation are probably the most specific biomarkers for preeclampsia. In addition, soluble fms-like tyrosine kinase-1 (mainly produced by syncytiotrophoblast) is the best-known biomarker and is routinely used in clinical practice in many locations. How the stress signals change over time in normal pregnancies indicates that syncytiotrophoblast stress begins on average at 30 to 32 weeks' gestation and progresses to term. At term, syncytiotrophoblast shows increasing markers of stress, including apoptosis, pyroptosis, autophagy, syncytial knots, and necrosis. We label this phenotype the "twilight placenta" and argue that it accounts for the clinical problems of postmature pregnancies. Senescence as a stress response differs in multinuclear syncytiotrophoblast from that of mononuclear cells. Syncytiotrophoblast irreversibly acquires part of the senescence phenotype (cell cycle arrest) when it is formed by cell fusion. The 2 pathways converge on the common pathologic endpoint, syncytiotrophoblast stress, and contribute to preeclampsia subtypes. We highlight that the well-known heterogeneity of the preeclampsia syndrome arises from different pathways to this common endpoint, influenced by maternal genetics, epigenetics, lifestyle, and environmental factors with different fetal and maternal responses to the ensuing insults. This complexity mandates a reassessment of our approach to predicting and preventing preeclampsia, and we summarize research priorities to maximize what we can learn about these important issues.

MiR-212-3p promotes proliferation and migration of trophoblast in fetal growth restriction by targeting placental growth factor

The purpose of this study was to evaluate the function and possible mechanism of miR-212-3p in fetal growth restriction (FGR) and to demonstrate the relationship between miR-212-3p and placental growth factor (PGF). First, we used qRT-PCR to detect the expression of miR-212-3p and PGF in placental tissues of normal delivery (HC group) and FGR, as well as in human trophoblast cell HTR-8/Svneo. The results revealed that miR-212-3p expression was significantly upregulated and PGF was significantly downregulated in placental tissue in the FGR group compared with the HC group. In addition, interference with miR-212-3p expression increased the proliferation, invasion, and migration of HTR-8/SVneo cells and decreased apoptosis of cells. Meanwhile, Western blot results showed that miR-212-3p expression downregulation promoted the phosphorylated protein expression of Phosphoinositide 3-kinase (PI3K) and protein kinase B (AKT), which in turn activated the PI3K/AKT signaling pathway. And the results of dual luciferase reporter further showed that miR-212-3p could target PGF, and the expression of both was negatively correlated in FGR group tissues. In addition, downregulation of miR-212-3p expression reversed the inhibitory effect of PGF downregulation on HTR-8/SVneo cells. In conclusion, miR-212-3p can target and inhibit the PGF expression and regulate the PI3K/AKT signaling pathway to regulate trophoblast cell invasion, migration, proliferation and cell apoptosis. This provides a potential biomarker for the development of FGR.

Placental Vascular Abnormalities in Association With Prenatal and Long-Term Health Characteristics Among HIV-Exposed Uninfected Adolescents and Young Adults

BACKGROUND

HIV-exposed uninfected (HEU) individuals are predisposed to adverse health outcomes, which in part may stem from the influence of an altered intrauterine milieu on fetal programming. The placenta serves as a readout for the effects of the maternal environment on the developing fetus and may itself contribute to the pathogenesis of disease.

SETTING

US academic health system.

METHODS

We leveraged a previously established registry-based cohort of HEU adolescents and young adults to identify 26 subjects for whom placental histopathology was available. We further obtained placental tissue from 29 HIV-unexposed pregnancies for comparison. We examined differences in placental histopathology between the groups and related villous vascularity in the HEU group to prenatal maternal characteristics and long-term health outcomes.

RESULTS

Placentas from HEU pregnancies demonstrated a higher blood vessel count per villus as compared with controls (5.9 ± 1.0 vs. 5.4 ± 0.8; P = 0.05), which was independent of maternal prenatal age, race, body mass index, smoking status, hemoglobin, and gestational age. Furthermore, within the HEU group, lower CD4+ T-cell count during pregnancy was associated with greater placental vascularity (r = -0.44; P = 0.03). No significant relationships were observed between placental blood vessel count per villus and body mass index z-score or reactive airway disease among HEU individuals later in life.

CONCLUSIONS

Placentas from HEU pregnancies demonstrated increased villous vascularity compared with HIV-unexposed controls in proportion to the severity of maternal immune dysfunction. Further studies are needed to examine intrauterine exposure to hypoxia as a potential mechanism of fetal programming in HIV.

Fetal oxygen supply can be improved by an effective cross-talk between fetal erythrocytes and vascular endothelium

In twin/multiple pregnancy, siblings experience an adverse intrauterine environment which forms the major etiological factor leading to pathological conditions. The status of the developing fetus is highly determined by the nitric oxide (NO) level, that facilitates vasodilation which in turn modulates the oxygen and nutrition supply. As the umbilical cord (UC) lacks innervation, activation of the endothelial nitric oxide synthase (NOS3) is fundamental to maintain adequate NO production. Recent ground breaking fact showed that under stress conditions, circulating red blood cells (RBCs) can actively produces NO as a "rescue mechanism". Therefore, this study majorly focused on the molecular mechanisms that affected the redox environment by altering NOS3 activation - both in the UC arteries and vein endothelium and RBCs - that have impacts on developmental parameters, like birth weight. In connection to that, we pursued the communication efficiency between the vessels' endothelium and the circulating RBCs in demand of bioavailable NO. Our results indicated that twinning itself at stage 33-35 weeks, does not reduce the NOS3 level and its phosphorylation status in the cord vessels. However, RBC-NOS3 activation is highly upregulated during this period - providing additional evidence for the active regulatory role of fetal RBCs in the rate of blood flow - and this functional activity highly correlates with the birth weight of the fetuses. Detailed analysis on NOS3 signalling at different time points of gestation could establish a benchmark in understanding of the pathophysiological mechanisms involved in the process of developing neonatal vascular diseases.

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.

Disorders of placental villous maturation are present in one-third of cases with spontaneous preterm labor

OBJECTIVES

Spontaneous preterm labor is an obstetrical syndrome accounting for approximately 65-70% of preterm births, the latter being the most frequent cause of neonatal death and the second most frequent cause of death in children less than five years of age worldwide. The purpose of this study was to determine and compare to uncomplicated pregnancies (1) the frequency of placental disorders of villous maturation in spontaneous preterm labor; (2) the frequency of other placental morphologic characteristics associated with the preterm labor syndrome; and (3) the distribution of these lesions according to gestational age at delivery and their severity.

METHODS

A case-control study of singleton pregnant women was conducted that included (1) uncomplicated pregnancies (controls, n=944) and (2) pregnancies with spontaneous preterm labor (cases, n=438). All placentas underwent histopathologic examination. Patients with chronic maternal diseases (e.g., chronic hypertension, diabetes mellitus, renal disease, thyroid disease, asthma, autoimmune disease, and coagulopathies), fetal malformations, chromosomal abnormalities, multifetal gestation, preeclampsia, eclampsia, preterm prelabor rupture of the fetal membranes, gestational hypertension, gestational diabetes mellitus, and HELLP (hemolysis, elevated liver enzymes and low platelet count) syndrome were excluded from the study.

RESULTS

Compared to the controls, the most prevalent placental lesions among the cases were the disorders of villous maturation (31.8% [106/333] including delayed villous maturation 18.6% [62/333] vs. 1.4% [6/442], q<0.0001, prevalence ratio 13.7; and accelerated villous maturation 13.2% [44/333] vs. 0% [0/442], q<0.001). Other lesions in decreasing order of prevalence included hypercapillarized villi (15.6% [68/435] vs. 3.5% [33/938], q<0.001, prevalence ratio 4.4); nucleated red blood cells (1.1% [5/437] vs. 0% [0/938], q<0.01); chronic inflammatory lesions (47.9% [210/438] vs. 29.9% [282/944], q<0.0001, prevalence ratio 1.6); fetal inflammatory response (30.1% [132/438] vs. 23.2% [219/944], q<0.05, prevalence ratio 1.3); maternal inflammatory response (45.5% [195/438] vs. 36.1% [341/944], q<0.01, prevalence ratio 1.2); and maternal vascular malperfusion (44.5% [195/438] vs. 35.7% [337/944], q<0.01, prevalence ratio 1.2). Accelerated villous maturation did not show gestational age-dependent association with any other placental lesion while delayed villous maturation showed a gestational age-dependent association with acute placental inflammation (q-value=0.005).

CONCLUSIONS

Disorders of villous maturation are present in nearly one-third of the cases of spontaneous preterm labor.

CD34 immunostain increases sensitivity of the diagnosis of fetal vascular malperfusion in placentas from ex-utero intrapartum treatment

OBJECTIVES

EXIT (ex-utero intrapartum treatment) procedure is a fetal survival-increasing modification of cesarean section. Previously we found an increase incidence of fetal vascular malperfusion (FVM) in placentas from EXIT procedures which indicates the underlying stasis of fetal blood flow in such cases. This retrospective analysis analyzes the impact of the recently introduced CD34 immunostain for the FVM diagnosis in placentas from EXIT procedures.

METHODS

A total of 105 placentas from EXIT procedures (48 to airway, 43 to ECMO and 14 to resection) were studied. In 73 older cases, the placental histological diagnosis of segmental FVM was made on H&E stained placental sections only (segmental villous avascularity) (Group 1), while in 32 most recent cases, the CD34 component of a double E-cadherin/CD34 immunostain slides was also routinely used to detect the early FVM (endothelial fragmentation, villous hypovascularity) (Group 2). Twenty-three clinical and 47 independent placental phenotypes were compared by χ² or ANOVA, where appropriate.

RESULTS

There was no statistical significance between the groups in rates of segmental villous avascularity (29 vs. 34%), but performing CD34 immunostain resulted in adding and/or upgrading 12 more cases of segmental FVM in Group 2, thus increasing the sensitivity of placental examination for FVM by 37%. There were no other statistically significantly differences in clinical (except for congenital diaphragmatic hernias statistically significantly more common in Group 2, 34 vs. 56%, p=0.03) and placental phenotypes, proving the otherwise comparability of the groups.

CONCLUSIONS

The use of CD34 immunostain increases the sensitivity of placental examination for FVM by 1/3, which may improve the neonatal management by revealing the increased likelihood of the potentially life-threatening neonatal complications.

An Immunological Perspective: What Happened to Pregnant Women After Recovering From COVID-19?

The coronavirus disease 2019 (COVID-19) pandemic has been raging around the world since January 2020. Pregnancy places the women in a unique immune scenario which may allow severe COVID-19 disease. In this regard, the potential unknown effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on mothers and fetuses have attracted considerable attention. There is no clear consistent evidence of the changes in the immune status of pregnant women after recovery from COVID-19. In this study, we use multiparameter flow cytometry and Luminex assay to determine the immune cell subsets and cytokines, respectively, in the peripheral blood and umbilical cord blood from pregnant women recovering from COVID-19 about 3 months (n=5). Our results showed decreased percentages of Tc2, Tfh17, memory B cells, virus-specific NK cells, and increased percentages of naive B cells in the peripheral blood. Serum levels of IL-1ra and MCP-1 showed a decreased tendency in late recovery stage (LRS) patients. Meanwhile, there was no significant difference in immune cell subsets in the umbilical cord blood. The placentas from LRS patients showed increased CD68+ macrophages infiltration and mild hypoxic features. The inflammatory damage of the placenta may be related to the antiviral response. Since the receptors, ACE2 and TMPRSS2, utilized by SARS-CoV-2 are not co-expressed in the placenta, so it is extremely rare for SARS-CoV-2 to cause infection through this route and the impact on the fetus is negligible.

Association of placental chorangiosis with pregnancy complication and prenatal outcome: a case-control study

Background

Chorangiosis is a vascular change involving the terminal chorionic villi in the placenta. It results from longstanding, low-grade hypoxia in the placental tissue, and is associated with such conditions as intrauterine growth restriction (IUGR), diabetes, and gestational hypertension in pregnancy. Chorangiosis rarely occurs in normal pregnancies. However, its prevalence is 5–7% of all placentas from infants admitted to newborn intensive care units. The present study was aimed at determining the association of chorangiosis with pregnancy complications and perinatal outcomes.

Methods

In this case-control study, 308 chorangiosis cases were compared with 308 controls (with other diagnoses in pathology) in terms of maternal, placental, prenatal, and neonatal characteristics derived from the medical records of participants retrospectively. R and SPSS version 22 software tools were used, and the statistical significance level was considered 0.05 for all the tests.

Results

Preeclampsia, diabetes mellitus, maternal hemoglobin, maternal hematocrit, C/S, oligohydramnios, fetal anomaly, dead neonates, NICU admissions were significantly higher in the chorangiosis group OR = 1.6, 3.98, 1.68, 1.92, 2.1, 4.47, 4.22, 2.9, 2.46, respectively (p-value< 0.05 for all). Amniotic fluid index, birth weight, cord PH amount, 1st, and 5th Apgar score was lower in the chorangiosis group OR = 0.31, 1, 0.097, 0.83, 0.85, respectively (p-value< 0.05 for all). Moreover, fundal placenta, retro placental hemorrhage, perivillous fibrin deposition, calcification, and acute chorioamnionitis were higher in the chorangiosis group OR = 2.1, 11.8, 19.96, 4.05, and 6.38 respectively, (p-value< 0.05). There was a high agreement between the two pathologists, and the power of the study was estimated at 99%.

Conclusion

Although chorangiosis is an uncommon condition, it is associated with a higher incidence of perinatal and neonatal morbidity and mortality. Therefore, it should be considered an important clinical sign of adverse pregnancy outcomes and should be reported in the pathology evaluation.

CD15 immunostaining improves placental diagnosis of fetal hypoxia

INTRODUCTION

Fetal hypoxic events with unclear predictive value are a common indication for placenta examination. We evaluated whether the use of CD15 immunostaining can improve the assessment of severity and duration of fetal hypoxia.

METHODS

We compared placentas (37-42 gestational weeks) from stillborns/newborns with birth asphyxia (BA) and non-hypoxic newborns. Placental findings were studied in following groups: (1) acute BA (n = 11) due to placental abruption, (2) non-acute BA (n = 121) due to non-acute conditions, (3) non-BA (n = 46) in pregnancies with preeclampsia and gestational diabetes, and (4) controls (n = 30).

RESULTS

A high expression of CD15 in feto-placental resistance vessels (FRVs) was present in non-acute BA (95.9%), but absent in acute BA, non-BA and controls (p < 0.0001). Furthermore, we found no causal relationship of high expression of CD15 in FRVs to coexisting placental conditions, including severity and mechanisms/patterns of placental injury, fetal erythroblastosis, and maternal conditions. According to a multivariate analysis, only a high expression of CD15 in FRVs was independently associated with severe non-acute fetal hypoxia ([OR] = 15.52; 95% [CI] = 5.92-40.67).

DISCUSSION

We have defined a characteristic pattern of CD15 expression in FRVs that allows to interpret various clinical/placental conditions with respect to fetal hypoxia, with an improved predictability compared to conventional analyses. This approach represents a novel diagnostic strategy for placenta examination, which could indirectly assess severity and duration of intrauterine hypoxia in a heterogeneous population of newborns.

Adverse Birth Outcomes Due to Exposure to Household Air Pollution from Unclean Cooking Fuel among Women of Reproductive Age in Nigeria

Exposure to household air pollution (HAP) from cooking with unclean fuels and indoor smoking has become a significant contributor to global mortality and morbidity, especially in low- and middle-income countries such as Nigeria. Growing evidence suggests that exposure to HAP disproportionately affects mothers and children and can increase risks of adverse birth outcomes. We aimed to quantify the association between HAP and adverse birth outcomes of stillbirth, preterm births, and low birth weight while controlling for geographic variability. This study is based on a cross-sectional survey of 127,545 birth records from 41,821 individual women collected as part of the 2018 Nigeria Demographic and Health Survey (NDHS) covering 2013-2018. We developed Bayesian structured additive regression models based on Bayesian splines for adverse birth outcomes. Our model includes the mother's level and household characteristics while correcting for spatial effects and multiple births per mother. Model parameters and inferences were based on a fully Bayesian approach via Markov Chain Monte Carlo (MCMC) simulations. We observe that unclean fuel is the primary source of cooking for 89.3% of the 41,821 surveyed women in the 2018 NDHS. Of all pregnancies, 14.9% resulted in at least one adverse birth outcome; 14.3% resulted in stillbirth, 7.3% resulted in an underweight birth, and 1% resulted in premature birth. We found that the risk of stillbirth is significantly higher for mothers using unclean cooking fuel. However, exposure to unclean fuel was not significantly associated with low birth weight and preterm birth. Mothers who attained at least primary education had reduced risk of stillbirth, while the risk of stillbirth increased with the increasing age of the mother. Mothers living in the Northern states had a significantly higher risk of adverse births outcomes in 2018. Our results show that decreasing national levels of adverse birth outcomes depends on working toward addressing the disparities between states.

Placental expression of angiogenesis-related genes and their receptors in IUGR pregnancies: correlation with fetoplacental and maternal parameters

Objectives: Aberrations in placental vascular development compromising fetal supply of oxygen and essential nutrients can be a significant contributor to intrauterine growth restriction (IUGR). The development of placental vascular tree is under the influence of two families of growth factors, namely the vascular endothelial growth factor (VEGF) family and angiopoietin/TEK family. In this study, we have examined the expression of angiogenesis-related growth factors, mainly VEGF family and angiopoietin-TEK (endothelial-specific receptor tyrosine kinase) family genes in placentae from IUGR pregnancies uncomplicated by preeclampsia (PE) compared to normal pregnancies.Methods: Placentae from normotensive IUGR (n = 42) and appropriate for gestational age (AGA) pregnancies (n = 47) were collected and examined histologically. Clinical parameters were obtained from the medical records. Real-time quantitative PCR was performed to assess placental transcript abundance of VEGF, PGF, FLT1, ANGPT1, ANGPT2, and TEK normalized to a panel of reference genes. Associations of placental transcript abundance of the genes with maternal, placental, and neonatal parameters were tested.Results: Placental transcript abundance for VEGF (relative expression 10.81 versus 12.98, p < .001), PGF (12.14 versus 13.8, p < .001) and ANGPT2 (3.67 versus 9.55, p = .002) were significantly lower in IUGR placentae compared to AGA. The transcript level of VEGF showed significant negative correlation with birth weight (r = -0.419, p = .006), placental weight (r = -0.318, p = .040), placental length (r = -0.389, p = .011) and breadth (r = -0.308, p = .047) only in the IUGR group. Presence of histopathological features of hypoxia correlated with significantly higher transcript levels of PGF in IUGR placentae (12.6 versus 10.9, p = .046).Conclusion: The low levels of VEGF transcripts may be responsible for the impaired angiogenesis in IUGR placentae. The significance of higher relative expression of PGF in the presence of chronic hypoxia needs to be explored.

Placenta Creta: A Spectrum of Lesions Associated with Shallow Placental Implantation

Background

On placental histology, placenta creta (PC) ranges from clinical placenta percreta through placenta increta and accreta (clinical and occult) to myometrial fibers with intervening decidua. This retrospective study aimed to investigate the clinicopathologic correlations of these lesions.

Methods

A total of 169 recent consecutive cases with PC (group 1) were compared with 1661 cases without PC examined during the same period (group 2). The frequencies of 25 independent clinical and 40 placental phenotypes were statistically compared between the groups using chi-square test or analysis of variance where appropriate.

Results

Group 1 placentas, as compared with group 2 placentas, were statistically significantly (p < 0.05) associated with caesarean sections (11.2% vs. 7.5%), antepartum hemorrhage (17.7% vs 11.6.%), gestational hypertension (11.2% vs 4.3%), preeclampsia (11.8% vs 2.6%), complicated third stage of labor (18.9% vs 6.4%), villous infarction (14.2% vs 8.9%), chronic hypoxic patterns of placental injury, particularly the uterine pattern (14.8%, vs 9.6%), massive perivillous fibrin deposition (9.5% vs 5.3%), chorionic disc chorionic microcysts (21.9% vs 15.9%), clusters of maternal floor multinucleate trophoblasts (27.8% vs 21.2%), excessive trophoblasts of chorionic disc (24.3% vs 17.3%), segmental fetal vascular malperfusion (27.8% vs 19.9%), and fetal vascular ectasia (26.2% vs 15.2%).

Conclusion

Because of the association of PC with gestational hypertensive diseases, acute and chronic placental hypoxic lesions, increased extravillous trophoblasts in the chorionic disc, chorionic microcysts, and maternal floor trophoblastic giant cells, PC should be regarded as a lesion of abnormal placental implantation and abnormal trophoblast invasion rather than decidual deficiency only.

Low oxygen tension differentially regulates the expression of placental solute carriers and ABC transporters

Low oxygen concentration, or hypoxia, is an important physiological regulator of placental function including chemical disposition. Here, we compared the ability of low oxygen tension to alter the expression of solute carriers (SLC) and ABC transporters in two human placental models, namely BeWo cells and term placental explants. We found that exposure to low oxygen concentration differentially regulates transporter expression in BeWo cells, including downregulation of ENT1, OATP4A1, OCTN2, BCRP, and MRP2/3/5, and upregulation of CNT1, OAT4, OATP2B1, SERT, SOAT, and MRP1. Similar upregulation of MRP1 and downregulation of MRP5 and BCRP were observed in explants, whereas uptake transporters were decreased or unchanged. Furthermore, a screening of transcriptional regulators of transporters revealed that hypoxia leads to a decrease in the mRNA levels of aryl hydrocarbon receptor, nuclear factor erythroid 2-related factor 2, and retinoid x receptor alpha in both human placental models. These data suggest that transporter expression is differentially regulated by oxygen concentration across experimental human placental models.

Placental Findings in Postpartum Preeclampsia: A Comparative Retrospective Study

OBJECTIVE

Preeclampsia is a multifactorial placental disease that can occur after delivery. The pathophysiology of postpartum preeclampsia remains unknown. The objective was to describe placental findings in postpartum preeclampsia.

STUDY DESIGN

This is a case-control study, comparing the placental histologic findings in four groups of 30 patients with postpartum preeclampsia, early-onset preeclampsia, late-onset preeclampsia, and normotensive controls.

RESULTS

Placentas of postpartum preeclampsia had a mean placental weight not different from that of late-onset preeclampsia at a similar gestational age (479.0 ± 152.7 vs. 521.3 ± 144.1 g, p = 0.07); they showed a higher rate of acute deciduitis of 42.4% than early preeclampsia (5.7%, p < 0.01) or in controls (3.2%, p < 0.01); 18.2% had decidual arteriolopathy, with no significant difference with other groups. These placentas had fewer villous infarcts as compared with early preeclampsia (9.1 vs. 62.9%, p < 0.01) and less accelerated maturation of villi (24.2 vs. 74.3%, p < 0.01).

CONCLUSION

There were no significant differences for decidual arteriolopathy and villous infarcts among postpartum preeclampsia, late-onset preeclampsia, and the controls. This suggests that postpartum preeclampsia is more of a maternal disease in which the placenta may act as a priming effect in predisposed mothers and becomes clinically apparent after delivery.

Temporal heterogeneity of placental segmental fetal vascular malperfusion: timing but not etiopathogenesis

Clinicopathologic correlations of segmental villous avascularity and other histological lesions of segmental fetal vascular malperfusion (SFVM) were analyzed retrospectively to determine whether lesions of various durations reflect different etiopathogeneses. The frequencies of 25 independent clinical and 43 placental phenotypes were statistically compared by ANOVA or Chi-square among 3 groups containing a total of 378 placentas with SFVM: group 1 contained 44 cases of recent SFVM (endothelial fragmentation, villous hypovascularity by CD34 immunostain, and/or stromal vascular karyorrhexis); group 2 contained 264 cases of established SFVM (clusters of avascular villi); and group 3 contained 70 cases of remote SFVM (villous mineralization). Statistically significant differences among the three study groups (p Bonferroni < 0.002) were found in four clinical variables (gestational age, frequencies of macerated stillbirth, induction of labor, and cesarean section) and in five placental variables (frequencies of fetal vascular ectasia, stem vessel luminal vascular abnormalities, diffusely increased extracellular matrix in chorionic villi, chorionic disk extravillous trophoblast microcysts, and excessive extravillous trophoblasts in the chorionic disc). In summary, the absence of statistically significant differences between the study groups regarding the most common causes of SFVM (hypertensive conditions of pregnancy, diabetes mellitus, fetal anomalies, and clinical and pathological features of umbilical cord compromise) is evidence that the three types of SFVM reflect temporal heterogeneity rather than etiopathogenesis. This evidence can be used to date the onset of fetal vascular malperfusion before delivery or stillbirth. The coexistence of different SVFM lesions of various durations indicates ongoing or repeat occurrences of FVM rather than single episodes.

Mature Twin Neonates Exhibit Oxidative Stress via Nitric Oxide Synthase Dysfunctionality: A Prognostic Stress Marker in the Red Blood Cells and Umbilical Cord Vessels

Intrauterine hypoxic condition increases the generation of reactive oxygen species and fetal oxidative stress. Multiple pregnancy always bears an additional oxidative stress condition with severe complications, such as prematurity, structural abnormalities, delayed development and low birthweight. The umbilical cord (UC) vessels, along with circulating fetal red blood cells (RBCs), highly determine the oxygenation status of fetus and regulate the feto-placental circulation. As UC lacks innervation, the activation of the endothelial nitric oxide synthase (NOS3) is fundamental for proper NO production. Therefore, we aimed to study the NOS3 activation pathways along with damages to macromolecules in the endothelium of UC vessels and RBCs of mature non-discordant twins, in connection to major differences in their birth weight. We provide evidence that, under severe hypoxic conditions such as twin pregnancy, the NOS3-related NO production pathways are altered both in UC vessels and RBCs; moreover, the extent of changes is highly birthweight-specific. Furthermore, macromolecular damages are prominent in the RBCs and arteries compared to the vein, with a similar increase in the Arginase1 level, which is believed to play a role in NOS3 functionality, resulting in endothelial dysfunctionality, which might have relevance to the major etiologies of cardiovascular diseases in later life.

Is obesity in pregnancy associated with signs of chronic fetal hypoxia?

INTRODUCTION

The prevalence of obesity in pregnancy is increasing worldwide. Maternal obesity increases risks of severe fetal and neonatal complications. The underlying pathophysiological mechanisms are unclear. One possible contributing factor could be chronic fetal hypoxia. The aim of this study was to compare placentas from women with and without obesity with respect to placental lesions, which could reflect compensatory mechanisms in response to chronic fetal hypoxia as well as lesions possibly leading to chronic fetal hypoxia. In addition, levels of erythropoietin in cord blood were compared between offspring of lean and obese women.

MATERIAL AND METHODS

This cohort study included 180 women with uneventful, full-term, singleton pregnancies, out of which 91 lean women had a body mass index (BMI) of 18.5-24.9 kg/m² and 89 women had obesity (BMI ≥30 kg/m² ). Women were recruited at Södersjukhuset between 16 October 2018 and 2 December 2019. Placentas were investigated by two senior perinatal pathologists, who were blinded for maternal BMI. Cord blood was analyzed for levels of erythropoietin.

RESULTS

Levels of erythropoietin in cord blood increased with maternal BMI (P = .01, β = 0.97, 95% CI 0.27-1.68). There was no difference between placentas of obese and lean women in number of placental lesions reflecting chronic fetal hypoxia or in lesions that could possibly lead to chronic fetal hypoxia.

CONCLUSIONS

This study of term and uneventful pregnancies demonstrated a positive association between maternal obesity and concentrations of erythropoietin in cord blood at birth. This finding supports the hypothesis of chronic fetal hypoxia as a risk factor for complications in the pregnancies of obese women. There were no differences in lesions associated with hypoxia between placentas of obese and lean women.

Disorders of placental villous maturation in fetal death

Objective The aims of this study were to ascertain the frequency of disorders of villous maturation in fetal death and to also delineate other placental histopathologic lesions in fetal death. Methods This was a retrospective observational cohort study of fetal deaths occurring among women between January 2004 and January 2016 at Hutzel Women's Hospital, Detroit, MI, USA. Cases comprised fetuses with death beyond 20 weeks' gestation. Fetal deaths with congenital anomalies and multiple gestations were excluded. Controls included pregnant women without medical/obstetrical complications and delivered singleton, term (37-42 weeks) neonate with 5-min Apgar score ≥7 and birthweight between the 10th and 90th percentiles. Results Ninety-two percent (132/143) of placentas with fetal death showed placental histologic lesions. Fetal deaths were associated with (1) higher frequency of disorders of villous maturation [44.0% (64/143) vs. 1.0% (4/405), P < 0.0001, prevalence ratio, 44.6; delayed villous maturation, 22% (31/143); accelerated villous maturation, 20% (28/143); and maturation arrest, 4% (5/143)]; (2) higher frequency of maternal vascular malperfusion lesions [75.5% (108/143) vs. 35.7% (337/944), P < 0.0001, prevalence ratio, 2.1] and fetal vascular malperfusion lesions [88.1% (126/143) vs. 19.7% (186/944), P < 0.0001, prevalence ratio, 4.5]; (3) higher frequency of placental histologic patterns suggestive of hypoxia [59.0% (85/143) vs. 9.3% (82/942), P < 0.0001, prevalence ratio, 6.8]; and (4) higher frequency of chronic inflammatory lesions [53.1% (76/143) vs. 29.9% (282/944), P < 0.001, prevalence ratio 1.8]. Conclusion This study demonstrates that placentas of women with fetal death were 44 times more likely to present disorders of villous maturation compared to placentas of those with normal pregnancy. This suggests that the burden of placental disorders of villous maturation lesions is substantial.

Intrauterine Gardnerella vaginalis Infection Results in Fetal Growth Restriction and Alveolar Septal Hypertrophy in a Rabbit Model

Background: Gardnerella vaginalis (GV) is most frequently associated with bacterial vaginosis and is the second most common etiology causing intrauterine infection after Ureaplasma urealyticum. Intrauterine GV infection adversely affects pregnancy outcomes, resulting in preterm birth, fetal growth restriction, and neonatal pneumonia. The knowledge of how GV exerts its effects is limited. We developed an in vivo animal model to study its effects on fetal development. Materials and Methods: A survival mini-laparotomy was conducted on New Zealand rabbits on gestational day 21 (28 weeks of human pregnancy). In each dam, fetuses in the right uterine horn received intra-amniotic 0.5 × 10² colony-forming units of GV injections each, while their littermate controls in the left horn received sterile saline injections. A second laparotomy was performed seven days later. Assessment of the fetal pups, histopathology of the placenta and histomorphometric examination of the fetal lung tissues was done. Results: Three dams with a combined total of 12 fetuses were exposed to intra-amniotic GV, and 9 fetuses were unexposed. The weights of fetuses, placenta, and fetal lung were significantly lower in the GV group than the saline-inoculated control group [mean gross weight, GV (19.8 ± 3.8 g) vs. control (27.9 ± 1.7 g), p < 0.001; mean placenta weight, GV (5.5 ± 1.0 g) vs. control (6.5 ± 0.7 g), p = 0.027; mean fetal lung weight, GV (0.59 ± 0.11 g) vs. control (0.91 ± 0.08 g), p = 0.002. There was a two-fold increase in the multinucleated syncytiotrophoblasts in the placenta of the GV group than their littermate controls (82.9 ± 14.9 vs. 41.6 ± 13.4, p < 0.001). The mean alveolar septae of GV fetuses was significantly thicker than the control (14.8 ± 2.8 μm vs. 12.4 ± 3.8 μm, p = 0.007). Correspondingly, the proliferative index in the interalveolar septum was 1.8-fold higher in the GV group than controls (24.9 ± 6.6% vs. 14.2 ± 2.9%, p = 0.011). The number of alveoli and alveolar surface area did not vary between groups. Discussion: Low-dose intra-amniotic GV injection induces fetal growth restriction, increased placental multinucleated syncytiotrophoblasts and fetal lung re-modeling characterized by alveolar septal hypertrophy with cellular proliferative changes. Conclusion: This intra-amniotic model could be utilized in future studies to elucidate the acute and chronic effects of GV intrauterine infections.

Patterns of Placental Injury in Congenital Anomalies in Second Half of Pregnancy

BACKGROUND

Placental pathology in fetal congenital anomalies in second half of pregnancy is largely unknown.

METHODS

Twenty-six clinical and 45 independent placental phenotypes from pregnancies ≥20 weeks of gestation with congenital anomalies divided into 4 groups were retrospectively compared with analysis of variance or χ ² with 3 degrees of freedom and with Bonferroni correction for multiple comparisons: group 1 : 112 cases with heart malformations (with or without chromosomal anomalies), group 2 : 41 cases with abnormal karyotypes and anomalies other than heart malformations, group 3 : 87 cases with intrathoracic or intraabdominal mass-forming anomalies (mostly congenital diaphragmatic hernias and adenomatoid airway malformation), and group 4 : 291 miscellaneous cases with mostly skeletal, renal, and central nervous system anomalies not fulfilling the criteria of inclusion into groups 1 to 3.

RESULTS

Eight of 26 clinical (30.8%) and 16 of 45 (35.5%) placental phenotypes varied statistically significantly among the 4 groups (P <  .05), of those, 7 (26.9%) and 4 (8.9%), respectively, remained statistically significant after Bonferroni correction (P Bonferroni ≤  .002). Those placental phenotypes were placental weight, chorionic disc chorionic microcysts, fetal vascular ectasia, and luminal vascular abnormalities of chorionic villi.

CONCLUSIONS

Fetal anomalies in second half of pregnancy feature abnormal clinical phenotypes much more frequently than abnormal placental phenotypes. Chromosomal abnormalities with or without heart malformations tend to feature villous edema, and erythroblastosis of fetal blood, likely due to fetal heart failure. Mass-forming fetal anomalies feature placental histological lesions of shallow placental implantation, diffuse chronic hypoxic patterns of placental injury, and lesions of fetal vascular malperfusion, likely stasis-induced.

Placental MRI: Developing Accurate Quantitative Measures of Oxygenation

The Human Placenta Project has focused attention on the need for noninvasive magnetic resonance imaging (MRI)-based techniques to diagnose and monitor placental function throughout pregnancy. The hope is that the management of placenta-related pathologies would be improved if physicians had more direct, real-time measures of placental health to guide clinical decision making. As oxygen alters signal intensity on MRI and oxygen transport is a key function of the placenta, many of the MRI methods under development are focused on quantifying oxygen transport or oxygen content of the placenta. For example, measurements from blood oxygen level-dependent imaging of the placenta during maternal hyperoxia correspond to outcomes in twin pregnancies, suggesting that some aspects of placental oxygen transport can be monitored by MRI. Additional methods are being developed to accurately quantify baseline placental oxygenation by MRI relaxometry. However, direct validation of placental MRI methods is challenging and therefore animal studies and ex vivo studies of human placentas are needed. Here we provide an overview of the current state of the art of oxygen transport and quantification with MRI. We suggest that as these techniques are being developed, increased focus be placed on ensuring they are robust and reliable across individuals and standardized to enable predictive diagnostic models to be generated from the data. The field is still several years away from establishing the clinical benefit of monitoring placental function in real time with MRI, but the promise of individual personalized diagnosis and monitoring of placental disease in real time continues to motivate this effort.

Placental Abnormalities Associated With Childbirth

Pathologists are faced with a variety of problems when considering placental tissue in cases of stillbirth. It is recognized that there are changes which occur following fetal demise and which can complicate the assessment and may coexist with other morphological changes. It is recognized that up to 25% of stillbirths may have a recognizable abnormality causing fetal demise. A systematic review of placental tissue allows many of these disorders to be identified. This review considers macroscopic and microscopic features of placental pathology in stillbirth together with clinicopathological correlation. Stillbirth definitions, general aspects of macroscopic assessment of placentas, placental changes after fetal demise, and some recognizable causes of fetal demise are considered.

Predictive value of cervical cytokine, antimicrobial and microflora levels for pre-term birth in high-risk women

Spontaneous preterm birth (sPTB, delivery <37 weeks gestation), accounts for approximately 10% of births worldwide; the aetiology is multifactorial with intra-amniotic infection being one contributing factor. This study aimed to determine whether asymptomatic women with a history of sPTB or cervical surgery have altered levels of inflammatory/antimicrobial mediators and/or microflora within cervical fluid at 22-24 weeks gestation. External cervical fluid was collected from women with history of previous sPTB and/or cervical surgery at 22-24 weeks gestation (n = 135). Cytokine and antimicrobial peptides were measured on a multiplex platform or by ELISA. qPCR was performed for detection of 7 potentially pathogenic bacterial species. IL-8 and IL-1β levels were lower in women who delivered preterm compared to those who delivered at term (IL-8 P = 0.02; IL-1β P = 0.04). There were no differences in elafin or human beta defensin-1 protein levels between the two groups. Multiple bacterial species were detected in a higher proportion of women who delivered preterm than in those who delivered at term (P = 0.005). Cervical fluid IL-8 and IL-1β and microflora have the potential to be used as biomarkers to predict sPTB in high risk women.

Segmental villous mineralization: A placental feature of fetal vascular malperfusion

INTRODUCTION

This retrospective analysis was performed to find out if clusters of mineralized chorionic villi can be regarded as an independent feature of fetal vascular malperfusion (FVM).

METHODS

Of all 1698 placentas reviewed by the author during the last 10 years, 39 (2.3%) showed clusters of mineralized chorionic villi (Group 1), 100 cases (5.9%) showed randomly scattered mineralized chorionic villi with without clustering (Group 2), and the remaining 1559 placentas showed no villous mineralization (comparative Group 3). In doubtful cases, histochemistry stains were performed to determine the pattern of villous mineralization. Twenty three independent clinical and 43 placental variables were statistically compared among the groups: descriptive statistics (Chi-square, Fisher test or signed rank test), and logistics regression model.

RESULTS

Clinically, Group 1 featured shorter gestational age than Group 2, and in addition to shorter gestational age, more common oligohydramnios, polyhydramnios, induction of labor, macerated stillbirth and fetal growth restriction than Group 3. Of placental variables, fetal vascular ectasia, and clusters of avascular chorionic villi were more common in Group 1 than in Group 2, and in addition, segmental villous stromal vascular karyorrhexis was more common than in Group 3. By the logistics regression mode, segmental villous mineralization was independently associated with other histological features of FVM as a group and particularly with clusters of sclerotic chorionic villi.

DISCUSSION

FVM is characterized by temporal heterogeneity, i.e. coexistence of lesions of various duration, and strongly and independently correlates with clusters of mineralized chorionic villi. Therefore, segmental villous mineralization should be included into the category of segmental FVM. It can be seen even in totally fibrotic placentas of prolonged stillbirth when other histological features of segmental vascular malperfusion can be obscured by global villous sclerosis.