Role of the Placenta in Perinatal Pathology (Revisited)

The significance of Syndecan 1, a new marker for endothelial dysfunction, in cases of fetal growth retardation

PROBLEM

In the current study we aimed to investigate Syndecan 1 (SDC1) levels in pregnant women diagnosed with fetal growth restriction (FGR) and the relationship between SDC1 levels and clinical and doppler parameters in FGR cases associated with endothelial dysfunction, angiogenesis and uteroplacental insufficiency METHOD OF STUDY: A total of 90 pregnant women included in the study, (45 with FGR, 45 healthy control) matched by week of gestation and maternal age. Venous blood samples were collected and plasma concentrations of SDC1 were determined by a specific immunoassay. Doppler examination was performed to evaluate the relationship between the SDC1 levels and placental blood supply.

RESULTS

Doppler parameters; mean UtA-PI (p < .001), CPR (p = .002) and CPUR (p < .001) were different between the groups, however MCA PI, umbilical artery PI and umbilical artery S/D were not (p > .05). While gestational age at delivery, birth weight, APGAR score at 1 and 5 min were significantly lower (all, p < .001) in the study group, non-reassure fetal heart rate tracing (p = .09) and NICU admission (p = .02) were significantly higher. SDC 1 level was 2,00 ± 1,47 ng/mL and 2,34 ± 1,12 ng/mL in the FGR and control groups, respectively (p = .008). In the study group SDC 1 level was 1,69 ± 2,00 in those with gestational age below 32 weeks and 2,13 ± 1,18 in those with gestational age above 32 weeks and there was a statistically significant difference between the groups (p = .015). Plasma SDC 1 concentration of 2,1850 ng/mL or less had a sensitivity of 70%, a specificity of 72%, area under the ROC curve .65 (p < .005).

CONCLUSIONS

Low maternal plasma SDC1 level may be associated with placental insufficiency and FGR. Low levels of SDC1 may be helpful as a predictor for the development of FGR during gestation.

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.

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.

Do Increased Intra-alveolar Squamous Cells at Autopsy Correlate With Acute Fetal Asphyxia?

It is a generally held concept that finding increased aspirated amniotic fluid squames at autopsy supports a diagnosis of acute fetal asphyxia, the massive aspiration of squames being an indicator of terminal gasping. To evaluate this concept, we identified autopsies on 15 third-trimester stillborns with clinical acute placental abruption (acute asphyxia); 13 also had thymic petechiae and none had severe acute thymic involution, findings also supporting acute asphyxia. Thirty third-trimester stillborns with findings supporting a subacute or chronic mode of death, including severe thymic involution and absence of thymic petechiae, comprised the comparison group. Intra-alveolar squames were scored as 0, no squames; 1+, scattered squames singly or in small groups; and 2+, squames in many alveoli, at least focally in compacted clusters. In all cases, the squames were patchily distributed, and none received a score of 0. In the abruption group, the intra-alveolar squames were scored as 1+ in 12 (80%) and as 2+ in 3 (20%) cases, while in the comparison group, the squames were scored as 1+ in 20 (67%) and 2+ in 10 (33%) cases (P = NS). There was also no difference in the quantification of intra-alveolar squames in term compared to preterm stillborns. In conclusion, quantification of intra-alveolar squames did not aid in separating an acute mode of death (acute asphyxia) from subacute or chronic modes of death.

Chorangiosis of Chorionic Villi: What Does It Really Mean?

Chorangiosis has been regarded as a result of low-grade placental hypoxia associated with pregnancy risk factors and abnormal outcomes. It is unknown whether these are a consequence of chorangiosis itself or of associated other placental pathology.Context.—

To prove that chorangiosis itself does not portend an increased risk for pregnancy unless associated with other placental pathology.Objective.—

This retrospective statistical study analyzes 1231 consecutive placentas with diffuse or focal hypervascularity of chorionic villi: 328 with preuterine pattern of chronic hypoxic placental injury (group 1), 297 with uterine type of chronic hypoxic placental injury (group 2), and 606 cases with chorangiosis (group 3) not fulfilling the inclusion criteria for groups 1 or 2.Design.—

Group 2, with 33 cases of chorangiosis (11.1%), featured 10 and 11 statistically significant highest percentages of abnormal clinical and placental variables, respectively; group 3 featured the highest percentages of multiple pregnancy, the heaviest placentas, and the most common acute chorioamnionitis, fetal inflammatory response; and group 1 had the highest proportion of mild erythroblastosis of fetal blood. When comparing groups 1 and 3, 21 of 29 clinical risk factors/outcomes (72.4%) and 30 of 41 placental variables (73.2%) were more common in group 1.Results.—

Presence of diffuse hypoxic patterns of placental injury adds prognostically negative significance to increased vascularity of chorionic villi. Chorangiosis without those patterns portends minimal risk for the pregnancy, and is associated with significantly fewer pregnancy risk factors, abnormal outcomes, and other placental abnormalities.Conclusions.—

Relation of placental diagnosis in stillbirth to fetal maceration and gestational age at delivery

AIM

To study the relation of retention of dead fetus resulting in its maceration and gestational age at delivery to placental diagnosis.

METHODS

Some 75 clinicoplacental phenotypes have been retrospectively analyzed in 520 consecutive stillbirths, 329 macerated and 191 nonmacerated, and at three gestational age interval cohorts (330 second trimester, 102 preterm third trimester, and 88 term). Chi-square and clustering methods (Ward dendrograms and multidimensional scaling) were used for statistical analysis.

RESULTS

Maternal diabetes mellitus, induction of labor, fetal growth restriction, various umbilical cord abnormalities, and placental clusters of sclerotic/hemosiderotic chorionic villi were more common in macerated stillbirths, while clinicoplacental signs and symptoms of ascending infection and placental abruption, i.e., retroplacental hematoma, premature rupture of membranes, and acute chorioamnionitis in nonmacerated stillbirths. Placental abnormalities were less common in the second trimester, other than the acute chorioamnionitis. Patterns of chronic hypoxic placental injury were common in preterm third trimester, while signs of in-utero hypoxia (abnormal cardiotocography, meconium, and histological erythroblastosis of fetal blood) in term pregnancy. In addition to classical statistics, the clustering analyses added new information to placental investigation of cause of stillbirth.

CONCLUSIONS

Macerated third trimester stillbirths have multifactorial etiology more likely than the second trimester stillbirths and the likely stasis-induced fetal thrombotic vasculopathy secondary to occult umbilical cord compromise should be sought in placental investigation in such cases. Nonmacerated stillbirths are associated with ascending infection and placental abruption.

Third trimester fetal demise occurring at time of delivery: correlation of autopsy findings and placental pathology with emphasis on antenatal central nervous system injury

OBJECTIVE

Third trimester fetal deaths occurring in the hospital at the time of delivery are unusual. We report an autopsy series of such cases with emphasis on neuropathological injury and other lesions predating delivery.

METHODS

We identified autopsies performed on third trimester fetuses documented to be alive shortly before delivery, but that expired during, or very close to, time of delivery, and we correlate autopsy and placental findings. Fetuses with major congenital anomalies were excluded.

RESULTS

Ten cases were identified (6 term, 4 preterm). All were delivered by cesarean section and had attempted resuscitation. Established or recent brain injury was identified in 9 of 10 cases, including 3 with established neuronal damage and 1 with periventricular leukomalacia. Additional autopsy findings included thymic involution in eight (five mild; three severe), myocardial infarcts in two; intrathoracic petechiae in five, and ascites or pleural or pericardial effusions in six. Severe thymic involution and myocardial infarcts correlated with established brain injury. Placental lesions adaptive to decreased oxygenation (increased nucleated red blood cells or villous hypervascularity) were seen in five cases and correlated with established brain injury. Acute chorioamnionitis with funisitis was present in one, and chronic inflammatory placental lesions were present in six.

CONCLUSIONS

These findings indicate brain injury predated the time period immediately before delivery in 9 of 10 fetuses, and in the fetuses with established brain injury the onset of acute illness was possibly >72 h before delivery.

Perinatal pathology: practice suggestions for limited-resource settings

The practice of perinatal pathology in much of the world suffers, as do all subspecialties of anatomic pathology, from inadequate resources (equipment, consumables, and both professional and technical personnel), from lack of education (not only of the pathologist but also of the clinicians responsible for sending the specimens, and the technicians processing the specimens), and from lack of appropriate government sector support. Perinatal pathology has significant public health-related utility and should be championing its service by providing maternal and fetal/infant mortality and morbidity data to governmental health ministries. It is with this pathologic data that informed decisions can be made on health-related courses of action and allocation of resources. These perinatal pathology data are needed to develop appropriate public health initiatives, specifically toward achieving the Millennium Developmental Goals as the best way to effectively decrease infant and maternal deaths and to determine causes of perinatal mortality and morbidity. The following overview will focus on the utility of perinatal pathology specifically as related to its public health function and will suggest methods to improve its service in resource-poor settings. This article is offered not as a critique of the current practice that most pathologists find themselves working in globally, but to provide suggestions for improving perinatal pathology services, which could be implemented with the limited available resources and manpower most pathology departments currently have. In addition, we offer suggestions for graded improvements ("ramping up") over time.

Hypoxic patterns of placental injury: a review

CONTEXT

In utero hypoxia is an important cause of perinatal morbidity and mortality and can be evaluated retrospectively to explain perinatal outcomes, to assess recurrence risk in subsequent pregnancies, and to investigate for medicolegal purposes by identification of many hypoxic placental lesions. Definitions of some placental hypoxic lesions have been applied relatively liberally, and many of them are frequently underreported. Objectives To present a comprehensive assessment of the criteria for diagnosing acute and chronic histologic features, patterns, and lesions of placental and fetal hypoxia and to discuss clinicopathologic associations and limitations of the use thereof. The significance of lesions that have been described relatively recently and are not yet widely used, such as laminar necrosis; excessive, extravillous trophoblasts; decidual multinucleate extravillous trophoblasts; and, most important, the patterns of diffuse chronic hypoxic preuterine, uterine, and postuterine placental injury and placental maturation defect, will be discussed.

DATA SOURCES

Literature review.

CONCLUSIONS

The placenta does not respond in a single way to hypoxia, and various placental hypoxic features should be explained within a clinical context. Because the placenta has a large reserve capacity, hypoxic lesions may not result in poor fetal condition or outcome. On the other hand, very acute, in utero, hypoxic events, followed by prompt delivery, may not be associated with placental pathology, and many poor perinatal outcomes can be explained by an etiology other than hypoxia. Nevertheless, assessment of placental hypoxic lesions is helpful for retrospective explanations of complications in pregnancy and in medicolegal investigation.

Is assisted reproduction associated with abnormal placentation?

Artificial reproductive technologies (ART) and conception following a period of untreated infertility (>1 year) are independently associated with increased pregnancy complications in both singleton and multiple pregnancies. It is unknown if placental dysfunction associated with macroscopic and/or microscopic histological discrepancies might explain some of these variances. Our aim was to compare the histopathology of placentae from singleton pregnancies belonging to 3 groups, as follows: conception as a result of ART; spontaneous conception (<1 year of trying); and conception following untreated infertility (>1 year). Pathological examination of placentae from singleton pregnancies of nonsmoking, age-matched primiparous women with no significant medical history and no known uterine congenital anomalies was performed by a single pathologist blinded to the groups. Features were compared using analysis of variance and chi-square tests. A total of 89 placental pathology reports were available (control  =  39, infertility  =  17, ART  =  33). The mean placental thickness was significantly higher in the ART group when compared to the spontaneous conception group (P  =  0.02). There were significantly more placental hematomas in the ART group (P  =  0.04) compared to the other groups. There were no significant differences in rates of abnormal placental shapes or abnormal cord insertions. There were no statistically significant differences in the incidence of microscopic placental lesions, nor were there any statistically significant differences in the incidence of macroscopic and microscopic placental lesions between the infertility group and the other groups. Placentae of ART pregnancies show significantly increased thickness and a higher incidence of hematomas. Increased placental thickness has previously been linked to increased perinatal risk.

Alterações anatomopatológicas da placenta e variações do índice de Apgar

OBJETIVOS: descrever possíveis alterações anatomopatológicas placentárias associadas à hipóxia fetal, avaliada pelo índice de Apgar. MÉTODOS: foram estudadas 167 placentas de partos realizados no Hospital Escola da Universidade Federal do Triângulo Mineiro, em Uberaba, através da análise macroscópica e microscópica, e de informações clínicas obtidas de prontuários. O índice de Apgar menor que sete foi o parâmetro utilizado para se diagnosticar hipóxia fetal. RESULTADOS: foram encontradas alterações placentárias compatíveis com hipertensão e infiltrado inflamatório. As placentas com alterações compatíveis com baixo fluxo sanguíneo cursaram mais freqüentemente com fetos com índice de Apgar <7 no 5º minuto (p=0,017). CONCLUSÕES: pode existir uma relação entre alterações placentárias e hipóxia fetal evidenciada pelo índice de Apgar. Portanto, o exame anatomopatólogico da placenta poderia ser utilizado para esclarecer causas de hipóxia perinatal não evidenciadas na clínica.

Placental features in preterm infants with periventricular leukomalacia

OBJECTIVE

Evaluation of the placenta provides some important insights into pathophysiologic changes that take place during the prenatal and intrapartum process. We investigated the relationship between placental findings and periventricular leukomalacia (PVL) to obtain a better understanding of its cause.

METHODS

Thirty-two preterm infants with PVL delivered before 34 weeks' gestation, between 1990 and 1999, were classified into 4 groups according to the onset of brain injury assumed from ultrasonographic presentation and clinical course: 2 Antenatal, 22 Peripartum, 5 Postnatal, and 3 in an unknown time of onset group. We evaluated the gross and histopathologic features of the placentas of each group and compared them with those of a control group matched by birth weight and gestational age in terms of the frequency of major placental findings. Potential confounding factors were controlled in logistic regression analyses.

RESULTS

Gross lesions with disturbance of uteroplacental circulation, including massive retroplacental hematoma, extensive infarction or thrombosis, and marked basal or perivillous fibrin deposition, were observed more frequently in the Antenatal + Peripartum combined subgroup than in the controls (41.7% vs 13.7%). Placentas from the Antenatal + Peripartum subgroup also demonstrated a significantly higher frequency of ischemic changes in villi, based on histopathologic examination, as compared with the control group (54.2% vs 13.7%). These associations remained after adjustment for confounding factors in logistic regression analyses (odds ratio: 4.04, 95% confidence interval: 1.40-11.67; and odds ratio: 7.28, 95% confidence interval: 2.50-21.20; respectively). Frequencies of chorioamnionitis and twin placentation tended to be higher in PVL cases than in the controls, although the differences were not statistically significant (46.9% vs 37.9%, 37.5% vs 20.0%, respectively).

CONCLUSIONS

These results suggest that disturbed placental circulation underlies the development of PVL in the majority of cases with prenatal and peripartum brain injury. In chorioamnionitis cases, certain additional factors were suggested in the genesis of PVL. Thus, placental examination is essential for elucidating the pathophysiologic changes leading to PVL in the perinatal process.

Early neonatal brain injury in histologic chorioamnionitis

The relation between clinical or histologic chorioamnionitis and early neonatal adverse neurologic outcome was investigated (n = 483). Histologic, but not clinical, evidence of chorioamnionitis was found to be a significant predictor of periventricular echodensity (odds ratio, 2.4; 95% CI, 1.8-3.2), echolucency (3.3; 1.9-5.6), ventriculomegaly (2.7; 1.8-4.2), intraventricular hemorrhage > or =3 (3.5; 2.4-5.2), and seizures (2.3; 1.4-3.7).

Chronic intrauterine meconium aspiration causes fetal lung infarcts, lung rupture, and meconium embolism

Three neonates with chronic intrauterine meconium aspiration are reported. All had distinctive subpleural plate-infarcts of the lungs caused by meconium-induced vasoconstriction of peripheral preacinar arteries. These vessels showed plexogenic arteriopathy with medionecrosis and obliterative hyaline sclerosis. Organized thrombi and systemic-pulmonary arterial anastomoses were numerous. The infarcts contained inspissated meconium with a granulomatous reaction. In one case, lung rupture occurred, causing meconiumthorax and meconium embolism to hilar lymphatics and lymph nodes; this suggests that particulate meconium may enter the circulation. This fetus had rubella and probable acute twin-twin transfusion following the intrauterine death of the co-twin. The cause of the hypoxia that led to intrauterine passage of meconium in the other cases is unknown. Meconium-stained amniotic fluid was noted in only one case.

Small thymus in very low birth weight infants born to mothers with subclinical chorioamnionitis

Chorioamnionitis, a major cause of preterm birth with significant neonatal morbidity and mortality, frequently occurs in mothers who are free of symptoms. A combined clinical, radiologic, and pathologic study of 129 very low birth weight infants indicated a significant association between a markedly decreased thymic size at birth and subclinical chorioamnionitis.