Villous oedema of the placenta: a clinicopathological study

Impact of Co-Occurrence of Obesity and SARS-CoV-2 Infection during Pregnancy on Placental Pathologies and Adverse Birth Outcomes: A Systematic Review and Narrative Synthesis

Obesity is a risk factor for severe COVID-19 disease during pregnancy. We hypothesized that the co-occurrence of high maternal body mass index (BMI) and gestational SARS-CoV-2 infection are detrimental to fetoplacental development. We conducted a systematic review following PRISMA/SWiM guidelines and 13 studies were eligible. In the case series studies (n = 7), the most frequent placental lesions reported in SARS-CoV-2(+) pregnancies with high maternal BMI were chronic inflammation (71.4%, 5/7 studies), fetal vascular malperfusion (FVM) (71.4%, 5/7 studies), maternal vascular malperfusion (MVM) (85.7%, 6/7 studies) and fibrinoids (100%, 7/7 studies). In the cohort studies (n = 4), three studies reported higher rates of chronic inflammation, MVM, FVM and fibrinoids in SARS-CoV-2(+) pregnancies with high maternal BMI (72%, n = 107/149; mean BMI of 30 kg/m2) compared to SARS-CoV-2(−) pregnancies with high BMI (7.4%, n = 10/135). In the fourth cohort study, common lesions observed in placentae from SARS-CoV-2(+) pregnancies with high BMI (n = 187 pregnancies; mean BMI of 30 kg/m2) were chronic inflammation (99%, 186/187), MVM (40%, n = 74/187) and FVM (26%, n = 48/187). BMI and SARS-CoV-2 infection had no effect on birth anthropometry. SARS-CoV-2 infection during pregnancy associates with increased prevalence of placental pathologies, and high BMI in these pregnancies could further affect fetoplacental trajectories.

Histopathology of the fetal inflammatory response to intra-amniotic pathogens

Obstetric endorsement of the utility of placental histologic examination remains infrequent, especially from obstetricians who do not have a placental pathologist as part of their own local clinical care team. Placental pathologic examinations are viewed as useless if they do not provide answers to urgent clinical questions. Increasingly, however, it is appreciated that while placental analysis should be considered with regard to its longer term value; results can assess lifelong risks of a wide range of diseases that have been tied to prenatal exposures (e.g., [1]), including distinguishing sex-specific differences in those risks. (e.g., [2]) This review will focus solely on acute fetal (?) inflammation, more specifically, the fetal neutrophil responses in umbilical cord, chorionic plate vessels and to some degree, the fetal system as a whole. This histologic fetal inflammatory response is often the most readily accessible aspect of "FIR" piece of FIRS (the fetal inflammatory response syndrome). Some researchers have defined FIRS by a combination of both cytokine (especially IL-6) levels and the histopathologic FIR (Musilova et al., 2018) [3]. As we and others have noted, many histology based FIR cases, even those associated with neurodevelopmental outcomes such as cerebral palsy, are clinically silent.(e.g., [4]) Current clinical diagnostic criteria may have high specificity as they are very good at identifying non-FIR cases. However, that high specificity is coupled with very low specificity, identifying only 10% of FIR (Doty et al., 2018 Jul) [5]. Our aim is to provide a conceptual framework for the readers of the journal to better understand how to answer the following questions: What is a neutrophil and how is it important in FIR? What is the differential diagnosis for histologic FIR? How long has there been FIR? What secondary processes may have been recruited (and when) to contribute to the final pathology and pathophysiology of the given pregnancy?

Alteraciones morfológicas de las vellosidades placentarias asociadas a malformaciones fetales múltiples del sistema esquelético

OBJETIVOS: describir y cuantificar alteraciones morfológicas en vellosidades placentarias de embarazadas cuyo feto desarrolló malformaciones esqueléticas múltiples. MÉTODOS: se analizaron cuatro placentas de abortos terapéuticos a las 13, 16, 20 y 38 semanas de gestación. Estas se compararon con placentas normales a la misma edad de gestación de abortos electivos por indicación médico legal. Tinción de hematoxilinaeosina se aplicó a 10 láminas de 5 regiones de cada placenta utilizando un protocolo con 4 variables cuantitativas: madurez, cambios fibrinoides, edema y fibrosis estromal y una variable cualitativa: trombosis. Los resultados cuantitativos se analizaron utilizando el análisis de varianza (ANAVAR) según arreglo completamente aleatorizado y el test de Tukey. Para la variable cualitativa se aplicó la prueba de tendencia para datos correlacionados. Se empleó el software statistix 8.0 y SAS 9.0 para Windows. RESULTADOS: existen diferencias significativas (p<0,05) entre las placentas asociadas a malformaciones múltiples del sistema esquelético y las placentas control en relación a las variables cuantitativas. No se encontraron diferencias significativas (p>0,05) en relación a la variable cualitativa. CONCLUSIONES: la población de vellosidades placentarias asociadas a malformaciones múltiples del sistema esquelético presentó un alto porcentaje de alteraciones indicando que la barrera placentaria está dañada afectando el intercambio de gases, nutrientes y metabolitos durante el desarrollo del feto.

Placental biopsy by frozen section: does it have a role in evaluation of fetal well-being?

AIM

To assess the effectiveness of post-partum placental biopsy and frozen section evaluation in diagnosing pregnancy disorders.

STUDY DESIGN

Between January and July 1998, biopsies were carried out on 100 newly delivered placentas. Biopsies were carried out using a 14-gauge needle, and frozen section evaluations were reviewed. These were compared to the standard evaluation of histological evaluation of the whole placenta sections. Specimens were evaluated by standard placental pathologic criteria.

RESULTS

Villous oedema which is associated with antenatal hypoxia was observed with a sensitivity of 78%, and specificity of 97%, yielding a positive predictive value of 84% in frozen section compared to standard placental evaluation. No statistical difference was observed in the evaluation of dysmaturity, intravillous fibrin agglutination and chronic villitis between frozen sectioning and whole placenta sections. Increased syncytial knots were detected with a sensitivity of 45% and specificity of 98%.

CONCLUSION

Placental biopsy by frozen sectioning might be a useful and quick method of evaluation for placental pathology. Theoretically, fetal status could be more precisely evaluated by combining prenatal placental biopsy by permanent section with conservative ante-partum well-being tests.

The significance of the placenta in assessment of the newborn

The placenta may harbor many diagnostic tools available for the care of ill neonates. Such tools enable fine-tuning of diagnoses or even the establishment of diagnoses not considered during the investigation and care of the newborn. For this reason, obstetricians, pediatricians, and pathologists should all be familiar with common placental diagnoses so that sharing of the available data among these specialists may, in many cases, provide supportive and diagnostic information critical to the management of the newborn.

A topographical and clinical approach to examination of the placenta

Placental examination can be frustrating because of a perceived lack of usefulness and other limitations. A systematic examination employing a topographic approach that will eliminate gross omissions is described. This approach is used at the time of gross and histological examination. Histologically, the umbilical cord is examined from the surface to the inside, while the amniochorial membranes and placental disc are examined from the foetal to maternal surfaces. It is possible to accrue useful information when the placenta is examined this way. This information then can be correlated with the clinical details and indications for the placental examination.

Stillbirths and intrauterine infection, histologic chorioamnionitis and microbiological findings

OBJECTIVE

To analyze whether placental inflammation is associated with stillbirth in Zimbabwe.

METHOD

Placentas from 66 stillbirths (> 22 weeks' gestation; patients with congenital malformations, diabetes or preeclampsia were excluded) and 66 term live births were studied for the presence and severity of chorioamnionitis. The morphological results were compared with earlier presented microbiological findings in the same material.

RESULTS

Chorioamnionitis was present in 79% of stillbirths and 30% of live births (O.R. 8.5, 95% C.I. 4.0-18). Nine percent of stillbirths but no live births presented vasculitis of the chorionic plate, which verified an inflammatory response from the infant (O.R. 14, 95% C.I. 2.8-72). The same types of microorganisms were isolated from stillbirths and liveborns, but Escherichia coli and group B streptococci were more frequent among stillbirths.

CONCLUSIONS

Morphological chorioamnionitis occurred 2.6 times more often in women with stillbirths than in women with live births. In 9% of stillbirths the infant showed an inflammatory response. Thus the infant was alive when the infection occurred and it is therefore reasonable to assume that infection was the cause of death.

Placental water content and distribution

The percentage of total placental water (%H2O(T)), maternal (%MBV) and fetal (%FBV) blood volumes, non-vascular extracellular (%EW) and intracellular (%IW) water, and villous histology were studied in placentas from 12 normal term pregnancies after a normal vaginal delivery, 19 caesarean sections at term after a normal pregnancy and history of a previous caesarean section and 47 caesarean sections at term or preterm due to pregnancy complications. Values were derived from change in placental dry weight, maternal and fetal haemoglobin content and 51CrEDTA space after incubation of placental fragments. Normal ranges (mean +/- SD) after term vaginal delivery were: H2O(T) 83.9 +/- 0.2%, MBV 10.9 +/- 0.2%, FBV 7.4 +/- 0.9%, EW 57.3 +/- 1.3% and IW 11.2 +/- 0.6%. %H2O(T) was higher after caesarean section; other measurements were not affected. There were no differences between placentas after 33-37 and after 38-42 weeks gestation. Three of eight placentas after rhesus incompatibility had %H2O(T) above the mean +2SD of term placentas and five of 17 IUGR placentas were below the mean -2SD. The remaining placentas following maternal pre-eclampsia, hypertension, or diabetes had no apparent alteration in %H2O(T). A blind histological diagnosis of 'true' oedema was associated with both a significantly high %IW and %H2O(T). Perhaps this is due to alteration in placental cell volume regulation in certain situations.