Clinical significance of placental examination in perinatal medicine

Assessment of pregnancy dietary intake and association with maternal and neonatal outcomes

BACKGROUND

Maternal dietary habits are contributors of maternal and fetal health; however, available data are heterogeneous and not conclusive.

METHODS

Nutrient intake during pregnancy was assessed in 503 women with uncomplicated pregnancies, using the validated Food Frequency Questionnaire developed by the European Prospective Investigation into Cancer and Nutrition (EPIC-FFQ).

RESULTS

In all, 68% of women had a normal body mass index at the beginning of pregnancy, and 83% of newborns had an appropriate weight for gestational age. Maternal pre-pregnancy body mass index (BMI), gestational weight gain (GWG), and placental weight were independently correlated with birth weight. GWG was not related to the pre-pregnancy BMI. EPIC-FFQ evaluation showed that 30% of women adhered to the European Food Safety Authority (EFSA) ranges for macronutrient intake. In most pregnant women (98.1%), consumption of water was below recommendations. Comparing women with intakes within EFSA ranges for macronutrients with those who did not, no differences were found in BMI, GWG, and neonatal or placental weight. Neither maternal nor neonatal parameters were associated with the maternal dietary profiles.

CONCLUSIONS

In our population, maternal pre-pregnancy BMI, GWG, and placental weight are determinants of birth weight percentile, while no association was found with maternal nutrition. Future studies should explore associations through all infancy.

IMPACT

Maternal anthropometrics and nutrition status may affect offspring birth weight. In 503 healthy women, maternal pre-pregnancy body mass index (BMI), gestational weight gain (GWG), and placental weight were independently correlated to neonatal birth weight. GWG was not related to the pre-pregnancy BMI. In all, 30% of women respected the EFSA ranges for macronutrients. Neither maternal nor neonatal parameters were associated with maternal dietary profiles considered in this study. Maternal pre-pregnancy BMI, GWG, and placental weight are determinants of neonatal birth weight percentile, while a connection with maternal nutrition profiles was not found.

MYCN Amplified Relapse Following Resolution of MYCN Nonamplified 4S Neuroblastoma With Placental Involvement: A Case Report and Review of the Literature

Congenital neuroblastoma with placental involvement is exceptionally rare, but mortality is high. Detailed examination of placenta including MYCN amplification and segmental chromosomal aberrations should be performed in all suspected cases, as it is noninvasive and readily available. Maternal dissemination has not been reported. In this manuscript, we describe an infant with placental diagnosis of MYCN nonamplified congenital neuroblastoma. This is the first report of a recurrence of congenital 4S neuroblastoma following resolution in which MYCN amplification is only detected in the recurrence. Germline sequencing using a large comprehensive cancer panel did not reveal variants in candidate cancer predisposition genes.

The frequency and type of placental histologic lesions in term pregnancies with normal outcome

Objective To determine the frequency and type of histopathologic lesions in placentas delivered by women with a normal pregnancy outcome. Methods This retrospective cohort study included placental samples from 944 women with a singleton gestation who delivered at term without obstetrical complications. Placental lesions were classified into the following four categories as defined by the Society for Pediatric Pathology and by our unit: (1) acute placental inflammation, (2) chronic placental inflammation, (3) maternal vascular malperfusion and (4) fetal vascular malperfusion. Results (1) Seventy-eight percent of the placentas had lesions consistent with inflammatory or vascular lesions; (2) acute inflammatory lesions were the most prevalent, observed in 42.3% of the placentas, but only 1.0% of the lesions were severe; (3) acute inflammatory lesions were more common in the placentas of women with labor than in those without labor; (4) chronic inflammatory lesions of the placenta were present in 29.9%; and (5) maternal and fetal vascular lesions of malperfusion were detected in 35.7% and 19.7%, respectively. Two or more lesions with maternal or fetal vascular features consistent with malperfusion (high-burden lesions) were present in 7.4% and 0.7%, respectively. Conclusion Most placentas had lesions consistent with inflammatory or vascular lesions, but severe and/or high-burden lesions were infrequent. Mild placental lesions may be interpreted either as acute changes associated with parturition or as representative of a subclinical pathological process (intra-amniotic infection or sterile intra-amniotic inflammation) that did not affect the clinical course of pregnancy.

The structure and utility of the placental pathology report

The placenta is one of the most exciting organs. It is dynamic; its morphology and function continuously develop and adjust over its brief life span. It mediates the physiology of two distinct yet highly interconnected individuals. The pathology that develops in the placenta, and the adaptations the placenta undergoes to mitigate this pathology, may influence the later life health of the mother and baby (Circ Res, 116, 2015, 715; Hum Reprod Update, 17, 2011, 397; Nutr Rev 71, 2013, S88; Placenta, 36, 2015, S20). Pathological placenta examination may reveal macroscopic and microscopic patterns that provide valuable information to the obstetricians, neonatologists, and pediatricians caring for the family. The placenta often plays a key role in understanding adverse fetal outcomes such as hypoxic brain injury, cerebral palsy, fetal growth restriction, stillbirth, and neonatal death (Placenta, 35, 2014, 552; Placenta, 52, 2017, 58; Placenta, 30, 2009, 700; Obstet Gynecol, 114, 2009, 809; Clin Perinatol, 33, 2006, 503; Pediatr Dev Pathol, 11, 2008, 456; Arch Pathol Lab Med, 124, 2000, 1785). Moreover, it may help to understand the pathophysiology of pregnancy, improve management of subsequent pregnancies, and assist in medicolegal assessment. Placental pathologic examination may even provide evidence of susceptibility to adult-onset diseases such as diabetes (Pediatr Dev Pathol, 6, 2003, 54; Diabetes Metab, 36, 2010, 682; BJOG, 113, 2006, 1126; Int J Gynaecol Obstet, 104, 2009, S25; Zentralbl Gynakol, 97, 1975, 875). Pathologic examination of the placenta may thus be of tremendous value, particularly for those women experiencing an adverse pregnancy outcome. However, this potential utility may be entirely wasted, if the findings are not communicated in an effective manner to the appropriate clinicians. An optimized, readily understandable report of pathological findings is essential for clinical utility.

Follow-up and management of recurrent pregnancy losses due to massive perivillous fibrinoid deposition

Massive perivillous fibrinoid deposition is a rare placental pathology associated with significant adverse pregnancy outcome and can recur. We provide a detailed case review of a woman through 10 of her pregnancies, including 8 consecutive pregnancy losses and 2 live births. We also conducted a retrospective chart review of all massive perivillous fibrinoid deposition placenta specimens at our institution over an eight-year period. A total of 42 cases of massive perivillous fibrinoid deposition were identified from 2007 to 2015, yielding an incidence of 0.16%. Recurrence was seen in subsequent pregnancy in eight out of nine (88.9%) cases with more than one specimen. The clinical characteristics, perinatal outcomes and α-feto protein level of the 42 cases are presented. Also, presented is a review of the literature discussing placental pathology, pathogenetic mechanisms and management of this condition.

Explaining Fetal Death--What Are the Contributions of Fetal Autopsy and Placenta Examination?

The aim of our study was to categorize fetal deaths by different diagnostic groups and see to what extent an autopsy of a presumably normal fetus contributes to the final diagnosis and how many unexplained fetal deaths remain unexplained after examination of the placenta. We reviewed autopsy reports of 351 fetuses with a gestational age of 12 or more weeks at the Department of Pathology and Medical Genetics at St Olavs Hospital during the years 2001 through 2010. In our records, 38.5% (135 of 351) of the deaths were due to noninfectious placenta causes, 31.6% (111 of 351) were caused by infections, and 29.9% (105 of 351) of the fetal deaths remained unexplained after autopsy. We also found that an inconclusive report was more common early in pregnancy. The incidence of fetal loss due to circulatory disturbances in the placenta increased toward term. Infections were evenly distributed in intrauterine fetal deaths, although in spontaneous abortions, they were more frequent during the second trimester. For both explained and unexplained deaths, we observed a bimodal distribution, with peaks in the early second trimester and late third trimester toward term.

Placental histology in clinically unexpected severe fetal acidemia at term

BACKGROUND

Fetal acidemia at birth is defined as a newborn condition wherein the cord blood pH value is less than 7.0. It could represent an association with newborn brain damage; therefore, it is important to investigate which conditions precipitate its occurrence. No extensive placental analysis has been performed in cases of acidotic newborns delivered from low-risk pregnancies.

AIMS

To study placental characteristics in cases with severe fetal acidemia.

STUDY DESIGN

Retrospective case-control study.

SUBJECT

34 cases, 102 controls.

OUTCOME MEASURES

Umbilical artery pH was measured at delivery from a doubly clamped portion of the cord. Placental characteristics were compared between cases with severe fetal acidemia (cord pH at birth <7.0) and controls (normal pH at birth) in term low-risk pregnancies.

RESULTS

Macroscopic placental and umbilical cord characteristics were comparable in cases and controls whereas histological characteristics exhibited differences: diffuse villous edema, increased number of syncytial knots and villous branching abnormalities significantly affected cases more frequently than controls. Diffuse villous edema is related to fetal vascularization and associated with an increase of venous pressure; in our low-risk population, it is conceivable that these changes of fetal flow and pressure occurred in labor during the alteration of fetal heart rate. An increased number of syncytial knots and villous branching abnormalities have been previously associated with chronic placental hypoxic condition; in our low-risk population they could reflect a clinically undetectable hypoxic situation that acted during pregnancy reducing fetal resources to bear labor and delivery.

CONCLUSIONS

Placental histology provides useful information related to fetal acidemia in low-risk term pregnancy.

Obstetrical and neonatal outcomes among women infected with hepatitis C and their infants

OBJECTIVES

(1) To describe obstetrical and neonatal outcomes among a cohort of hepatitis C virus (HCV) infected women, comparing HCV RNA positive to HCV RNA negative women; (2) to characterize virologic and hepatic parameters associated with HCV infection during pregnancy; and (3) to describe the rate of HCV vertical transmission.

METHODS

We prospectively enrolled 145 HCV-positive pregnant women across British Columbia between 2000 and 2003. Participating women were monitored during pregnancy and their infants were followed to assess them for HCV infection. Maternal HCV RNA was assessed close to delivery.

RESULTS

Seventy percent of women reported injection drug use as their primary risk factor for HCV acquisition. Observed rates of intrauterine fetal death, preterm delivery, small for gestational age, and low birth weight infants were 3.4%, 17.9%, 11.3%, and 12.5%, respectively, without a significant association with maternal HCV RNA status. The rate of cholestasis was 5.6% in the HCV RNA-positive group (6/108) and 2.8% in the HCV RNA-negative group (1/37) (P = 0.496). Serum alanine aminotransferase levels decreased significantly through pregnancy, and were significantly higher in HCV RNA-positive women than in HCV RNA-negative women after controlling for cholestasis, co-infections, and alcohol consumption. Among the HCV RNA-positive women, the median FIB-4 score was 0.67 (IQR 0.56 to 0.76) in the first trimester, 0.74 (IQR 0.52 to 1.18) in the second trimester, and 0.89 (IQR 0.52 to 1.09) in the third trimester (P = 0.02). The median HCV viral load at delivery was 424 561 IU/mL. The vertical transmission rate was 4.7% in HCV RNA-positive women, with no cases in HCV RNA-negative women.

CONCLUSION

Because of the high rates of poor obstetrical outcomes found in this prospective cohort, population-level screening for HCV in pregnancy should be considered.

A pathologist׳s perspective on the perinatal autopsy

The perinatal autopsy is an important tool in the investigation of fetal and neonatal death, and a complete understanding of its risks and benefits is necessary for providers of perinatal care. This review, from the perspective of a perinatal pathologist, reports the details of the autopsy procedure, its goals, its value to individual patients and the health care system in general, and its alternatives. Even with new emerging technologies, the conventional perinatal autopsy remains the gold standard for determining the cause of death and the final summary of all pathologic findings. Therefore, the information provided in this review can help providers properly convey information about perinatal autopsy to bereaved families.

Viral infection in placenta relevant cells--a morphological and immunohistochemical cell culture study

Viral infections in pregnancy are known to cause fetal malformation, growth restriction, and even fetal death. Macroscopic placental examination usually shows slight and unspecific changes. Histology may show secondary, non-specific tissue reaction, i.e. villitis with lymphocytic invasion. Primary specific morphology characteristics are known for some virus, like cytomegalovirus, parvovirus, and herpes simplex, however many viral infections show non-specific changes. Placenta relevant cells as human first trimester trophoblasts HTR8/SVneo, primary human umbilical vein endothelial cells (HUVEC), and primary human embryonic fibroblasts were examined following infection with commonly occurring virus like adenovirus and enterovirus. Morphology in routine stained sections and virus-specific immunostains were studied 4, 8, 24, 48, 72 h after infection. Nuclear enlargement was seen in the infected cells. A specific diagnosis of adenovirus or enterovirus infection, however, was not possible without specific immunostains.

Clinical dilemma of positive histologic chorioamnionitis in term newborn

BACKGROUND

Although histologic chorioamnionitis (HCA) is known to be associated with poor outcomes in preterm infants, its clinical significance among term infants is not clearly known.

OBJECTIVES

To investigate the utility of HCA in determining early onset clinical sepsis (EOCS) among term newborns.

METHODS

The incidence of HCA and EOCS in term infants born during 2008-2009 was evaluated in a single center retrospective study (n = 3417). The predictive value of HCA for determining EOCS in term infants admitted to the neonatal intensive care unit (NICU) for suspected sepsis (n = 388) was quantified. Outcome of otherwise healthy term infants in the nursery with HCA was also investigated.

RESULTS

Overall, 11% of term infants with HCA also had EOCS. HCA was associated with increased risk for EOCS (OR 2.6, 95% confidence interval 1.6-4.2, P < 0.001) among term infants admitted to the NICU for suspected sepsis. No cases of EOCS were found among otherwise well-appearing infants in the nursery with HCA. Multiple logistic regression analysis indicated that addition of HCA does not increase the power of a model combining C-reactive protein (CRP) and immature to total neutrophil ratio in determining EOCS.

CONCLUSION

Although HCA in term infants is associated with EOCS, it did not improve the ability of CRP and immature to total neutrophil ratio to predict EOCS. Routine placental examination may not contribute to the diagnosis of EOCS in term infants.

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.

A new, clinically oriented, unifying and simple placental classification system

OBJECTIVE

At present there is no internationally accepted, clinically easy understandable, comprehensive morphological placental classification. This hampers international benchmarking and comparisons, and clinical research.

STUDY DESIGN

Internationally published criteria on morphological placental pathology were collected, standardized and focused into a comprehensive diagnosis category system. The idea was to create a clinically relevant placental pathology scheme related to major pathological processes. A system of nine main diagnostic categories (normal placenta included) was constructed. Pathologists and obstetricians discussed the mutual understanding of the wording in the reporting. The previously published diagnostic criteria were merged, structured and standardized. Through an interobserver correlation study on 315 placentas from intrauterine deaths and 31 controls (placentas from live births) the microscopic criteria in this classification system were tested on user-friendliness and reproducibility.

RESULTS

The clinical feedback has been very positive, focusing on the understandability and usefulness in patient follow-up. The interobserver agreement in the microscopic correlation study was in general good. The differences in agreement mainly reflected the degree of preciseness of the microscopic criteria, exemplified by excellent correlation in diagnosing acute chorioamnionitis. Maternal and fetal circulatory disorders need grading criteria and studies are needed to get more insight and clinical correlations of villitis and maturation disorders.

CONCLUSION

The clinically oriented, unifying and simple placental pathology classification system may work as a platform for standardization and international benchmarking. Further research is needed to define diagnostic criteria in staging and grading of some main diagnostic categories.

How important is placental examination in cases of perinatal deaths?

Research on stillbirths and placental pathology has traditionally been given low priority, causing a lack of understanding of the mechanisms leading to death. The purpose of this study was to gain knowledge on how many perinatal deaths relate to morphologic changes in the placenta, and what role the placenta plays in the pathogenesis of intrauterine, intrapartum, and neonatal deaths. The autopsy reports from 104 consecutive perinatal deaths in a 5-year period (2004-2008) were reviewed. Intrauterine, intrapartum, and neonatal deaths ranging from gestational age of 22 weeks up to 7 days postpartum were included. The following three questions were considered: Could placental examination (with autopsy) explain fetal/infant death; could the cause of death be explained by placental examination alone; and could the cause of death be explained with autopsy alone? The distribution of pathologic findings in the placenta was registered. The placenta had changes that could explain fetal/infant death in 69.2% of the cases. The cause of death could be explained by placental examination alone, without autopsy, in 48.1% of the cases. Only 16.3% of the deaths could be explained by autopsy alone. The most frequently observed diagnoses were infection (22.1%), degenerative changes (13.5%), and abruptio placentae (12.5%). To conclude, our study shows that placental examination in addition to autopsy is necessary in investigating the causes of perinatal deaths. Further research, including maternal and environmental factors, is needed to clarify the underlying causes of placental malfunction.

Ultrasound of the placenta: a systematic approach. Part I: Imaging

Diagnostic ultrasound has been in use in clinical obstetrics for close to half-a-century. However, in the literature, examination of the placenta appears to be treated with less attention than the fetus or the pregnant uterus. This is somewhat unexpected, given the obvious major functions this organ performs during the entire pregnancy. Examination of the placenta plays a foremost role in the assessment of normal and abnormal pregnancies. A methodical sonographic evaluation of the placenta should include: location, visual estimation of the size (and, if appearing abnormal, measurement of thickness and/or volume), implantation, morphology, anatomy, as well as a search for anomalies, such as additional lobes and tumors. Additional assessment for multiple gestations consists of examining the intervening membranes (if present). The current review considers the various placental characteristics, as they can be evaluated by ultrasound, and the clinical significance of abnormalities of these features. Numerous and varied pathologies of the placenta can be detected by routine ultrasound. It is incumbent on the clinician performing obstetrical ultrasound to examine the placenta in details and in a methodical fashion because of the far reaching clinical significance and potentially avoidable severe consequences of many of these abnormalities.

Placental histopathologic features in patients with thrombophilic mutations

The purpose of this article is to review the histopathologic findings in the placenta of women with a known thrombophilic mutation. The findings range from normal to severe pathologic features including decidual vasculopathy, placental infarctions, syncytial knotting, maternal floor infarction, fetal thrombotic vasculopathy, vasculitis, and chronic villitis. They are, however, not pathognomonic of thrombophilic states, nor are necessarily markers of perinatal damage. The prospective evaluation of cases with known thrombophilic mutations and the application of tissue microarray examination of the placenta may allow identification of major histopathologic features and molecular parameters associated with maternal and/or fetal thrombophilic states. This may assist clinicians in their consultation with patients and optimize management in future pregnancies.