Placental infarction and toxemia of pregnancy

Placental infarcts in the collaborative perinatal project: Variable associations infer variable constructs

PURPOSE

Reproducible diagnoses of placental infarcts may permit more accurate assessment of their clinical significance. Using data across the 12 study sites of the National Collaborative Perinatal Project, we investigated the consistency of associations between infarct features with birthweight, placental weight and measures of placental "efficiency."

METHODS

All delivered infants, live or stillborn, single or multiple, regardless of gestational age, were included. Pathologists scored infarcts by color (tan-white or "old" or pink-red "more recent"), size (cm), location (marginal or central), and total number.

RESULTS

Incidence of any infarcts and distributions of specific features such as size, color (indicating age), locations and total numbers of infarcts were highly variable across sites, as were their associations with birthweight and placental efficiency. The most stable associations (consistent results across sites) of placental infarct scores were with placental size and/or other placental shape variables and with birthweight, but the number of significant associations ranged from 13 to 1.

CONCLUSION

Given the extremes of infarct incidence within each site plus the variable correlations of infarct features with other placental and birth outcome measures, CPP infarct scores cannot be used as indicative of an underlying shared pathophysiologic construct. However, given the accumulating evidence that intrauterine stressors have the potential for lifelong impact on health, we propose that the infarct features and distinctions proposed are neither complex nor should they be jettisoned. Rather these measures should be clarified and refined. Only then can we understand the reported associations of placental infarcts with child and adult health outcomes.

Foetal autopsy-categories and causes of death

INTRODUCTION

Intrauterine death(IUD)/ Stillbirth forms a major part of perinatal mortality which thereby is a good indicator of pregnancy wastage as well as quality of healthcare available. The key objectives of autopsy examination are to know the cause(s) of death, elucidation of pathogenic mechanism and quality control of clinical management. The aim of this study was to identify the prevalent causes of IUD, thereby taking appropriate measures to prevent them and decrease the perinatal mortality rate.

MATERIALS AND METHODS

The study included 14 cases of IUD received for autopsy in the Department of Pathology over a period of five years. Autopsies were performed as per standard protocol and included full anthropometric profile, external examination, gross and microscopic evaluation of different organs and placenta.

RESULTS

Total number of 14 fetal autopsies were performed over a period of 5 years. The causes were broadly classified as fetal, maternal and placental. Placental causes were seen in majority of cases (48.57%) followed by fetal (35.72%) and then maternal (21.42). Most prevalent cause of death was congenital anomalies (28.6%) followed by placental insufficiency (21.4%) and chorioamnionitis (14.2%).

CONCLUSION

Determination of causes of fetal death would prove beneficial to the clinicians and parents for better management and care in future pregnancies as well as in genetic counseling.

Types of maternal hypertensive disease and their association with pathologic lesions and clinical factors

Hypertensive disease (HD) during pregnancy includes chronic hypertension (HTN), gestational hypertension (GH), and preeclampsia/eclampsia (PEC). Differences between types of HD have not been well studied. Clinicopathologic features were compared between the HD groups and controls. HD was associated with lower Apgar scores, intrauterine growth restriction, IUGR, and delivery at an earlier gestational age (GA). IUGR was less common in the GH group, gestational age was lowest in the PEC. As expected, HD is associated with placental lesions of malperfusion, younger GA, and increased incidence of IUGR and controls showed less chronic and more "acute" lesions (ACA, MEC). Finally, comparisons of the HD groups showed differences only in GA and IUGR in the GH group as compared to the HTN and PEC groups. This suggests that GH may be associated with less severe clinical disease while showing similar pathologic features.

Placental lesions associated with maternal underperfusion are more frequent in early-onset than in late-onset preeclampsia

OBJECTIVE

Preeclampsia (PE) has been classified into early- and late-onset disease. These two phenotypic variants of PE have been proposed to have a different pathophysiology. However, the gestational age cut-off to define "early" vs. "late" PE has varied among studies. The objective of this investigation was to determine the prevalence of lesions consistent with maternal underperfusion of the placenta in patients with PE as a function of gestational age.

STUDY DESIGN

A nested case-control study of 8307 singleton pregnant women who deliver after 20 weeks of gestation was constructed based on a cohort. Cases were defined as those with PE (n=910); controls were pregnant women who did not have a hypertensive disorder in pregnancy (n=7397). The frequency of maternal underperfusion of the placenta (according to the criteria of the Society for Pediatric Pathology) was compared between the two groups. Logistic regression was used for analysis. Estimated relative risks (RRs) were calculated from odds ratios.

RESULTS

1) The prevalence of lesions consistent with maternal underperfusion was higher in patients with PE than in the control group [43.3% vs. 15.9%, unadjusted odds ratio 4.0 (95% CI 3.5-4.7); P<0.001]; 2) the estimated RR of maternal underperfusion lesions in PE was higher than in the control group [RR=2.8 (95% CI 2.5-3.0)]; 3) the lower the gestational age at delivery, the higher the RR for these lesions; 4) early-onset PE, regardless of the gestational age used to define it (<32, 33, 34, 35 or 37 weeks) had a significantly higher frequency of placental lesions consistent with maternal underperfusion than late-onset PE (P<0.001 for all).

CONCLUSIONS

1) The earlier the gestational age of preeclampsia at delivery, the higher the frequency of placental lesions consistent with maternal underperfusion; 2) our data suggest that demonstrable placental involvement as determined by pathologic examination differs in early- and late-onset preeclampsia; and 3) this phenomenon appears to be a continuum, and we could not identify a clear and unambiguous gestational age at which lesions consistent with underperfusion would not be present.

Complexity and complicity in eclampsia: barriers or bridges?

The aetiology of pre-eclampsia-eclampsia remains largely unclarified, despite over 100 years of systematic study. The assumption that the triggering event is linear and amenable to reductionist techniques has characterized these efforts. The main purpose of this paper is to show that complexity and complicity characterize most pathophysiological processes in pre-eclampsia-eclampsia, a situation suggesting that similar mechanisms must exist at the origin of the disease. The unique configuration of the intervillous space and the intensity of energy transference through the fetomaternal interface offer many dysfunctional possibilities, even in clinically normal pregnancies. The most characteristic seem to be: the shedding and deportation of trophoblast, the fragmentation of villi, the escape of fetal blood, and events associated with trophoblast damage, degeneration and death. The pathogenic potential of these natural processes seems to depend on the association with amplifiers and permissive factors, which vary from person to person and from time to time. Thus, considering the convergence of multiple factors and the presence of nonlinearity in some of their interactions as a plausible working hypothesis, further exploration on this subject should adhere to the rules of this different reality. To find the best possible method of inquiry and to recognize its limitations will be the surest way to avoid failure.

Placental thrombi and other vascular lesions. Classification, morphology, and clinical correlations

Vascular lesions, most often mediated by thrombi, are second only to infections as a cause of fetal injury in the later weeks of pregnancy. In our experience many pathologists who examine placentas fail to conduct a proper search for vascular lesions and some even fail to recognize those exposed by their examination. This review is intended to define the typical clinical background or circumstances that suggest the presence of significant vascular problems, to define techniques calculated to display them well, and to identify criteria for diagnosis. Further research is needed to evaluate the prevalence of maternal and fetal hypercoagulable states and thrombi as a cause of fetal injury.

Fibrinolysis in pre-eclamptic toxaemia of pregnancy

Plasma fibrinolysis is much reduced in normal pregnancy but is the same in women with toxaemia or hypertension, though urinary fibrinolysis is lower in them. The evidence suggests that in toxaemia there must be in addition a slow state of intravascular coagulation. Fibrinolytic inhibitors were found to be normal in this series, though in pregnancy there are raised levels of antitrypsin, alpha(2)-macroglobulin, and beta-lipoprotein. beta-Lipoprotein levels in non-pregnant patients show a correlation with euglobulin lysis times and with inhibitor units.