A pilot study of the frequency and significance of placental villitis

Placental pathology in spontaneous and iatrogenic preterm birth: Different entities with unique pathologic features

INTRODUCTION

Placental pathology is an important contributor to the understanding of preterm birth and reveals major differences between spontaneous preterm birth (SPTB) and iatrogenic preterm birth (IPTB). The aim of this study was to investigate these relationships.

METHODS

Research midwives collected placentas from 1101 women with singleton pregnancies who were enrolled in the Safe Passage Study. Trained pathology technologists prepared and processed placenta specimens for macroscopic and microscopic examination by designated pathologists. Statistical analyses were done with STATISTICA version 13.

RESULTS

In SPTB we found more cases of accelerated villous maturation; however, the other features of maternal vascular malperfusion (MVM) were not present. The prevalence rate of funisitis was also increased. In IPTB, multiple features of MVM - accelerated villous maturation, distal villous hypoplasia, decidual arteriopathy, increased syncytial knots, increased perivillous fibrin, and prominent extravillous trophoblast were increased, as were features of fetal vascular malperfusion (FVM) - umbilical cord vessel thrombosis, avascular villi, and fetal vascular thrombosis. Increased syncytial knots were found in 26% of preterm stillbirths and in 29% of preterm infant demises as compared to 81% of IPTB infants alive at one year.

DISCUSSION

SPTB and IPTB differ. The detected "abnormal" accelerated villous maturation pattern in SPTB and preterm demises, suggests an inability of the placenta to adapt and may be a trigger for SPTB. Funisitis was the only inflammatory response significant for SPTB. MVM and FVM are implicated in IPTB, but not an inflammatory process.

Chronic villitis in untreated neonatal alloimmune thrombocytopenia: an etiology for severe early intrauterine growth restriction and the effect of intravenous immunoglobulin therapy

OBJECTIVE

The objective of the study was to examine placental histopathology in intravenous immunoglobulin-treated and untreated neonatal alloimmune thrombocytopenia and correlate pathological findings with clinical outcomes.

STUDY DESIGN

Placentas from 14 neonatal alloimmune thrombocytopenia-affected pregnancies were identified. Maternal antepartum treatment with intravenous immunoglobulin and pregnancy outcomes were abstracted from medical records. Placental histopathology and clinical outcomes were compared between intravenous immunoglobulin and no intravenous immunoglobulin treatment groups using Fisher's exact test. One subject, treated only after an intracranial hemorrhage (ICH) was diagnosed, was excluded from the analysis. P < .05 was considered significant.

RESULTS

Untreated pregnancies demonstrated a lymphoplasmacytic chronic villitis not seen in the intravenous immunoglobulin-treated pregnancies (P = .005). Intrauterine growth restriction and intrauterine fetal demise occurred as frequently as ICH in the untreated group. No ICH, intrauterine growth restriction, or intrauterine fetal demises occurred in the treated group, although the P value was not significant.

CONCLUSION

Chronic villitis is frequently manifest in neonatal alloimmune thrombocytopenia, with intravenous immunoglobulin alleviating this inflammatory immunologic response. We suspect a more universal role for the maternal antibody, such as fetal endothelial cell damage, in the sequelae of neonatal alloimmune thrombocytopenia.

Chronic chorioamnionitis: a clinicopathologic and immunohistochemical study

Lymphocytic inflammation of the fetal membranes is unusual and has been termed chronic chorioamnionitis. We report the clinicopathologic and immunohistochemical findings in 31 placentas with chronic chorioamnionitis. The most common histopathologic association was chronic villitis of unknown etiology, which was identified in 22 (71%) of the 31 placentas. The severity of the chronic villitis did not correlate with the severity of chronic chorioamnionitis. Additional placental findings included chronic intervillositis in two, fetal vessel thrombosis in five, hemorrhagic endovasculitis in four, decidual chronic vasculitis in three, and atherosis in one. Maternal history included pregnancy-induced hypertension in six and diabetes in one. Twelve infants were preterm, and five had intrauterine growth retardation. There was no neonatal sepsis or death. Immunohistochemical staining in areas of chronic chorioamnionitis showed CD3+ and CD8+ cells present in moderate numbers, and CD4+ cells in smaller numbers. CD20+ and CD56+ cells were rare or absent. Chronic chorioamnionitis is commonly associated with chronic villitis of unknown etiology, shares similar clinical associations, and may have a related cause, possibly immunologic.

Detection of the human cytomegalovirus gene in placental chronic villitis by polymerase chain reaction

Placental chronic villitis was observed in 44 cases (2.12%) of 2,073 histologically examined placentas. Infiltrating lymphocytes in chronic villitis were determined by immunohistochemistry to be predominantly helper/inducer T cells. Detection of the cytomegalovirus (CMV) gene was performed on paraffin-embedded sections by polymerase chain reaction (PCR) using two different primers (CMV immediate early gene and CMV late antigen gp 64). Both CMV immediate early gene and late antigen gp 64 gene were detected in one case. Cytomegalovirus late antigen gp 64 gene was observed in only three cases. Among these four cases, the cytomegalic inclusion body was observed only in a single case with light microscopic examination. In two cases generalized CMV infection was manifested during the early infantile period and the patient died of the disease. The other two cases were asymptomatic. Our data suggest that approximately 9% of the cases of chronic villitis are caused by CMV infection, and most of them are difficult to detect morphologically. Detection of CMV gene by PCR using primers, especially late antigen gp 64 gene, is very useful for assessing the cause of placental chronic villitis.

Chronic villitis of unknown etiology in twin gestations

Chronic villitis of unknown etiology (CVUE) is a frequently encountered placental lesion associated with poor pregnancy outcome. We examined 22 twin placentas with CVUE to determine its distribution and clinicopathological significance in twin gestations. CVUE affected both twins' placental portions with an approximately equal degree of severity in 12 of 22 cases (9 dichorionic, 3 monochorionic). Only one twin's placental portion was affected in 8 cases (8 dichorionic). In the remaining 2 (1 dichorionic, 1 monochorionic), both placental portions were affected, but the CVUE was significantly more severe in one. The CVUE varied in extent from rare foci to diffuse involvement. Seven of the 22 (32%) pairs of twins had intrapair weight differences of 15% or greater, and 14 pairs were premature. The twins with placental involvement by CVUE had a lower mean birthweight than their cotwins with less or no CVUE; however, these results were not statistically significant. CVUE may affect placentas from one or both twins, and may be a cause of discordant twin size.

Cytotoxic antibody against trophoblast and lymphocytes present in pregnancy with intrauterine fetal growth retardation and its relation to anti-phospholipid antibody

To elucidate immunological mechanisms involved in the genesis of intra-uterine fetal growth retardation (IUGR), an in vitro cytotoxicity assay against normal trophoblast and lymphocytes was performed. The data demonstrated the existence of cytotoxic antibody directed against trophoblast exclusively in the IgG fraction of the sera of 9 out of 15 mothers with IUGR, but in none of the sera from normal pregnant women. This antibody showed differential reactivity patterns that may be indicative women. This antibody showed differential reactivity patterns that may be trophoblast in common. Out of 9 IUGR mothers with this cytotoxic antibody, in 6 cases (66.7%) chronic villitis was evident upon microscopic examination of the placenta, the frequency being significantly higher than that in IUGR mothers without cytotoxicity or in control mothers (P less than 0.02). It is suggested that in situ inflammatory change triggered by this antibody might lead to IUGR through chronic villitis. This antibody showed cross-reactivity with anti-negatively charged phospholipid antibody, as confirmed by an absorption experiment, indicating that the trophoblast antigenic stimuli in pregnancy can induce the production of various autoantibodies including anti-phospholipid antibodies. These results are of interest in relation to the pathogenesis of autoimmune diseases.

C-reactive protein in preterm premature rupture of the membranes

The usefulness of maternal C-reactive protein (CRP) measurements in the diagnosis of chorioamnionitis and puerperal and neonatal infectious morbidity was studied among 147 patients with preterm rupture of the membranes (PROM). Thirty-three patients developed chorioamnionitis, 10 patients developed puerperal endometritis, and 21 newborn infants developed neonatal infections. There was no difference in the highest antepartum CRP between patients with or without chorioamnionitis. The overall test performance for CRP was poor suggesting that elevated antepartum CRP may be misleading in the diagnosis of chorioamnionitis. However, use of serial CRP measurements increases the test performance. The high negative predictive value suggests that CRP is useful in predicting the absence of chorioamnionitis.

Placental villitis and intrauterine growth retardation in a Swedish population

Villitis was studied in placentas from 445 singleton infants from an ethnically homogeneous population with a good socioeconomic standard. There were 161 infants small for gestational age (SGA) and 284 appropriate for gestational age (AGA). Villitis was found in 12 SGA-placentas (7.5 per cent) and 8 AGA placentas (2.8 per cent) (p less than 0.05). The degree of villitis was also related to growth retardation (p less than 0.05). Except for one placenta with villitis due to CMV infection, the cause of villitis could not be determined. No association was found with various studied factors such as hypertension, pre-eclampsia, smoking or maternal pyrexia during pregnancy.

Cord IgM levels in placentas with villitis of unknown etiology

Villitis of unknown etiology (VUE) is the largest category of the placental villitides and its incidence varies in different countries. The possibility that a higher incidence of intrauterine infection could explain the high frequency of VUE in developing countries led us to determine the incidence of raised IgM levels (a non-specific monitor to intrauterine infections) in cord serum of placentas with VUE. Eighty-six placentas were studied. Of these 67 were from infants with adequate weight for their gestational age (AGA) and 19 from infants small for their gestational age (SGA). IgM level in the cord serum was measured on radial immunodiffusion plates. VUE was found in 36 placentas (41.8%) and it predominated in the SGA group. Raised IgM levels were found in only 13.8% of the placentas with VUE. In spite of our frequency of VUE being high, our incidence of raised IgM levels in placentas with VUE was low and similar to that reported by authors who have low incidence of VUE in their series. We conclude that determination of cord IgM did not help significantly in the investigation of the cause of the high frequency of VUE in our series.

Fibrinoid and trophoblastic necrosis with massive chronic intervillositis: an extreme variant of villitis of unknown etiology

A placental lesion, characterized by fibrinoid and trophoblastic necrosis with massive infiltration of the intervillous space by mononuclear cells (massive chronic intervillositis, MCI), was observed in six cases, five with intrauterine growth retardation (IUGR) and one with sudden intrauterine fetal death. Four out of six had chronic villitis of unknown etiology (CVUE) associated with this lesion, and five had lesions of anchoring villitis. In three cases, acute atherosislike lesions in spiral arteries of parietal and/or basal decidua were observed. Massive deposits of IgM, a smaller amount of C3 and Clq, and slight deposits of IgG and IgA were found in these vessels. Neither mothers nor infants had any clinical or serological evidence of infection. Cases with MCI were compared with those having CVUE without intervillositis. Patients with MCI showed lower values of infant weight, infant length, and ponderal index than controls. However, cases with MCI group showed a higher incidence of IUGR. Placentas from the MCI group had a greater number of acute atherosislike lesions than controls. Massive chronic intervillositis may represent an extreme variant of villitis of unknown etiology. A maternal immunological aggression toward fetal tissues is proposed as pathophysiological mechanism, although a nondetermined placental infection cannot be excluded.

C-reactive protein: a limited test for managing patients with preterm labor or preterm rupture of membranes?

C-reactive protein has been used to identify patients at high risk for infectious morbidity with preterm labor or preterm rupture of membranes. In this article we report on 104 patients with preterm labor symptoms (n = 45) or preterm rupture of the membranes (n = 59) and serial evaluations of C-reactive protein measured by latex agglutination and laser nephelometry. The simple, inexpensive latex method appears comparable to the laser method in predicting infectious morbidity and can be used clinically. Elevated C-reactive protein values before delivery predict infectious morbidity in only 8% to 29% of patients, and up to 18% of patients with serious infections may be misdiagnosed as having normal C-reactive protein values before delivery.

Intrauterine growth retardation of unknown etiology: II. Serum complement and circulating immune complexes in maternal sera and their relationship with parity and chronic villitis

Significantly lower CH50 levels were found in women with small for gestational age (SGA) infants. The lowest values corresponded to nulliparous with placental chronic villitis (124.0 +/- 10.6). Three out of five mothers with circulating immune complexes from SGA group were nulliparous, having placental chronic villitis. An immunological derangement in women with SGA infants is proposed for the development of placental lesions, mainly in nulliparous mothers with a lower previous exposure to fetal antigens.