Stillbirth due to SARS-CoV-2 placentitis without evidence of intrauterine transmission to fetus: association with maternal risk factors

OBJECTIVES

To describe the placental pathology, fetal autopsy findings and clinical characteristics of pregnancies that resulted in stillbirth owing to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) placentitis, and to identify potential risk factors.

METHODS

This was a prospective multicenter study of non-vaccinated pregnant women affected by coronavirus disease 2019 (COVID-19) in Greece from April 2020 to August 2021. A total of 165 placentas were examined histologically and six cases of stillbirth associated with SARS-CoV-2 placentitis were retrieved. Complete fetal autopsy was performed in three of these cases. Gross, histopathological, immunohistochemical, molecular and electron microscopy examinations were carried out in the stillbirth placentas and fetal organs. The histological findings of cases with SARS-CoV-2 placentitis were compared with those in 159 cases with maternal COVID-19 which resulted in a live birth. Regression analysis was used to identify predisposing risk factors for SARS-CoV-2 placentitis.

RESULTS

The placentas of all six stillborn cases showed severe and extensive histological changes typical of SARS-CoV-2 placentitis, characterized by a combination of marked intervillositis with a mixed inflammatory infiltrate and massive perivillous fibrinoid deposition with trophoblast damage, associated with intensely positive immunostaining for SARS-CoV-2 spike protein, the presence of virions on electron microscopy and positive reverse-transcription polymerase chain reaction test of placental tissues. The histological lesions obliterated over 75% of the maternal intervillous space, accounting for intrauterine fetal death. Similar histological lesions affecting less than 25% of the placenta were observed in seven liveborn neonates, while the remaining 152 placentas of COVID-19-affected pregnancies with a live birth did not show these findings. Complete fetal autopsy showed evidence of an asphyctic mode of death without evidence of viral transmission to the fetus. The mothers had mild clinical symptoms or were asymptomatic, and the interval between maternal COVID-19 diagnosis and fetal death ranged from 3 to 15 days. Statistically significant predisposing factors for SARS-CoV-2 placentitis included thrombophilia and prenatally diagnosed fetal growth restriction (FGR). Multiple sclerosis was seen in one case.

CONCLUSIONS

SARS-CoV-2 placentitis occurred uncommonly in COVID-19-affected pregnancies of non-vaccinated mothers and, when extensive, caused fetal demise, with no evidence of transplacental fetal infection. Thrombophilia and prenatally detected FGR emerged as independent predisposing factors for the potentially lethal SARS-CoV-2 placentitis. © 2022 International Society of Ultrasound in Obstetrics and Gynecology.

Premature ovarian insufficiency: a toolkit for the primary care physician

Premature ovarian insufficiency (POI) refers to the loss of ovarian activity before the age of 40 years, which leads to hypoestrogenism and amenorrhea. The diagnosis of POI in a young woman has potentially life-changing physical and emotional consequences for both the patient and her family. Therefore, it is very important that the diagnosis is correct and that it is made in a timely manner. Unfortunately, the diagnosis and therefore the effective treatment of POI are often delayed, which underlines the need for education of the broad medical community on the issue. A panel of menopause experts reviewed and critically appraised the literature, and present: (1) the diagnostic approach to POI, (2) the investigation of the etiology of this condition, (3) the therapeutic strategy regarding both hormone replacement therapy and fertility, and (4) the long-term follow-up and management for ensuring quality of life, as well as urogenital, cardiovascular, bone and mental health. The ultimate goal of this article is to provide a complete toolkit for the primary care physician to have easy access to all the information needed for the optimal management of women with POI, in the context of evidence-based and personalized medicine.HIGHLIGHTSPremature ovarian insufficiency occurs in 1% of the female population of reproductive age, yet the diagnosis is often delayed, with severe physical and emotional consequences for the patient.Primary care physicians should be aware of the possibility of premature ovarian insufficiency in young women presenting with menstrual irregularity.Prompt initiation of hormone replacement therapy ensures quality of life and prevents osteoporosis and cardiovascular disease.Women seeking fertility should be referred to specialists to discuss assisted reproduction options.

Aberrant expression of corticotropin-releasing hormone in pre-eclampsia induces expression of FasL in maternal macrophages and extravillous trophoblast apoptosis

Corticotropin-releasing hormone (CRH) and its receptors are expressed in human placenta. Recently, the impaired function of this system has been associated with a number of complications of pregnancy, including pre-eclampsia. The aim of the study was to test the hypothesis that CRH participates in the pathophysiology of pre-eclampsia through the induction of macrophage-mediated apoptosis of extravillous trophoblasts (EVTs). We found that the expression of CRH was increased in the EVT of the placental bed biopsy specimens from pre-eclamptic pregnancies (1.8-fold increase; P < 0.05). In addition, significantly larger numbers of apoptotic EVT were detected in pre-eclamptic placentas compared with normal ones (P < 0.05), and only in pre-eclamptic placentas, decidual macrophages were found to be Fas ligand (FasL)-positive. In vitro studies on the effect of CRH on human macrophages suggested that CRH induced the expression of the FasL protein in human macrophages and potentiated their ability to induce the apoptosis of a Fas-expressing EVT-based hybridoma cell line in co-cultures. These findings demonstrate a possible mechanism by which the aberrant expression of CRH in pre-eclampsia may activate the FasL-positive decidual macrophages, impair the physiological turnover of EVT and eventually disturb placentation.

Endometrial and placental CRH as regulators of human embryo implantation

Epithelial cells of the human endometrium and differentiated endometrial stromal cells express the corticotropin-releasing hormone (CRH) gene. CRH is also produced by human placental cytotrophoblast. Endometrial and placental CRH are under the endocrine control of gonadal steroids as well as under autocrine/paracrine regulation by prostanoids and interleukins. Human endometrium, myometrium and placenta express the relevant receptors. Human trophoblast and decidualized endometrial cells also express Fas ligand (FasL), a pro-apoptotic molecule. These findings suggest that intra-uterine CRH may participate in local inflammatory phenomena associated with blastocyst implantation, while FasL may assist with maternal immune tolerance to the semi-allograft embryo. A nonpeptidic CRH receptor type 1 (CRH-R1)-specific antagonist decreased the expression of FasL by human trophoblasts, suggesting that CRH regulates the pro-apoptotic potential of these cells in an auto-paracrine fashion. Invasive trophoblasts promoted apoptosis of activated Fas-expressing human T lymphocytes, an effect potentiated by CRH and inhibited by the CRH antagonist. Female rats treated with the CRH antagonist in the first 6 days of gestation had a dose-dependent decrease of endometrial implantation sites and live embryos as well as markedly diminished endometrial FasL expression. However, embryos of mothers lacking T cells (nude rats) and embryos of syngeneic matings were not rejected when mothers were treated with antalarmin, suggesting that the effect of antalarmin on embryonic implantation is not due to a nonspecific toxicity of this compound but a specific effect on T cells. Our data suggest important physiological roles of endometrial and placental CRH in the regulation of blastocyst implantation and early maternal tolerance.

Participation of Maternal and Fetal CRH in Early Phases of Human Implantation: The Role of Antalarmin

The hypothalamic neuropeptide corticotropin-releasing hormone (CRH) is produced by several tissues of the female reproductive system. It is also secreted at inflammatory sites and possesses potent pro-inflammatory properties influencing both innate and acquired immune processes. Uterine CRH participates in local immune early pregnancy phenomena, such as decidualization of endometrial strom a and protection of the fetus from maternal immune system. This is maintained through induction of the expression of apoptotic FasL on invasive extravillous trophoblast and maternal decidual cells at the fetal-maternal interface. Furthermore, CRH increases apoptosis of activated T lymphocytes through FasL induction participating in the process of implantation and early pregnancy. Female rats treated with the non-peptidic CRH receptor 1 (CRHR1) specific antagonist antalarmin, in the first 6 days of gestation, have undergone a decrease of endometrial implantation sites and live embryos and markedly diminished endometrial FasL expression.

Corticotropin-releasing hormone promotes blastocyst implantation and early maternal tolerance

The semi-allograft embryo in the blastocyst stage implants itself in the endometrium, yet no immune rejection processes are activated. Embryonic trophoblast and maternal decidua produce corticotropin-releasing hormone (CRH) and express Fas ligand (FasL), a proapoptotic cytokine. We found that antalarmin, a CRH receptor type 1 antagonist, decreased FasL expression and promoted apoptosis of activated T lymphocytes, an effect which was potentiated by CRH and inhibited by antalarmin. Female rats treated with antalarmin showed a marked decrease in implantation sites and live embryos and diminished endometrial FasL expression. Embryos from mothers that lacked T cells or from syngeneic matings were not rejected when the mothers were given antalarmin. These findings suggested that locally produced CRH promotes implantation and maintenance of early pregnancy primarily by killing activated T cells.