INFECTIONS IN PREGNANCY WITH COVID-19 AND OTHER RESPIRATORY RNA VIRUS DISEASES ARE RARELY, IF EVER, TRANSMITTED TO THE FETUS: EXPERIENCES WITH CORONAVIRUSES, HPIV, hMPV RSV, AND INFLUENZA

Possibility of intrauterine transmission from mother to fetus/newborn: Systematic review and meta-analysis of diagnostic methods to detect SARS-CoV-2 infection

Several studies have reported vertical transmission of SARS-CoV-2; however, information regarding intrauterine transmission based on diagnostic methods to detect SARS-CoV-2 infection is scarce. A systematic review and meta-analysis was conducted to identify and explore the studies that attempt to ascertain the possibility of intrauterine transmission of SARS-CoV-2 infection according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) statement. The results demonstrate that SARS-CoV-2 can be transmitted intrauterine, as detected by clinical manifestations (1.00, 95 % CI: 1.00 - 1.00, 0.51, 95 % CI: 0.22 - 0.80), imaging (0.50, 95 % CI: 0.24 - 0.76, 0.03, 95 % CI: 0.00 - 0.17), molecular (1. 00, 95 % CI: 1.00 - 1.00, 0.92, 95 % CI: 0.77 - 1.00), immunological (0.32, 95 % CI: 0.10 - 0.57, 0.34, 95 % CI: 0.11 - 0.61), and histological approaches (0.79, 95 % CI: 0.52 - 0.98) in maternal and fetal/neonatal specimens, respectively. The possibility of intrauterine transmission of SARS-CoV-2 from mother to fetus/newborn was 41 % (95 % CI 0.37 - 0.45). We might confirm/verify the intrauterine transmission of SARS-CoCV-2 from mother to fetus/newborn.

Histological and immunohistochemical features of the placenta associated with COVID-19: a systematic review and meta-analysis

OBJECTIVE

Aim: To make a systematic review and meta-analysis of published data on the study of histological and immunohistochemical features of the placenta in women who had acute coronavirus infection associated with SARS-CoV-2 ("Covid" placentas) during pregnancy.

PATIENTS AND METHODS

Materials and Methods: The search for literature data is based on the PRISMA methodology); the MEDLINE database (PubMed®) was searched using Medical Subject Headings terms from January 2020 to July 2023. The project was registered in the Open Sience Frame (Project Identifier: DOI 10.17605/OSF.IO/GDR3S, Registration DOI: https://doi.org/10.17605/OSF.IO/H2KPU). Preference was given to studies in which the description of placentas met the requirements of the Amsterdam Placental Workshop Group Consensus Statement.

RESULTS

Results: A total of 31 studies were included; the number of participants whose morphological and histological description of the placentas could be subjected to meta-analysis was 2401, respectively, in the group with a "Covid" history and 1910 - conditionally healthy pregnant women. Pathological changes in the placental complex were not detected in 42±19.62% of pregnant women with a history of Covid. Immunohistochemical examination of placentas preferably focuses on the detection of SARS-CoV-2 spike protein or ACE2. According to currently available studies, in the placentas of women who have had COVID-19 during pregnancy, there are no pathognomic histological patterns specific to this infection and direct damage to the placenta is rarely observed. Histological patterns in "covid" placentas are isolated, most often a combination of lesions in both the maternal and fetal malperfusion.

CONCLUSION

Conclusions: According to currently available studies, in the placentas of women who have had COVID-19 during pregnancy, there are no pathognomic histological patterns specific to this infection and direct damage to the placenta is rarely observed. The probability of infection of the intrauterine fetus by the transplacental hematogenous route is the lowest compared to other routes, which, in our opinion, is a possible explanation for the high frequency of MVM without subsequent infection of the fetus.

The protective role of maternal genetic immunization on maternal-fetal health and welfare

Pregnancy is a critical period associated with alterations in physiologic, biologic, and immunologic processes, which can affect maternal-fetal health through development of several infectious diseases. At birth, neonates have an immature immune system that makes them more susceptible to severe viral infections and diseases. For this reason, different maternal nutritional and immunization interventions have been used to improve the immune and health status of the mother and her neonate through passive immunity. Here, we reviewed the protective role of maternal immunization with different types of vaccines, especially genetic vaccines, during pregnancy in maternal-fetal health, immune response, colostrum quality, immune response, and anti-oxidative status. For this purpose, we have used different scientific databases (PubMed and Google Scholar) and other official web pages. We customized the search period range from the year 2000 to 2023 using the key words "maternal immunization" OR "gestation period/pregnancy" OR "genetic vaccination" OR "maternal-fetal health" OR "micronutrients" OR "neonatal immunity" "oxidative stress" OR "colostrum quality". The evidence demonstrated that inactivated or killed vaccines produced significant immune protection in the mother and fetus. Furthermore, most recent studies have suggested that the use of genetic vaccines (mRNA and DNA) during pregnancy is efficient at triggering the immune response in mother and neonate without the risk of undesired pregnancy outcomes. However, factors such as maternal redox balance, nutritional status, and the timing of immunization play essential roles in regulating immune response inflammatory status, antioxidant capacity, and the welfare of both the pregnant mother and her newborn.

Common pathways targeted by viral hemorrhagic fever viruses to infect the placenta and increase the risk of stillbirth

Viral hemorrhagic fevers (VHF) are endemic to Africa, South America and Asia and contribute to significant maternal and fetal morbidity and mortality. Viruses causing VHFs are typically zoonotic, spreading to humans through livestock, wildlife, or mosquito vectors. Some of the most lethal VHF viruses also impart a high-risk of stillbirth including ebolaviruses, Marburg virus (MARV), Lassa virus (LASV), and Rift Valley Fever Virus (RVFV). Large outbreaks and epidemics are common, though the impact on the mother, fetus and placenta is understudied from a public health, clinical and basic science perspective. Notably, these viruses utilize ubiquitous cellular surface entry receptors critical for normal placental function to enable viral invasion into multiple key cell types of the placenta and set the stage for maternal-fetal transmission and stillbirth. We employ insights from molecular virology and viral immunology to discuss how trophoblast expression of viral entry receptors for VHF viruses may increase the risk for viral transmission to the fetus and stillbirth. As the frequency of VHF outbreaks is expected to increase with worsening climate change, understanding the pathogenesis of VHF-related diseases in the placenta is paramount to predicting the impact of emerging viruses on the placenta and perinatal outcomes.

Mild/asymptomatic COVID-19 in unvaccinated pregnant mothers impairs neonatal immune responses

Maternal SARS-CoV-2 infection triggers placental inflammation and alters cord blood immune cell composition. However, most studies focus on outcomes of severe maternal infection. Therefore, we analyzed cord blood and chorionic villi from newborns of unvaccinated mothers who experienced mild/asymptomatic SARS-CoV-2 infection during pregnancy. We investigated immune cell rewiring using flow cytometry, single-cell RNA sequencing, and functional readouts using ex vivo stimulation with TLR agonists and pathogens. Maternal infection was associated with increased frequency of memory T and B cells and nonclassical monocytes in cord blood. Ex vivo T and B cell responses to stimulation were attenuated, suggesting a tolerogenic state. Maladaptive responses were also observed in cord blood monocytes, where antiviral responses were dampened but responses to bacterial TLRs were increased. Maternal infection was also associated with expansion and activation of placental Hofbauer cells, secreting elevated levels of myeloid cell-recruiting chemokines. Moreover, we reported increased activation of maternally derived monocytes/macrophages in the fetal placenta that were transcriptionally primed for antiviral responses. Our data indicate that even in the absence of vertical transmission or symptoms in the neonate, mild/asymptomatic maternal COVID-19 altered the transcriptional and functional state in fetal immune cells in circulation and in the placenta.

Maternal prenatal immune activation associated with brain tissue microstructure and metabolite concentrations in newborn infants

Importance

Few translational human studies have assessed the association of prenatal maternal immune activation with altered brain development and psychiatric risk in newborn offspring.

Objective

To identify the effects of maternal immune activation during the 2nd and 3rd trimesters of pregnancy on newborn brain metabolite concentrations, tissue microstructure, and longitudinal motor development.

Design

Prospective longitudinal cohort study conducted from 2012 - 2017.

Setting

Columbia University Irving Medical Center and Weill Cornell Medical College.

Participants

76 nulliparous pregnant women, aged 14 to 19 years, were recruited in their 2nd trimester, and their children were followed through 14 months of age.

Exposure

Maternal immune activation indexed by maternal interleukin-6 and C-reactive protein in the 2nd and 3rd trimesters of pregnancy.

Main Outcomes and Measures

The main outcomes included (1) newborn metabolite concentrations, measured as N-acetylaspartate, creatine, and choline using Magnetic Resonance Spectroscopy; (2) newborn fractional anisotropy and mean diffusivity measured using Diffusion Tensor Imaging; and (3) indices of motor development assessed prenatally and postnatally at ages 4- and 14-months.

Results

Maternal interleukin-6 and C-reactive protein levels in the 2nd or 3rd trimester were significantly positively associated with the N-acetylaspartate, creatine, and choline concentrations in the putamen, thalamus, insula, and anterior limb of the internal capsule. Maternal interleukin-6 was associated with fractional anisotropy in the putamen, insula, thalamus, precuneus, and caudate, and with mean diffusivity in the inferior parietal and middle temporal gyrus. C-reactive protein was associated with fractional anisotropy in the thalamus, insula, and putamen. Regional commonalities were found across imaging modalities, though the direction of the associations differed by immune marker. In addition, a significant positive association was observed between offspring motor development and both maternal interleukin-6 and C-reactive protein (in both trimesters) prenatally and 4- and 14-months of age.

Conclusions and Relevance

Using a healthy sample, these findings demonstrate that levels of maternal immune activation in mid- to late pregnancy associate with tissue characteristics in newborn brain regions primarily supporting motor integration/coordination and behavioral regulation and may lead to alterations in motor development.

Application of functional proteomics in understanding RNA virus-mediated infection

Together with the expansion of genome sequencing research, the number of protein sequences whose function is yet unknown is increasing dramatically. The primary goals of functional proteomics, a developing area of study in the realm of proteomic science, are the elucidation of the biological function of unidentified proteins and the molecular description of cellular systems at the molecular level. RNA viruses have emerged as the cause of several human infectious diseases with large morbidity and fatality rates. The introduction of high-throughput sequencing tools and genetic-based screening approaches over the last few decades has enabled researchers to find previously unknown and perplexing elements of RNA virus replication and pathogenesis on a scale never feasible before. Viruses, on the other hand, frequently disrupt cellular proteostasis, macromolecular complex architecture or stoichiometry, and post-translational changes to take over essential host activities. Because of these consequences, structural and global protein and proteoform monitoring is highly necessiated. Mass spectrometry (MS) has the potential to elucidate key details of virus-host interactions and speed up the identification of antiviral targets, giving precise data on the stoichiometry of cellular and viral protein complexes as well as mechanistic insights, has lately emerged as a key part of the RNA virus biology toolbox as a functional proteomics approach. Affinity-based techniques are primarily employed to identify interacting proteins in stable complexes in living organisms. A protein's biological role is strongly suggested by its relationship with other members of a certain protein complex that is involved in a particular process. With a particular emphasis on the most recent advancements in defining host responses and their translational implications to uncover novel tractable antiviral targets, this chapter provides insight on several functional proteomics techniques in RNA virus biology.

Can asymptomatic SARS-CoV-2 infection cause spontaneous abortion?

Aim: The probability of spontaneous abortion is known to increase (15%) in the pregnant women who develop symptomatic and even “Severe Acute Respiratory Syndrome (SARS)” due to maternal infections. It is known that the SARS-CoV-2 virus, one of these infectious agents, enters host cells by binding to angiotensin-converting enzyme 2 (ACE2). New literature data have shown the increased ACE2 receptor in the endometrium during the decidualization phase and the ability of SARS-CoV-2 to enter endometrial stromal cells through ACE2 proteins. This shows that the COVID-19 infection can cause many pathologies such as early pregnancy loss. The aim of this study is to investigate the effects of SARS-CoV-2 virus which are positive in the uterine samples on pregnancy loss. Material and Method: 13 women who had first trimester pregnancy loss were included in this cross-sectional study. None of these pregnant women had any known symptoms of SARS-CoV-2 infection. SARS-CoV-2 infection was screened in uterus and naso-oropharynx samples by real-time polymerase chain reaction (RT-PCR) test in these pregnant women. Women with positive RT-PCR results will be evaluated for pneumonia by lung tomography. It is planned to evaluate the sample taken from the naso-oropharynx in the partners of these women for SARS-CoV-2 infection by RT-PCR. In addition, in positive cases, RT-PCR was planned from the uterus and naso-oropharynx samples at 7-day intervals until the case turned negative. Results: RT-PCR test for SARS-CoV-2 was positive only in a sample taken from the uterus of one woman (7.6%). The naso-oropharyngeal sample of the same patient was negative, and the patient had no symptoms of COVID-19. No COVID-19-related lesion was observed in the lung tomography of this patient. The results of the RT-PCR test performed 7 days later with samples taken from the uterus and naso-pharynx were also negative. After the patient's positive RT-PCR result, a naso-oropharyngeal sample was taken from his partner. The RT-PCR test result for SARS-CoV-2 in the patient's partner was negative. Conclusion: The fact that the SARS-CoV-2 virus was negative in the naso-oropharyngeal sample and positive in the uterine sample in a pregnant woman who had a miscarriage suggests that the endometrium may be an entry route for the virus. These data suggest that the virus can lead to adverse pregnancy outcomes, including early pregnancy loss, even without known symptoms. A large number of studies are needed to evaluate the effects of common viruses on pregnancy beyond the expected and defined symptoms.

SARS-CoV-2 Transplacental Transmission: A Rare Occurrence? An Overview of the Protective Role of the Placenta

The outbreak of the coronavirus disease 2019 (COVID-19) pandemic, caused by novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global public health crisis, causing substantial concern especially to the pregnant population. Pregnant women infected with SARS-CoV-2 are at greater risk of devastating pregnancy complications such as premature delivery and stillbirth. Irrespective of the emerging reported cases of neonatal COVID-19, reassuringly, confirmatory evidence of vertical transmission is still lacking. The protective role of the placenta in limiting in utero spread of virus to the developing fetus is intriguing. The short- and long-term impact of maternal COVID-19 infection in the newborn remains an unresolved question. In this review, we explore the recent evidence of SARS-CoV-2 vertical transmission, cell-entry pathways, placental responses towards SARS-CoV-2 infection, and its potential effects on the offspring. We further discuss how the placenta serves as a defensive front against SARS-CoV-2 by exerting various cellular and molecular defense pathways. A better understanding of the placental barrier, immune defense, and modulation strategies involved in restricting transplacental transmission may provide valuable insights for future development of antiviral and immunomodulatory therapies to improve pregnancy outcomes.

Functional consequences of SARS-CoV-2 infection in pregnant women, fetoplacental unit, and neonate

The SARS-CoV-2 infection causes COVID-19 disease, characterized by acute respiratory distress syndrome, bilateral pneumonia, and organ failure. The consequences of maternal SARS-CoV-2 infection for the pregnant woman, fetus, and neonate are controversial. Thus, it is required to determine whether there is viral and non-viral vertical transmission in COVID-19. The disease caused by SARS-CoV-2 leads to functional alterations in asymptomatic and symptomatic pregnant women, the fetoplacental unit and the neonate. Several diseases of pregnancy, including COVID-19, affect the fetoplacental function, which causes in utero programming for young and adult diseases. A generalized inflammatory state and a higher risk of infection are seen in pregnant women with COVID-19. Obesity, diabetes mellitus, and hypertension may increase the vulnerability of pregnant women to infection by SARS-CoV-2. Alpha, Delta, and Omicron variants of SARS-CoV-2 show specific mutations that seem to increase the capacity of the virus to infect the pregnant woman, likely due to increasing its interaction via the virus S protein and angiotensin-converting enzyme 2 receptors. This review shows the literature addressing to what extent COVID-19 in pregnancy affects the pregnant woman, fetoplacental unit, and neonate. Prospective studies that are key in managing SARS-CoV-2 infection in pregnancy are discussed.

Tropism and Infectivity of Pandemic Influenza A H1N1/09 Virus in the Human Placenta

Influenza virus infection in pregnant women may put the fetus at higher risk; however, to date, there has been no detailed research about the expression of influenza virus receptors in the human placenta. We employed the lectin staining technique, which is a classic influenza virus receptor research method for studying the distribution of viral receptors in the human placenta. In addition, we examined the susceptibility of the human placenta to H1N1/09, by detecting viral proteins and RNA at different time points post-infection. We found that the human placenta expressed both avian and human influenza A virus receptors (α-2, 3-linked sialic acid and α-2, 6-linked sialic acid). In addition, H1N1/09 did not only infect the human placenta, but also replicated and was released into the culture media. We concluded that the human placenta is susceptible to the 2009 influenza A virus (H1N1/09) infection, and that particular attention should be paid to shielding pregnant women from infection during influenza season.

Characteristics of Placental Histopathology in Women with Uncomplicated Pregnancies Affected by SARS-CoV-2 Infection at the Time of Delivery: A Single-Center Experience

The aim of this study was, firstly, to analyze the histopathological characteristics of placentas in women with uneventful pregnancies and affected by COVID-19 at the time of delivery; and secondly, to correlate histological findings to maternal and neonatal characteristics. In our single-center prospective observational study, 46 placentas from term uncomplicated singleton pregnancies of patients with a documented SARS-CoV-2 infection at the time of delivery underwent histological examination. Despite a normal feto-maternal outcome, most of the placentas (82.6%) presented signs of maternal vascular malperfusion, while features of fetal vascular malperfusion were found in 54% of cases. No correlation was detected between maternal and neonatal characteristics and the severity of blood circulation disease, and abnormal findings were also described in asymptomatic patients. Moreover, we did not find any maternal symptoms or clinical details allowing for the prediction of abnormal placental findings in pregnancy complicated by COVID-19 infection. Our results suggest that SARS-CoV-2 infection during pregnancy could lead to acute placental dysfunction.

Infants Born Following SARS-CoV-2 Infection in Pregnancy

OBJECTIVES

To evaluate outcomes of neonates born to mothers with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy, the dynamics of placental transfer of maternal antibodies, and its persistence during infancy.

METHODS

Cohort study enrolling neonates born to mothers with SARS-CoV-2 infection in pregnancy. All infants were evaluated at birth. Those born to women with infection onset within 2 weeks before delivery were excluded from further analyses. Remaining infants underwent cerebral and abdominal ultrasound, fundoscopy evaluation, and were enrolled in a 12 month follow-up. Qualitative immunoglobulin G (IgG)/immunoglobulin M and quantitative IgG to S1/S2 subunits of spike protein were assessed in mother-neonate dyads within 48 hours postdelivery and during follow-up.

RESULTS

Between April 2020 and April 2021, 130 of 2745 (4.7%) neonates were born to mothers with SARS-CoV-2 infection in pregnancy, with 106 of 130 infections diagnosed before 2 weeks before delivery. Rates of preterm and cesarean delivery were comparable between women with and without infection (6% vs 8%, P = .57; 22% vs 32%, P = .06). No clinical or instrumental abnormalities were detected at birth or during follow-up. There was a positive correlation between maternal and neonatal SARS-CoV-2 IgG levels (r = 0.81, P < .001). Transplacental transfer ratio was higher after second-trimester maternal infections as compared with first and third trimester (P = .03). SARS-CoV-2 IgG level progressively decreased in all infants, with 89 of 92 (97%) infants seronegative at 6 months of age.

CONCLUSIONS

Clinical outcomes were favorable in all infants. Matching peak IgG level after infection and higher IgG transplacental transfer might result in the most durable neonatal passive immunity.

Review of Impact of COVID-19 on Maternal, Neonatal Outcomes, and Placental Changes

Coronavirus disease (COVID-19), caused by SARS-CoV-2, is a disease that has caused a global impact. COVID-19 is transmitted through airborne droplets, respiratory secretions, and direct contact. The pandemic has affected individuals of different ages, and studying the impact of COVID-19 on maternal and newborn outcomes is critical. In this review, we highlight the impact of COVID-19 infection in pregnancy and its repercussion in the maternal-fetal binomial. Physiological changes that occur during pregnancy have significant effects on the immune system, cardiopulmonary system, and coagulation, and these changes can result in an altered response to COVID-19 infection. The symptoms, risk factors, and maternal health consequences of COVID-19 were discussed. In addition, the impact of newborns born to mothers with COVID-19 was reviewed. Finally, placental changes and vertical transmission of COVID-19 during pregnancy were also discussed in this review.

COVID-19 in pregnancy: possible mechanisms not to be discounted

SARS-CoV-2 has infected more than 16 million people worldwide. Related complications and death from COVID-19 disease and their underlying pathophysiology are intensely investigated. Pregnant women are among the affected. Although the severity of disease in pregnancy does not appear to be increased, the effects of infection on pregnancy should not escape careful examination. The currently known receptor for the virus, ACE2, regulates the renin-angiotensin system and is increased during pregnancy. Virus-receptor interactions may have significant effects on placental function, fetal development, and maternal immunity. The manifestation of cardiovascular complications of infection produces the hypothesis that a significant effect of the virus may be its influence on the maternal vascular system. Interference with the vascular adaptations to pregnancy and the post-partum may have implications for concurrent and future pregnancies as well as for long-term cardiovascular health. We should not miss the opportunity to learn from this virus about the physiology of pregnancy.

SARS-CoV-2 in infant urine and fecal samples after in utero COVID-19 exposure

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a pandemic that has and will continue to affect many pregnant women. Knowledge regarding the risk of vertical transmission is limited. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) real-time reverse transcriptase-polymerase chain reaction (RT-PCR) of nasopharyngeal swabs typically have been used to confirm the diagnosis among infants, but whether the virus can be detected in other biological specimens, and therefore potentially transmitted in other ways, is unknown. Positive SARS-CoV-2 RT-PCR has been reported from feces and urine from adult patients. We hypothesize that the presence of SARS-CoV-2 in infant urine and fecal samples after prenatal COVID-19 exposure is low.

METHODS

We examined the presence of SARS-CoV-2 RNA using RT-PCR in urine and fecal samples among 42 infants born to SARS-CoV-2-infected mothers during different stages of pregnancy.

RESULTS

A urine sample was collected from 39 of 42 infants and fecal samples from all 42 infants shortly after birth. Although the majority of the women had the symptomatic disease (85.6%), we were unable to detect the presence of SARS-CoV-2 virus from any infant urine or fecal samples.

CONCLUSIONS

SARS-CoV-2 was not detected in infant urine or feces after maternal infection during pregnancy, providing further evidence for low rates of perinatal transmission.

IMPACT

SARS-CoV-2 was not detected in the urine or feces of infants of mothers with COVID-19 during various time points in pregnancy. This study provides further evidence for low rates of perinatal transmission of SARS-CoV-2. Results help to provide guidance on perinatal care practices for infants exposed to COVID-19 in utero.

The rate of SARS-CoV-2 among asymptomatic non-immunised low-risk parturient women between the two waves

This study was conducted to evaluate the rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and immunity among asymptomatic non-immunised low-risk parturient women and their newborns. A cross-sectional study conducted in a tertiary hospital during the nadir period of new cases in Egypt. All asymptomatic pregnant, low risk and non-immunised women were included. All eligible participants had been subjected to SARS-CoV-2 nasopharyngeal swabs according to CDC and sampling of maternal and umbilical blood to evaluate the presence of coronavirus disease 2019 (COVID-19) IgM and IgG antibodies by immunochromatographic assay. Two cases out of 171 (1.2%) parturient women were tested positive for PCR swab to COVID-19 infection. Furthermore, COVID-19 IgG and IgM antibodies testing showed that 67.8% of women were negative for both IgG and IGM, 24.6% were positive for IgG only, 4.1% were positive for IgM only, while 3.5% were positive for both IgG and IgM. Regarding neonatal testing for immunity, 28.1% of the neonates were positive to IgG only and none for IgM.The rate of positive PCR patients among asymptomatic low-risk parturient women was 1.2%. About quarter of women had got herd immunity as evident by positive IgG antibodies. IgG antibodies transferred to the neonates in almost all cases.Impact StatementWhat is already known on this subject? Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global public health emergency. Asymptomatic pregnant women with coronavirus disease can transmit their infection to their newborn, family members and the health care providers.What do the results of this study add? The study showed very low (1.2%) prevalence of COVID positive cases among asymptomatic pregnant women admitted to our facility. Only two cases out of 171 parturient women tested PCR positive for COVID-19 infection (1.2%). SARS-Cov-2 IgG and IgM antibodies testing showed, about a quarter (24.6%) were positive for IgG antibodies, 4.1% were positive for IgM antibodies, while 3.5% were positive for both IgG and IgM. On the other hand, 28.1% of the neonates were positive to IgG only and none of the newborns had had IgM antibodies in their cord blood.What are the implications of these findings for clinical practice and/or further research? The first wave of COVID-19 pandemic in Egypt left behind at least a quarter of pregnant women with a positive antibody denoting some immunity. This immunity is usually transmitted to the neonates in almost all cases.

Intrauterine Vertical Transmission of SARS-CoV-2 Infection Among Confirmed Cases of Pregnant Women: “A Double Burden for the Pregnant Women”—A Systematic Review

Introduction. The world health organization (WHO) has declared the outbreak of novel coronavirus (2019-nCoV), which is now known as Coronavirus Disease 2019 (COVID-19). Whereas, its quick global spread has resulted in a worldwide pandemic. The present review article was intended to evaluate intrauterine vertical transmission of SARS-CoV-2 infection among confirmed cases of pregnant women. Methods. Web of Science, EMBASE, PubMed, African Journals OnLine, Scopus, PsycINFO, HINARI, Cochrane Library, Wiley Online Library, and Google scholar were used for search. Result. A total of 43 articles were included in to this systematic review. A total of 1,300 neonates born from pregnant women confirmed for COVI-19 were tested for SARS-CoV-2 infection by real-time reverse transcriptase–polymerase chain reaction (RT-PCR). From the 1,300 neonates tested for SARS-CoV-2 infection, 93 neonates were found positive for this infection by RT-PCR. From this systematic review finding, the vertical transmission rate of SARS-CoV-2 infection was 7.15%. This pandemic has stressed the entire public, particularly pregnant women and healthcare providers, while it challenged antenatal care and postnatal care by far. Thus, even being under lockdown in the middle of a global pandemic is stressful enough. Therefore, imagine the added burden of being pregnant, which could be a double burden for these women. Conclusion. There is no concrete evidence of vertical transmission of SARS-CoV-2. Therefore, due to the limited number of clinical evidences, obstetricians, pediatricians, and other healthcare providers should continuously update their knowledge and be conscious about the transmission of SARS-CoV-2 vertically during pregnancy.

Stillbirth after COVID-19 in Unvaccinated Mothers Can Result from SARS-CoV-2 Placentitis, Placental Insufficiency, and Hypoxic Ischemic Fetal Demise, Not Direct Fetal Infection: Potential Role of Maternal Vaccination in Pregnancy

Stillbirth is a recently recognized complication of COVID-19 in pregnant women. Other congenitally transmitted infections from viruses, bacteria and parasites can cause stillbirth by infecting fetal organs following transplacental transmission of the agent from the maternal bloodstream. However, recent research on pregnant women with COVID-19 having stillbirths indicates that there is another mechanism of stillbirth that can occur in placentas infected with SARS-CoV-2. In these cases, viral infection of the placenta results in SARS-CoV-2 placentitis, a combination of concurrent destructive findings that include increased fibrin deposition which typically reaches the level of massive perivillous fibrin deposition, chronic histiocytic intervillositis and trophoblast necrosis. These three pathological lesions, in some cases together with placental hemorrhage, thrombohematomas and villitis, result in severe and diffuse placental parenchymal destruction. This pathology can involve greater than one-half of the placental volume, averaging 77% in the largest study of 68 cases, effectively rendering the placenta incapable of performing its function of oxygenating the fetus. This destructive placental process can lead to stillbirth and neonatal death via malperfusion and placental insufficiency which is independent of fetal infection. Fetal autopsies show no evidence that direct infection of fetal organs is contributory. Because all mothers examined have been unvaccinated, maternal vaccination may prevent viremia and consequent placental infection.

Placental Tissue Destruction and Insufficiency from COVID-19 Causes Stillbirth and Neonatal Death from Hypoxic-Ischemic Injury: A Study of 68 Cases with SARS-CoV-2 Placentitis from 12 Countries

CONTEXT.—

Perinatal death is an increasingly important problem as the COVID-19 pandemic continues, but the mechanism of death has been unclear.

OBJECTIVE.—

To evaluate the role of the placenta in causing stillbirth and neonatal death following maternal infection with COVID-19 and confirmed placental positivity for SARS-CoV-2.

DESIGN.—

Case-based retrospective clinico-pathological analysis by a multinational group of 44 perinatal specialists from 12 countries of placental and autopsy pathology findings from 64 stillborns and 4 neonatal deaths having placentas testing positive for SARS-CoV-2 following delivery to mothers with COVID-19.

RESULTS.—

All 68 placentas had increased fibrin deposition and villous trophoblast necrosis and 66 had chronic histiocytic intervillositis, the three findings constituting SARS-CoV-2 placentitis. Sixty-three placentas had massive perivillous fibrin deposition. Severe destructive placental disease from SARS-CoV-2 placentitis averaged 77.7% tissue involvement. Other findings included multiple intervillous thrombi (37%; 25/68) and chronic villitis (32%; 22/68). The majority (19, 63%) of the 30 autopsies revealed no significant fetal abnormalities except for intrauterine hypoxia and asphyxia. Among all 68 cases, SARS-CoV-2 was detected from a body specimen in 16 of 28 cases tested, most frequently from nasopharyngeal swabs. Four autopsied stillborns had SARS-CoV-2 identified in internal organs.

CONCLUSIONS.—

The pathology abnormalities composing SARS-CoV-2 placentitis cause widespread and severe placental destruction resulting in placental malperfusion and insufficiency. In these cases, intrauterine and perinatal death likely results directly from placental insufficiency and fetal hypoxic-ischemic injury. There was no evidence that SARS-CoV-2 involvement of the fetus had a role in causing these deaths.

Maternal-fetal immune responses in pregnant women infected with SARS-CoV-2

Pregnant women represent a high-risk population for severe/critical COVID-19 and mortality. However, the maternal-fetal immune responses initiated by SARS-CoV-2 infection, and whether this virus is detectable in the placenta, are still under investigation. Here we show that SARS-CoV-2 infection during pregnancy primarily induces unique inflammatory responses at the maternal-fetal interface, which are largely governed by maternal T cells and fetal stromal cells. SARS-CoV-2 infection during pregnancy is also associated with humoral and cellular immune responses in the maternal blood, as well as with a mild cytokine response in the neonatal circulation (i.e., umbilical cord blood), without compromising the T-cell repertoire or initiating IgM responses. Importantly, SARS-CoV-2 is not detected in the placental tissues, nor is the sterility of the placenta compromised by maternal viral infection. This study provides insight into the maternal-fetal immune responses triggered by SARS-CoV-2 and emphasizes the rarity of placental infection.

SARS-CoV-2, Zika viruses and mycoplasma: Structure, pathogenesis and some treatment options in these emerging viral and bacterial infectious diseases

The molecular evolution of life on earth along with changing environmental, conditions has rendered mankind susceptible to endemic and pandemic emerging infectious diseases. The effects of certain systemic viral and bacterial infections on morbidity and mortality are considered as examples of recent emerging infections. Here we will focus on three examples of infections that are important in pregnancy and early childhood: SARS-CoV-2 virus, Zika virus, and Mycoplasma species. The basic structural characteristics of these infectious agents will be examined, along with their general pathogenic mechanisms. Coronavirus infections, such as caused by the SARS-CoV-2 virus, likely evolved from zoonotic bat viruses to infect humans and cause a pandemic that has been the biggest challenge for humanity since the Spanish Flu pandemic of the early 20th century. In contrast, Zika Virus infections represent an expanding infectious threat in the context of global climate change. The relationship of these infections to pregnancy, the vertical transmission and neurological sequels make these viruses highly relevant to the topics of this special issue. Finally, mycoplasmal infections have been present before mankind evolved, but they were rarely identified as human pathogens until recently, and they are now recognized as important coinfections that are able to modify the course and prognosis of various infectious diseases and other chronic illnesses. The infectious processes caused by these intracellular microorganisms are examined as well as some general aspects of their pathogeneses, clinical presentations, and diagnoses. We will finally consider examples of treatments that have been used to reduce morbidity and mortality of these infections and discuss briefly the current status of vaccines, in particular, against the SARS-CoV-2 virus. It is important to understand some of the basic features of these emerging infectious diseases and the pathogens involved in order to better appreciate the contributions of this special issue on how infectious diseases can affect human pregnancy, fetuses and neonates.

Adverse pregnancy outcomes during the COVID-19 lockdown. A descriptive study

BACKGROUND

The ongoing spread coronavirus disease worldwide has caused major disruptions and led to lockdowns. Everyday lifestyle changes and antenatal care inaccessibility during the coronavirus disease 2019 (COVID-19) pandemic have variable results that affect pregnancy outcomes. This study aimed to assess the alterations in stillbirth, neonatal-perinatal mortality, preterm birth, and birth weight during the COVID-19 national lockdown.

METHODS

We used the data from the Jordan stillbirths and neonatal death surveillance system to compare pregnancy outcomes (gestational age, birth weight, small for gestational age, stillbirth, neonatal death, and perinatal death) between two studied periods (11 months before the pandemic (May 2019 to March 2020) vs. 9 months during the pandemic (April 2020 to March 1st 2020). Separate multinomial logistic and binary logistic regression models were used to compare the studied outcomes between the two studied periods after adjusting for the effects of mother's age, income, education, occupation, nationality, health sector, and multiplicity.

RESULTS

There were 31106 registered babies during the study period; among them, 15311 (49.2%) and 15795 (50.8%) births occurred before and during the COVID-19 lockdown, respectively. We found no significant differences in preterm birth and stillbirth rates, neonatal mortality, or perinatal mortality before and during the COVID-19 lockdown. Our findings report a significantly lower incidence of extreme low birth weight (ELBW) infants (<1kg) during the COVID-19 lockdown period than that before the lockdown (adjusted OR 0.39, 95% CI 0.3-0.5: P value <0.001) CONCLUSIONS: During the COVID-19 lockdown period, the number of infants born with extreme low birth weight (ELBW) decreased significantly. More research is needed to determine the impact of cumulative socio-environmental and maternal behavioral changes that occurred during the pandemic on the factors that contribute to ELBW infants.

Mother-to-child transmission of severe acute respiratory syndrome coronavirus 2: review of classification systems and systematic reviews

PURPOSE OF REVIEW

To review the various classification systems for mother-to-child transmission (MTCT) of SARS-CoV-2 and collate existing evidence on systematic reviews of MTCT of SARS-CoV-2.

RECENT FINDINGS

To-date, there are three classification systems for MTCT of SARS-CoV-2, including the WHO classification developed by expert consensus, based on in-utero, intrapartum and postnatal exposure of the babies to the virus. The systems variously classify babies tested for suspected SARS-CoV-2 infection as confirmed, probable, possible, indeterminate and unlikely for MTCT. To-date, 68 systematic reviews have been published between December 2019 and March 2021 on SARS-CoV-2 MTCT. Most of the reviews included cases series and case reports in their pooling of data, and often used SARS-CoV-2 infection and test positivity interchangeably.

SUMMARY

Several classification systems are available to assist in determining the timing of SARS-CoV-2 infection in new-borns. Existing reviews of MTCT are of poor quality and report variable rates of SARS-CoV-2 positivity. A high-quality systematic review is needed on the extent of confirmed vertical transmission of SARS-CoV-2, risk factors for MTCT of SARS-CoV-2, the prevalence and persistence of viral particles or immunological response in reported biological samples. Primary studies should categorize MTCT using classifications, such as WHO classification system that considers the strength of the timing of classification and persistence of positivity, taking into account the sterility of the collected samples.

A meta-analysis for the risk and prevalence of preeclampsia among pregnant women with COVID-19

Preeclampsia and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection are both life-threatening disorders when they occur during pregnancy. They are similarly characterized by systemic immune activation and have a deleterious effect on maternal endothelial cells. During the coronavirus disease-2019 (COVID-19) pandemic, there were reports of preeclampsia or a preeclampsia-like syndrome occurring in pregnant women with SARS-CoV-2 infection. We performed a meta-analysis to estimate the risk and prevalence of preeclampsia and SARS-CoV-2 infection in pregnant women. A comprehensive literature search was conducted in PubMed, Web of Science, Scopus, and China National Knowledge Infrastructure to identify all relevant studies published up to February 29, 2020. All studies that reported the prevalence of preeclampsia in pregnant women with SARS-CoV-2 infection were selected. A total of 10 case-control studies and 15 case series met our inclusion criteria. Pooled data revealed no significant difference between infected pregnant women and uninfected pregnant women for the risk of preeclampsia [odds ratio (OR)=1.676, 95% confidence interval (CI) 0.679-4.139, p=0.236]. The stratified analysis revealed significant risk in the infected Asian pregnant women (OR=2.637, 95% CI 1.030-6.747, p=0.043), but not Caucasian. The prevalence of preeclampsia was 8.2% (95% CI 0.057-0.117) in infected pregnant women with COVID-19 in the overall population. Its prevalence was highest in North America (10.7%), followed by Asian (7.9%), Caucasian (6.7%), European (4.9%), and West Asian (2.6%) infected pregnant women. Our pooled data showed that the prevalence of preeclampsia in pregnant women with SARS-CoV-2 infection was 8.2%. However, there was no increased risk of occurrence of preeclampsia among pregnant women with SARS-CoV-2 infection.

The Effects of COVID-19 on the Placenta During Pregnancy

Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic. The virus primarily affects the lungs where it induces respiratory distress syndrome ranging from mild to acute, however, there is a growing body of evidence supporting its negative effects on other system organs that also carry the ACE2 receptor, such as the placenta. The majority of newborns delivered from SARS-CoV-2 positive mothers test negative following delivery, suggesting that there are protective mechanisms within the placenta. There appears to be a higher incidence of pregnancy-related complications in SARS-CoV-2 positive mothers, such as miscarriage, restricted fetal growth, or still-birth. In this review, we discuss the pathobiology of COVID-19 maternal infection and the potential adverse effects associated with viral infection, and the possibility of transplacental transmission.

Molecular Pathology Demonstration of SARS-CoV-2 in Cytotrophoblast from Placental Tissue with Chronic Histiocytic Intervillositis, Trophoblast Necrosis and COVID-19

A subset of placentas from pregnant women having the SARS-CoV-2 infection have been found to be infected with the coronavirus using molecular pathology methods including immunohistochemistry and RNA in situ hybridization. These infected placentas can demonstrate several unusual findings which occur together-chronic histiocytic intervillositis, trophoblast necrosis and positive staining of the syncytiotrophoblast for SARS-CoV-2. They frequently also have increased fibrin deposition, which can be massive in some cases. Syncytiotrophoblast is the most frequent fetal-derived cell type to be positive for SARS-CoV-2. It has recently been shown that in a small number of infected placentas, villous stromal macrophages, termed Hofbauer cells, and villous capillary endothelial cells can also stain positive for SARS-CoV-2. This report describes a placenta from a pregnant woman with SARS-CoV-2 that had chronic histiocytic intervillositis, trophoblast necrosis, increased fibrin deposition and positive staining of the syncytiotrophoblast for SARS-CoV-2. In addition, molecular pathology testing including RNAscope and immunohistochemistry for SARS-CoV-2 and double-staining immunohistochemistry using antibodies to E-cadherin and GATA3 revealed that cytotrophoblast cells stained intensely for SARS-CoV-2. All of the cytotrophoblast cells that demonstrated positive staining for SARS-CoV-2 were in direct physical contact with overlying syncytiotrophoblast that also stained positive for the virus. The pattern of cytotrophoblast staining for SARS-CoV-2 was patchy, and there were chorionic villi having diffuse positive staining of the syncytiotrophoblast for SARS-CoV-2, but without staining of cytotrophoblast. This first detailed description of cytotrophoblast involvement by SARS-CoV-2 adds another fetal cell type from infected placentas that demonstrate viral staining.

Hofbauer cells and coronavirus disease 2019 (COVID-19) in pregnancy: Molecular pathology analysis of villous macrophages, endothelial cells, and placental findings from 22 placentas infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with and without fetal transmission

CONTEXT

- Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can undergo maternal-fetal transmission, heightening interest in the placental pathology findings from this infection. Transplacental SARS-CoV-2 transmission is typically accompanied by chronic histiocytic intervillositis together with necrosis and positivity of syncytiotrophoblast for SARSCoV-2. Hofbauer cells are placental macrophages that have been involved in viral diseases including HIV and Zika virus, but their involvement in SARS-CoV-2 in unknown.

OBJECTIVE

- To determine whether SARS-CoV-2 can extend beyond the syncytiotrophoblast to enter Hofbauer cells, endothelium and other villous stromal cells in infected placentas of liveborn and stillborn infants.

DESIGN

- Case-based retrospective analysis by 29 perinatal and molecular pathology specialists of placental findings from a preselected cohort of 22 SARS-CoV-2-infected placentas delivered to pregnant women testing positive for SARS-CoV-2 from 7 countries. Molecular pathology methods were used to investigate viral involvement of Hofbauer cells, villous capillary endothelium, syncytiotrophoblast and other fetal-derived cells.

RESULTS

- Chronic histiocytic intervillositis and trophoblast necrosis was present in all 22 placentas (100%). SARS-CoV-2 was identified in Hofbauer cells from 4/22 placentas (18%). Villous capillary endothelial staining was positive in 2/22 cases (9%), both of which also had viral positivity in Hofbauer cells. Syncytiotrophoblast staining occurred in 21/22 placentas (95%). Hofbauer cell hyperplasia was present in 3/22 placentas (14%). In the 7 cases having documented transplacental infection of the fetus, 2 occurred in placentas with Hofbauer cell staining positive for SARS-CoV-2.

CONCLUSIONS

- SARS-CoV-2 can extend beyond the trophoblast into the villous stroma, involving Hofbauer cells and capillary endothelial cells, in a small number of infected placentas. Most cases of SARS-CoV-2 transplacental fetal infection occur without Hofbauer cell involvement.

A Case of COVID-19 Pregnancy Complicated with Hydrops Fetalis and Intrauterine Death

Coronavirus disease 2019 (COVID-19) has rapidly evolved into a worldwide pandemic causing a serious global public health problem. The risk of vertical transmission of SARS-CoV-2 is still debated, and the consequences of this virus on pregnant women and their fetuses remain unknown. We report a case of pregnancy complicated with hydrops fetalis that developed 7 weeks after recovery from a mild SARS-CoV-2 infection, leading to intrauterine death of the foetus. Evidence of SARS-CoV-2 placentitis was demonstrated by the presence of viral particles in the placenta identified by immunohistochemistry. As we excluded all possible etiological factors for non-immunologic hydrops fetalis, we believe that the fetal consequences of our case are related to vertical transmission of SARS-CoV-2 virus. To the best of our knowledge, this is the second reported case in the literature of COVID-19 infection complicated with hydrops fetalis and intrauterine fetal demise.

Vertical transmission of SARS-CoV-2: A prospective cross-sectional study from a tertiary center

The aim was to investigate the association of the delivery mode and vertical transmission of severe acute respiratory syndrome coronavirus‐2 (SARS‐CoV‐2) through the samples of vaginal secretions, placenta, cord blood, or amniotic fluid as well as the neonatal outcomes. This cross‐sectional study presents an analysis of prospectively gathered data collected at a single tertiary hospital. Sixty‐three pregnant women with confirmed coronavirus disease 2019 (COVID‐19) participated in the study. Vertical transmission of SARS‐CoV‐2 was analyzed with reverse transcriptase‐polymerase chain reaction (RT‐PCR) tests and blood tests for immunoglobulin G (IgG)–immunoglobulin M (IgM) antibodies. All patients were in the mild or moderate category for COVID‐19. Only one placental sample and two of the vaginal secretion samples were positive for SARS‐CoV‐2. Except for one, all positive samples were obtained from patients who gave birth by cesarean. All cord blood and amniotic fluid samples were negative for SARS‐CoV‐2. Two newborns were screened positive for COVID‐19 IgG–IgM within 24 h after delivery, but the RT‐PCR tests were negative. A positive RT‐PCR result was detected in a neof a mother whose placenta, cord blood, amniotic fluid, and vaginal secretions samples were negative. He died due to pulmonary hemorrhage on the 11th day of life. In conclusion, we demonstrated that SARS‐CoV‐2 can be detectable in the placenta or vaginal secretions of pregnant women. Detection of the virus in the placenta or vaginal secretions may not be associated with neonatal infection. Vaginal delivery may not increase the incidence of neonatal infection, and cesarean may not prevent vertical transmission. The decision regarding the mode of delivery should be based on obstetric indications and COVID‐19 severity.

Proportion and mortality of Iranian diabetes mellitus, chronic kidney disease, hypertension and cardiovascular disease patients with COVID-19: a meta-analysis

BACKGROUND

Currently, the number of patients with SARS-COV-2 infection has increased rapidly in Iran, but the risk and mortality of SARS-COV-2 infection in Iranian patients with diabetes mellitus (DM), chronic kidney disease (CKD), hypertension and cardiovascular diseases (CVDs) still not clear. The aim of this meta-analysis was to estimate the proportion and mortality of SARS-COV-2 in these patients.

METHODS

A comprehensive literature search was carried out in PubMed, Web of Sciences, Cochrane Library, EMBASE, CNKI, SciELO, and other databases to identify all relevant studies published up to 10 January, 2020. The proportion and mortality in the patients were assessed by odd ratio (OR) and the corresponding 95 % confidence interval (95 % CI).

RESULTS

A total of ten case-series including 11,755 cases with SARS-COV-2 infection and 942 deaths were selected. Among them, there were total of 791 DM patients with 186 deaths, 225 CKD patients with 45 deaths, 790 hypertension cases with 86 deaths, and 471 CVDs cases with 60 deaths. Pooled data revealed that the proportion of SARS-COV-2 infection in the patients with hypertension, DM, CVDs and CKD were 21.1 %, 16.3 %, 14.0 % and 5.0 %, respectively. Moreover, the SARS-COV-2 infection were associated with an increased risk of mortality in DM (OR = 0.549, CI 95 % 0.448-0.671, p ≤ 0.001) and CKD (OR = 0.552, 95 % CI 0.367-0.829, p = 0.004) patients, but not hypertension and CVDs. There was no publication bias.

CONCLUSIONS

Our pooled data showed that the proportion of SARS-COV-2 infection was the highest in the Iranian patients with hypertension (21.1 %) followed by DM (16.3 %), CVDs (14.0 %) and CKD (5.0 %). Moreover, DM and CKD in patients with SARS-COV-2 infection were associated with a 0.549 and 0.552-fold increase in mortality, respectively. Clinicians in Iran should be aware of these findings, to identifying patients at higher risk and inform interventions to reduce the risk of death. Moreover, well-designed, large-scale and multicenter studies are needed to improve and validate our findings.

Vertical transmission and COVID-19: a scoping review

OBJECTIVE

Analyze available evidence related to SARS-CoV-2 infection and vertical transmission.

METHODS

Scoping review, according to the Joanna Briggs Institute and PRISMA-ScR. Searches were conducted in five electronic databases to find publications about coronavirus infection and vertical transmission. Data were extracted, analyzed and synthesized by three independent researchers using a descriptive approach.

RESULTS

The search resulted in 76 publications. After selective steps, 15 articles - retrospective descriptive or case studies - were analyzed, all in English. In order to track the infection, specimens were collected from neonates through nasal swabs and C-reactive protein from breast milk, cord blood, amniotic fluid, placenta and vaginal secretion was analyzed. A small percentage of neonates tested positive for COVID-19, but these cases were not attributed to vertical transmission.

CONCLUSION

Vertical transmission could not be demonstrated. Research protocol registered with the Open Science Framework (https://osf.io/fawmv).

Neonatal SARS-CoV-2 Infection: Practical Tips

The recent viral pandemic in Wuhan, Hubei, China has led to the identification of a new species of beta-coronavirus, able to infect humans, the 2019-nCoV, later named SARS-CoV-2. SARS-CoV-2 causes a clinical syndrome named COVID-19, which presents with a spectrum of symptoms ranging from mild upper respiratory tract infection to severe pneumonia, with acute respiratory distress syndrome and frequent death. All age groups are susceptible to the infection, but children, especially infants, seem to be partially spared, having a more favorable clinical course than other age groups. There is currently no clear evidence showing vertical transmission and intrauterine SARS-CoV-2 infection in fetuses of women developing COVID-19 pneumonia in late pregnancy, and even if transmission is possible, the SARS-CoV2 positivity of the mother does not require delivery by caesarean section, does not contraindicate the management of the infant in rooming-in and allows breastfeeding. This review provides an overview on the biology of the virus, on the pathogenesis of the infection, with particular attention to pregnancy and neonatal age, on the clinical presentation of infection in newborns and young infants and summarizes the international recommendations currently available on the clinical care of neonates with SARS-CoV2 infection or at risk of catching the virus. The main objective of the review is to provide an update especially focused to the clinical management of COVID-19 infection in the perinatal and neonatal age.

Coronavirus Diseases in Pregnant Women, the Placenta, Fetus, and Neonate

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the etiological agent of coronavirus disease 2019 (COVID-19), is similar to two other coronaviruses, severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), in causing life-threatening respiratory infections and systemic complications in both children and adults. As the COVID-19 pandemic has continued to spread globally, increasing numbers of pregnant women have become infected, raising concern not only for their health but also for the health of their infants. This chapter discusses the effects of coronavirus infections, e.g., MERS, SARS, and COVID 19, on pregnancy and describes the evolving knowledge of COVID 19 among pregnant women. The physiological changes that occur in pregnancy, especially changes in the immune system, are reviewed in terms of their effect on susceptibility to infectious diseases. The effects of COVID-19 on the placenta, fetus, and neonate are also reviewed, including potential clinical outcomes and issues relating to testing and diagnosis. The potential mechanisms of vertical transmission of the virus between pregnant women and their infants are analyzed, including intrauterine, intrapartum, and postpartum infections. Several recent studies have reported the detection of SARS-CoV-2 in tissues from the fetal side of the placenta, permitting the diagnosis of transplacental infection of the fetus by SARS-CoV-2. Placentas from infected mothers in which intrauterine transplacental transmission of SARS-CoV-2 has occurred demonstrate an unusual combination of pathology findings which may represent risk factors for placental as well as fetal infection.

Chronic Histiocytic Intervillositis With Trophoblast Necrosis Is a Risk Factor Associated With Placental Infection From Coronavirus Disease 2019 (COVID-19) and Intrauterine Maternal-Fetal Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Transmission in Live-Born and Stillborn Infants

CONTEXT.—

The number of neonates with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is increasing, and in a few there are reports of intrauterine infection.

OBJECTIVE.—

To characterize the placental pathology findings in a preselected cohort of neonates infected by transplacental transmission arising from maternal infection with SARS-CoV-2, and to identify pathology risk factors for placental and fetal infection.

DESIGN.—

Case-based retrospective analysis by a multinational group of 19 perinatal specialists of the placental pathology findings from 2 cohorts of infants delivered to mothers testing positive for SARS-CoV-2: live-born neonates infected via transplacental transmission who tested positive for SARS-CoV-2 after delivery and had SARS-CoV-2 identified in cells of the placental fetal compartment by molecular pathology, and stillborn infants with syncytiotrophoblast positive for SARS-CoV-2.

RESULTS.—

In placentas from all 6 live-born neonates acquiring SARS-CoV-2 via transplacental transmission, the syncytiotrophoblast was positive for coronavirus using immunohistochemistry, RNA in situ hybridization, or both. All 6 placentas had chronic histiocytic intervillositis and necrosis of the syncytiotrophoblast. The 5 stillborn/terminated infants had placental pathology findings that were similar, including SARS-CoV-2 infection of the syncytiotrophoblast, chronic histiocytic intervillositis, and syncytiotrophoblast necrosis.

CONCLUSIONS.—

Chronic histiocytic intervillositis together with syncytiotrophoblast necrosis accompanies SARS-CoV-2 infection of syncytiotrophoblast in live-born and stillborn infants. The coexistence of these 2 findings in all placentas from live-born infants acquiring their infection prior to delivery indicates that they constitute a pathology risk factor for transplacental fetal infection. Potential mechanisms of infection of the placenta and fetus with SARS-CoV-2, and potential future studies, are discussed.

Neonatal SARS-CoV-2 Infections in Breastfeeding Mothers

OBJECTIVES

To assess infection rates predischarge and postdischarge in breast milk-fed newborns with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive mothers who were separated postdelivery from their mothers and discharged from the hospital. Also, we aim to evaluate breastfeeding rates predischarge and postdischarge.

METHODS

Nasopharyngeal swabs for SARS-CoV-2 were obtained from symptomatic and high-risk women in the delivery room. Mothers with positive SARS-CoV-2 test results were separated from the newborns. Newborns were screened within 48 hours of delivery, and anti-infectious guidelines were imparted to the mothers before discharge. Rescreening took place ≥14 days postdischarge. Data regarding SARS-CoV-2-positive household members and breastfeeding were obtained by follow-up phone calls.

RESULTS

A total of 73 newborns of SARS-CoV-2-positive mothers were born in Israel during the ∼3-month period under study. Overall, 55 participated in this study. All neonates tested negative for the virus postdelivery. A total 74.5% of the neonates were fed unpasteurized expressed breast milk during the postpartum separation until discharge. Eighty-nine percent of the neonates were discharged from the hospital after their mothers were instructed in anti-infection measures. In 40% of the households, there were additional SARS-CoV-2-positive residents. A total of 85% of the newborns were breastfed postdischarge. Results for all 60% of the newborns retested for SARS-CoV-2 postdischarge were negative.

CONCLUSIONS

No viral infection was identified in neonates born to and separated from their SARS-CoV-2-positive mothers at birth and subsequently fed unpasteurized breast milk. All infants breastfed at home remained SARS-CoV-2 negative. These findings may provide insights regarding the redundancy of postpartum mother-newborn separation in SARS-CoV-2-positive women and, assuming precautions are adhered to, support the safety of breast milk.

Comparisons of the immunological landscape between COVID-19, influenza, and respiratory syncytial virus patients by clustering analysis

BACKGROUND

COVID-19 has stronger infectivity and a higher risk for severity than most other contagious respiratory illnesses. The mechanisms underlying this difference remain unclear.

METHODS

We compared the immunological landscape between COVID-19 and two other contagious respiratory illnesses (influenza and respiratory syncytial virus (RSV)) by clustering analysis of the three diseases based on 27 immune signatures' scores.

RESULTS

We identified three immune subtypes: Immunity-H, Immunity-M, and Immunity-L, which displayed high, medium, and low immune signatures, respectively. We found 20%, 35.5%, and 44.5% of COVID-19 cases included in Immunity-H, Immunity-M, and Immunity-L, respectively; all influenza cases were included in Immunity-H; 66.7% and 33.3% of RSV cases belonged to Immunity-H and Immunity-L, respectively. These data indicate that most COVID-19 patients have weaker immune signatures than influenza and RSV patients, as evidenced by 22 of the 27 immune signatures having lower enrichment scores in COVID-19 than in influenza and/or RSV. The Immunity-M COVID-19 patients had the highest expression levels of ACE2 and IL-6 and lowest viral loads and were the youngest. In contrast, the Immunity-H COVID-19 patients had the lowest expression levels of ACE2 and IL-6 and highest viral loads and were the oldest. Most immune signatures had lower enrichment levels in the intensive care unit (ICU) than in non-ICU patients. Gene ontology analysis showed that the innate and adaptive immune responses were significantly downregulated in COVID-19 versus healthy individuals.

CONCLUSIONS

Compared to influenza and RSV, COVID-19 displayed significantly different immunological profiles. Elevated immune signatures are associated with better prognosis in COVID-19 patients.

SARS-CoV-2 ACE2 and TMPRSS2 Receptor Protein Expression Patterns Throughout Gestation

We previously demonstrated that the late gestation placental expression pattern of ACE2 (the primary SARS-CoV-2 receptor) is localized to the villous syncytiotrophoblast (ST), usually in a polarized membranous pattern at the ST base sparing the apical surface (that directly exposed to maternal blood). We found that the late gestation placental expression pattern of TMPRSS2 (the spike proteinase required for SARS-CoV-2 cellular infection), is usually absent in the trophoblast but rarely, weakly expressed in the placental endothelium. We now show the developmental protein expression patterns of ACE2 and TMPRSS2 by immunohistochemistry throughout gestation, from first through third trimester. We found TMPRSS2 expression was rarely detectable in villous endothelium and very rarely detectable in the ST across gestation. We found ACE2 expression varied during gestation with circumferential ST expression more common in early gestations and polarized expression more common in later gestation. Although this study is small, these preliminary results suggest that earlier gestation pregnancies may be more vulnerable to infection than later gestation pregnancies.

Molecular Pathology Analysis of SARS-CoV-2 in Syncytiotrophoblast and Hofbauer Cells in Placenta from a Pregnant Woman and Fetus with COVID-19

A small number of neonates delivered to women with SARS-CoV-2 infection have been found to become infected through intrauterine transplacental transmission. These cases are associated with a group of unusual placental pathology abnormalities that include chronic histiocytic intervillositis, syncytiotrophoblast necrosis, and positivity of the syncytiotrophoblast for SARS-CoV-2 antigen or RNA. Hofbauer cells constitute a heterogeneous group of immunologically active macrophages that have been involved in transplacental infections that include such viral agents as Zika virus and human immunodeficiency virus. The role of Hofbauer cells in placental infection with SARS-CoV-2 and maternal-fetal transmission is unknown. This study uses molecular pathology techniques to evaluate the placenta from a neonate infected with SARS-CoV-2 via the transplacental route to determine whether Hofbauer cells have evidence of infection. We found that the placenta had chronic histiocytic intervillositis and syncytiotrophoblast necrosis, with the syncytiotrophoblast demonstrating intense positive staining for SARS-CoV-2. Immunohistochemistry using the macrophage marker CD163, SARS-CoV-2 nucleocapsid protein, and double staining for SARS-CoV-2 with RNAscope and anti-CD163 antibody, revealed that no demonstrable virus could be identified within Hofbauer cells, despite these cells closely approaching the basement membrane zone of the infected trophoblast. Unlike some other viruses, there was no evidence from this transmitting placenta for infection of Hofbauer cells with SARS-CoV-2.

Term Human Placental Trophoblasts Express SARS-CoV-2 Entry Factors ACE2, TMPRSS2, and Furin

The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has had a massive impact on human lives worldwide. While the airborne SARS-CoV-2 primarily affects the lungs, viremia is not uncommon. As placental trophoblasts are directly bathed in maternal blood, they are vulnerable to SARS-CoV-2. Intriguingly, the human fetus is largely spared from SARS-CoV-2 infection. We tested whether the human placenta expresses the main SARS-CoV-2 entry factors angiotensin-converting enzyme 2 (ACE2), transmembrane protease serine 2 (TMPRSS2), and furin and showed that ACE2 and TMPRSS2 are expressed in the trophoblast rather than in other placental villous cells. While furin is expressed in the main placental villous cell types, we surveyed, trophoblasts exhibit the highest expression. In line with the expression of these entry factors, we demonstrated that a SARS-CoV-2 pseudovirus could enter primary human trophoblasts. Mechanisms underlying placental defense against SARS-CoV-2 infection likely involve postentry processing, which may be germane for mitigating interventions against SARS-CoV-2.

IMPORTANCE Pregnant women worldwide have been affected by COVID-19. As the virus is commonly spread to various organs via the bloodstream and because human placental trophoblasts are directly bathed in maternal blood, feto-placental infection by SARS-CoV-2 seems likely. However, despite the heightened risk to pregnant women, thus far the transmission risk of COVID-19 to the feto-placental unit seems extremely low. This has been recently attributed to a negligible expression of SARS-CoV-2 entry factors in the human placenta. We therefore sought to explore the expression of the entry factors ACE2 and TMPRSS2 in the different cell types of human placental villi. Using a combination of transcriptome sequencing (RNA-seq), real-time quantitative PCR (RT-qPCR), in situ hybridization, and immunofluorescence, we found that trophoblasts, but not the other main villous cell types, express ACE2 and TMPRSS2, with a broad expression of furin. Correspondingly, we also showed that primary human trophoblasts are permissive to entry of SARS-CoV-2 pseudovirus particles.

Maternal and perinatal outcomes and placental pathologic examination of 29 SARS-CoV-2 infected patients in the third trimester of gestation

AIM

On December 31, 2019, an unknown outbreak of pulmonary disease was reported in China. The novel coronavirus SARS-CoV-2 was the etiologic agent of this disease, and responsible of the current pandemic of COVID-19. Accumulated evidence on placental features is based most on case-reports and small case-series, with differing results.

METHODS

We gathered a cohort of 29 infected pregnant mothers who delivered 32 newborns, and had placentas available for pathologic examination. Placentas were compared with a control group.

RESULTS

Of the 29 mothers, clinical and radiological features were similar to what was already described in COVID-19. Pregnancy modified some analytical parameters. One of the mothers succumbed to the disease. Of the 32 newborns, 1 developed an early infection, with positive reverse-transcriptase polymerase chain reaction (RT-PCR) at 48 h of life, with an initial RT-PCR negative. SARS-CoV-2 presence was assessed on placental tissue with immunohistochemistry and RT-PCR, both were negative. All newborns had good clinical outcomes. No differences in morphological placental findings were found among both groups.

CONCLUSION

Lack of statistically significant differences among case and control groups suggest that placentas from SARS-CoV-2 infected mothers represent a cohort of normal placentas only submitted because of maternal SARS-CoV-2 status. To the best of our knowledge, no irrefutable cases of vertical transmission have been yet described. Other authors have failed to demonstrate presence of viral RNA in placental tissue. Accumulated knowledge suggests that if vertical transmission is possible, it is a rare event.

Maternal-Fetal Immune Responses in Pregnant Women Infected with SARS-CoV-2

Pregnant women are a high-risk population for severe/critical COVID-19 and mortality. However, the maternal-fetal immune responses initiated by SARS-CoV-2 infection, and whether this virus is detectable in the placenta, are still under investigation. Herein, we report that SARS-CoV-2 infection during pregnancy primarily induced specific maternal inflammatory responses in the circulation and at the maternal-fetal interface, the latter being governed by T cells and macrophages. SARS-CoV-2 infection during pregnancy was also associated with a cytokine response in the fetal circulation (i.e. umbilical cord blood) without compromising the cellular immune repertoire. Moreover, SARS-CoV-2 infection neither altered fetal cellular immune responses in the placenta nor induced elevated cord blood levels of IgM. Importantly, SARS-CoV-2 was not detected in the placental tissues, nor was the sterility of the placenta compromised by maternal viral infection. This study provides insight into the maternal-fetal immune responses triggered by SARS-CoV-2 and further emphasizes the rarity of placental infection.

Cesarean Section or Vaginal Delivery to Prevent Possible Vertical Transmission From a Pregnant Mother Confirmed With COVID-19 to a Neonate: A Systematic Review

Background: The impact of delivery mode on the infection rates of Coronavirus disease 2019 (COVID-19) in the newborn remains unknown. We aimed to summarize the existing literature on COVID-19 infection during pregnancy to evaluate which mode of delivery is better for preventing possible vertical transmission from a pregnant mother confirmed with COVID-19 to a neonate. Methods: We performed a comprehensive literature search of PubMed, Embase, Cochrane Library, Web of Science, Google Scholar, and the Chinese Biomedical Literature database (CBM) from 31 December 2019 to 18 June 2020. We applied no language restrictions. We screened abstracts for relevance, extracted data, and assessed the risk of bias in duplicate. We rated the certainty of evidence using the GRADE approach. The primary outcome was severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test positivity in neonates born to mothers with confirmed COVID-19 following different delivery modes. Secondary outcomes were neonatal deaths and maternal deaths. This study is registered with PROSPERO, CRD42020194049. Results: Sixty-eight observational studies meeting inclusion criteria were included in the current study, with no randomized controlled trials. In total, information on the mode of delivery, detailed neonatal outcomes, and SARS-CoV-2 status were available for 1,019 pregnant women and 1,035 neonates. Six hundred and eighteen (59.71%) neonates were born through cesarean section and 417(40.29%) through vaginal delivery. Probable congenital SARS-CoV-2 infections were reported in 34/1,035 (3.29%) neonates. Of babies born vaginally, 9/417 (2.16%) were tested positive compared with 25/618 (4.05%) born by cesarean. Of babies born vaginally, 0/417 (0.00%) neonatal deaths were reported compared with 6/618 (0.97%) born by cesarean. Of women who delivered vaginally, 1/416 (0.24%) maternal deaths were reported compared with 11/603 (1.82%) delivered by cesarean. Two women died before delivery. Sensitivity analyses and subgroup analyses showed similar findings. Conclusions: The rate of neonatal COVID-19 infection, neonatal deaths, and maternal deaths are no greater when the mother gave birth through vaginal delivery. Based on the evidence available, there is no sufficient evidence supporting that the cesarean section is better than vaginal delivery in preventing possible vertical transmission from a pregnant mother confirmed with COVID-19 to a neonate. The mode of birth should be individualized and based on disease severity and obstetric indications. Additional good-quality studies with comprehensive serial tests from multiple specimens are urgently needed. Study registration: PROSPERO CRD42020194049.

Generation COVID-19 - Should the foetus be worried?

Aim

The aim of this narrative review was to evaluate the risks, both direct and indirect, to the foetus from the COVID‐19 pandemic.

Methods

Direct and indirect risks were defined as (a) vertical infection (congenital or intrapartum), (b) maternal infection and its sequelae, and (c) sources of maternal stress during lockdown, including social isolation and altered healthcare provision.

Results

Early studies suggest that vertical viral transmission is low; however, there may be an important effect of maternal infection on foetal growth and development. The impact of various degrees of lockdown on prospective mothers’ health, habits and healthcare provision is of concern. In particular, increased maternal stress has been shown to have a significant effect on foetal brain development increasing the risk of mental health, and cognitive and behavioural disorders in later life.

Conclusion

From the evidence available to date, direct risks to the foetus from the SARS‐CoV‐2 virus are low. Indirect effects of the pandemic, particularly resulting from the effect of maternal stress on the developing brain, can have lifelong detrimental impacts for this generation of children.

The SARS-CoV-2 receptor, angiotensin-converting enzyme 2, is required for human endometrial stromal cell decidualization†

The coronavirus disease 2019 (COVID-19) first appeared in December 2019 and rapidly spread throughout the world. The SARS-CoV-2 virus enters the host cells by binding to the angiotensin-converting enzyme 2 (ACE2). Although much of the focus is on respiratory symptoms, recent reports suggest that SARS-CoV-2 can cause pregnancy complications such as pre-term birth and miscarriages; and women with COVID-19 have had maternal vascular malperfusion and decidual arteriopathy in their placentas. Here, we report that the ACE2 protein is expressed in both endometrial epithelial and stromal cells in the proliferative phase of the menstrual cycle, and the expression increases in stromal cells in the secretory phase. It was observed that the ACE2 mRNA and protein abundance increased during primary human endometrial stromal cell (HESC) decidualization. Furthermore, HESCs transfected with ACE2-targeting siRNA impaired the full decidualization response, as evidenced by a lack of morphology change and lower expression of the decidualization markers PRL and IGFBP1. Additionally, in mice during pregnancy, the ACE2 protein was expressed in the uterine epithelial cells, and stromal cells increased through day 6 of pregnancy. Finally, progesterone induced Ace2 mRNA expression in mouse uteri more than vehicle or estrogen. These data establish a role for ACE2 in endometrial physiology, suggesting that SARS-CoV-2 may be able to enter endometrial stromal cells and elicit pathological manifestations in women with COVID-19, including an increased risk of early pregnancy loss.

Cesarean Section or Vaginal Delivery to Prevent Possible Vertical Transmission From a Pregnant Mother Confirmed With COVID-19 to a Neonate: A Systematic Review

Background: The impact of delivery mode on the infection rates of Coronavirus disease 2019 (COVID-19) in the newborn remains unknown. We aimed to summarize the existing literature on COVID-19 infection during pregnancy to evaluate which mode of delivery is better for preventing possible vertical transmission from a pregnant mother confirmed with COVID-19 to a neonate. Methods: We performed a comprehensive literature search of PubMed, Embase, Cochrane Library, Web of Science, Google Scholar, and the Chinese Biomedical Literature database (CBM) from 31 December 2019 to 18 June 2020. We applied no language restrictions. We screened abstracts for relevance, extracted data, and assessed the risk of bias in duplicate. We rated the certainty of evidence using the GRADE approach. The primary outcome was severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test positivity in neonates born to mothers with confirmed COVID-19 following different delivery modes. Secondary outcomes were neonatal deaths and maternal deaths. This study is registered with PROSPERO, CRD42020194049. Results: Sixty-eight observational studies meeting inclusion criteria were included in the current study, with no randomized controlled trials. In total, information on the mode of delivery, detailed neonatal outcomes, and SARS-CoV-2 status were available for 1,019 pregnant women and 1,035 neonates. Six hundred and eighteen (59.71%) neonates were born through cesarean section and 417(40.29%) through vaginal delivery. Probable congenital SARS-CoV-2 infections were reported in 34/1,035 (3.29%) neonates. Of babies born vaginally, 9/417 (2.16%) were tested positive compared with 25/618 (4.05%) born by cesarean. Of babies born vaginally, 0/417 (0.00%) neonatal deaths were reported compared with 6/618 (0.97%) born by cesarean. Of women who delivered vaginally, 1/416 (0.24%) maternal deaths were reported compared with 11/603 (1.82%) delivered by cesarean. Two women died before delivery. Sensitivity analyses and subgroup analyses showed similar findings. Conclusions: The rate of neonatal COVID-19 infection, neonatal deaths, and maternal deaths are no greater when the mother gave birth through vaginal delivery. Based on the evidence available, there is no sufficient evidence supporting that the cesarean section is better than vaginal delivery in preventing possible vertical transmission from a pregnant mother confirmed with COVID-19 to a neonate. The mode of birth should be individualized and based on disease severity and obstetric indications. Additional good-quality studies with comprehensive serial tests from multiple specimens are urgently needed. Study registration: PROSPERO CRD42020194049.

COVID-19 and pregnancy: are they friends or enemies?

OBJECTIVES

Novel coronavirus disease (COVID-19) is rapidly spreading all over the world. Although in many cases the infection causes very weak symptoms, it can be severe in patient with diverse chronical diseases and immunological compromising patients. Pregnancy is a unique condition in which mother and fetus peacefully collaborate. Diverse endocrine-immune mechanisms, mostly under progesterone control work together to protect the fetus from maternal immunocompetent cell activation driven rejection. The physiological shift to Th2 dominant environment, while favourable for fetus, it makes mothers susceptible to infective pathogens, making pregnancy during COVID-19 pandemic challenging.

MATERIALS AND METHODS

Studies involving COVID-19 in pregnancy and those analysing changes of immune system induced by COVID-19 were searched in databases such as PubMed, Scopus, Google Scholar and ScienceDirect. Databases were searched using a keyword COVID-19/coronavirus, that was combined with following terms: immune system, pregnancy, oestrogen, or progesterone. Search included studies published up to 01.07.2020. Almost 1,500 articles were found, but only 18 met criteria.

RESULTS

Most frequent symptoms of COVID-19 in mothers infected in the late pregnancy were fever and cough accompanied with lymphopenia and elevated C-reactive protein. Mothers reported to have severe disease had comorbidities and were obese. Low rate of neonatal complications of maternal Sars-Coc-2 infection without neonatal mortality was observed.

CONCLUSIONS

Currently available data didn't show significant relationship between COVID-19 severity and pregnancy and there is no strong evidence that mother's infection can lead to adverse pregnancy outcome, but further studies are needed to determinate the possible effects of COVID-19 gained during earlier pregnancy.

Maternal mortality by COVID-19 in Brazil

Abstract SARS-CoV-2, the new coronavirus of severe acute respiratory syndrome, which causes a predominantly respiratory disease called COVID-19, quickly caused a pandemic, due to its high transmissibility, leaving a trail of deaths around the world. Initially, the pregnancy puerperal cycle was not associated with complications and mortality, only later was recognized as a risk group. As the disease progressed, the maternal mortality rate by COVID-19 increased, Brazil is responsible for an important portion. This rate may be even higher due to underreporting, difficulties in performing laboratorial tests and possible false negative results and depends on the health policies adopted by each region or country. It is important to carry out studies on maternal mortality so that the prognostic factors can be recognized and so avoid them.