Infectious causes of stillbirth: a clinical perspective

Association of common maternal infections with birth outcomes: a multinational cohort study

PURPOSE

It is unclear whether common maternal infections during pregnancy are risk factors for adverse birth outcomes. We assessed the association between self-reported infections during pregnancy with preterm birth and small-for-gestational-age (SGA) in an international cohort consortium.

METHODS

Data on 120,507 pregnant women were obtained from six population-based birth cohorts in Australia, Denmark, Israel, Norway, the UK and the USA. Self-reported common infections during pregnancy included influenza-like illness, common cold, any respiratory tract infection, vaginal thrush, vaginal infections, cystitis, urinary tract infection, and the symptoms fever and diarrhoea. Birth outcomes included preterm birth, low birth weight and SGA. Associations between maternal infections and birth outcomes were first assessed using Poisson regression in each cohort and then pooled using random-effect meta-analysis. Risk ratios (RR) and 95% confidence intervals (CI) were calculated, adjusted for potential confounders.

RESULTS

Vaginal infections (pooled RR, 1.10; 95% CI, 1.02-1.20) and urinary tract infections (pooled RR, 1.17; 95% CI, 1.09-1.26) during pregnancy were associated with higher risk of preterm birth. Similar associations with low birth weight were also observed for these two infections. Fever during pregnancy was associated with higher risk of SGA (pooled RR, 1.07; 95% CI, 1.02-1.12). No other significant associations were observed between maternal infections/symptoms and birth outcomes.

CONCLUSION

Vaginal infections and urinary infections during pregnancy were associated with a small increased risk of preterm birth and low birth weight, whereas fever was associated with SGA. These findings require confirmation in future studies with laboratory-confirmed infection diagnosis.

Health of singleton neonates in Switzerland through time and crises: a cross-sectional study at the population level, 2007-2022

BACKGROUND

Being exposed to crises during pregnancy can affect maternal health through stress exposure, which can in return impact neonatal health. We investigated temporal trends in neonatal outcomes in Switzerland between 2007 and 2022 and their variations depending on exposure to the economic crisis of 2008, the flu pandemic of 2009, heatwaves (2015 and 2018) and the COVID-19 pandemic.

METHODS

Using individual cross-sectional data encompassing all births occurring in Switzerland at the monthly level (2007-2022), we analysed changes in birth weight and in the rates of preterm birth (PTB) and stillbirth through time with generalized additive models. We assessed whether the intensity or length of crisis exposure was associated with variations in these outcomes. Furthermore, we explored effects of exposure depending on trimesters of pregnancy.

RESULTS

Over 1.2 million singleton births were included in our analyses. While birth weight and the rate of stillbirth have remained stable since 2007, the rate of PTB has declined by one percentage point. Exposure to the crises led to different results, but effect sizes were overall small. Exposure to COVID-19, irrespective of the pregnancy trimester, was associated with a higher birth weight (+12 grams [95% confidence interval (CI) 5.5 to 17.9 grams]). Being exposed to COVID-19 during the last trimester was associated with an increased risk of stillbirth (odds ratio 1.24 [95%CI 1.02 to 1.50]). Exposure to the 2008 economic crisis during pregnancy was not associated with any changes in neonatal health outcomes, while heatwave effect was difficult to interpret.

CONCLUSION

Overall, maternal and neonatal health demonstrated resilience to the economic crisis and to the COVID-19 pandemic in a high-income country like Switzerland. However, the effect of exposure to the COVID-19 pandemic is dual, and the negative impact of maternal infection on pregnancy is well-documented. Stress exposure and economic constraint may also have had adverse effects among the most vulnerable subgroups of Switzerland. To investigate better the impact of heatwave exposure on neonatal health, weekly or daily-level data is needed, instead of monthly-level data.

Placental Lesions Associated With Stillbirth by Gestational Age, as Related to Cause of Death: Follow-Up Results From the Stillbirth Collaborative Research Network

BACKGROUND

We previously identified placental lesions associated with stillbirths of varying gestational ages (GA) using advanced feature analysis. We further investigated the relationships between placental lesions and cause of death in stillbirths within these GA ranges.

METHODS

Using data from the Stillbirth Collaborative Research Network, we derived a sample of stillbirths who underwent placental examination and Initial Causes of Fetal Death (INCODE) evaluation for determining cause of death. We then compared the rates of causes of death within and among GA ranges (extreme preterm stillbirth [PTSB] [<28 weeks], early PTSB [28-336/7 weeks], late PTSB [34-366/7 weeks], term stillbirth [≥37 weeks]) according to the presence of these lesions.

RESULTS

We evaluated 352 stillbirths. In extreme PTSB, obstetric complications and infections were associated with acute funisitis. In early PTSB, uteroplacental insufficiency was associated with parenchymal infarcts. In term stillbirth (vs early PTSB), increased syncytial knots were associated with umbilical cord causes and infection.

CONCLUSIONS

Placental lesions of high importance in distinguishing stillbirths at different GAs are associated with specific causes of death. This information is important in relating the presence of placental lesions and fetal death and in helping to understand etiologies of stillbirths at different GAs.

Pregnancy, infection, and epigenetic regulation: A complex scenario

A unique immunological condition, pregnancy ensures fetus from maternal rejection, allows adequate fetal development, and protects against microorganisms. Infections during pregnancy may lead to devastating consequences for pregnant women and fetuses, resulting in the mother's death, miscarriage, premature childbirth, or neonate with congenital infection and severe diseases and defects. Epigenetic (heritable changes in gene expression) mechanisms like DNA methylation, chromatin modification, and gene expression modulation during gestation are linked with the number of defects in the fetus and adolescents. The feto-maternal crosstalk for fetal survival during the entire gestational stages are tightly regulated by various cellular pathways, including epigenetic mechanisms that respond to both internal as well outer environmental factors, which can influence the fetal development across the gestational stages. Due to the intense physiological, endocrinological, and immunological changes, pregnant women are more susceptible to bacterial, viral, parasitic, and fungal infections than the general population. Microbial infections with viruses (LCMV, SARS-CoV, MERS-CoV, and SARS-CoV-2) and bacteria (Clostridium perfringens, Coxiella burnetii, Listeria monocytogenes, Salmonella enteritidis) further increase the risk to maternal and fetal life and developmental outcome. If the infections remain untreated, the possibility of maternal and fetal death exists. This article focused on the severity and susceptibility to infections caused by Salmonella, Listeria, LCMV, and SARS-CoV-2 during pregnancy and their impact on maternal health and the fetus. How epigenetic regulation during pregnancy plays a vital role in deciding the fetus's developmental outcome under various conditions, including infection and other stress. A better understanding of the host-pathogen interaction, the characterization of the maternal immune system, and the epigenetic regulations during pregnancy may help protect the mother and fetus from infection-mediated outcomes.

Placental lesions associated with stillbirth by gestational age, according to feature importance: Results from the stillbirth collaborative research network

INTRODUCTION

Previous studies have identified lesions commonly found in placentas associated with stillbirth but have not distinguished across a range of gestational ages (GAs). The objective of this study was to identify lesions associated with stillbirths at different GAs by adapting methods from the chemical machine learning field to assign lesion importance based on correlation with GA.

METHODS

Placentas from the Stillbirth Collaborative Research Network were examined according to standard protocols. GAs at stillbirth were categorized as: <28 weeks (extreme preterm stillbirth [PTSB]), 28-33'6 weeks (early PTSB), 34-36'6 weeks (late PTSB), ≥37 weeks (term stillbirth). We identified and ranked the most discriminating placental features, as well as those that were similar across GA ranges, using Kernel Principal Covariates Regression (KPCovR).

RESULTS

These analyses included 210 (47.2%) extreme PTSB, 85 (19.1%) early PTSB, 62 (13.9%) late PTSB, and 88 (19.8%) term stillbirths. When we compute the KPCovR, the first principal covariate indicates that there are four lesions (acute funisitis & nucleated fetal red blood cells found in extreme PTSB; multifocal reactive amniocytes & multifocal meconium found in term stillbirth) that distinguish GA ranges among all stillbirths.

DISCUSSION

There are distinct placental lesions present across GA ranges in stillbirths; these lesions are identifiable using sophisticated feature selection. Further investigation may identify histologic changes across gestations that relate to fetal mortality.

Is there a placental microbiota? A critical review and re-analysis of published placental microbiota datasets

The existence of a placental microbiota is debated. The human placenta has historically been considered sterile and microbial colonization was associated with adverse pregnancy outcomes. Yet, recent DNA sequencing investigations reported a microbiota in typical human term placentas. However, this detected microbiota could represent background DNA or delivery-associated contamination. Using fifteen publicly available 16S rRNA gene datasets, existing data were uniformly re-analyzed with DADA2 to maximize comparability. While Amplicon Sequence Variants (ASVs) identified as Lactobacillus, a typical vaginal bacterium, were highly abundant and prevalent across studies, this prevalence disappeared after applying likely  DNA contaminant removal to placentas from term cesarean deliveries. A six-study sub-analysis targeting the 16S rRNA gene V4 hypervariable region demonstrated that bacterial profiles of placental samples and technical controls share principal bacterial ASVs and that placental samples clustered primarily by study origin and mode of delivery. Contemporary DNA-based evidence does not support the existence of a placental microbiota.ImportanceEarly-gestational microbial influences on human development are unclear. By applying DNA sequencing technologies to placental tissue, bacterial DNA signals were observed, leading some to conclude that a live bacterial placental microbiome exists in typical term pregnancy. However, the low-biomass nature of the proposed microbiome and high sensitivity of current DNA sequencing technologies indicate that the signal may alternatively derive from environmental or delivery-associated bacterial DNA contamination. Here we address these alternatives with a re-analysis of 16S rRNA gene sequencing data from 15 publicly available placental datasets. After identical DADA2 pipeline processing of the raw data, subanalyses were performed to control for mode of delivery and environmental DNA contamination. Both environment and mode of delivery profoundly influenced the bacterial DNA signal from term-delivered placentas. Aside from these contamination-associated signals, consistency was lacking across studies. Thus, placentas delivered at term are unlikely to be the original source of observed bacterial DNA signals.

Timing of perinatal death; causes, circumstances, and regional variations among reviewed deaths in Ethiopia

INTRODUCTION

Ethiopia is one of the countries facing a very high burden of perinatal death in the world. Despite taking several measures to reduce the burden of stillbirth, the pace of decline was not that satisfactory. Although limited perinatal mortality studies were conducted at a national level, none of the studies stressed the timing of perinatal death. Thus, this study is aimed at determining the magnitude and risk factors that are associated with the timing of perinatal death in Ethiopia.

METHODS

National perinatal death surveillance data were used in the study. A total of 3814 reviewed perinatal deaths were included in the study. Multilevel multinomial analysis was employed to examine factors associated with the timing of perinatal death in Ethiopia. The final model was reported through the adjusted relative risk ratio with its 95% Confidence Interval, and variables with a p-value less than 0.05 were declared statistically significant predictors of the timing of perinatal death. Finally, a multi-group analysis was carried out to observe inter-regional variation among selected predictors.

RESULT

Among the reviewed perinatal deaths, 62.8% occurred during the neonatal period followed by intrapartum stillbirth, unknown time of stillbirth, and antepartum stillbirth, each contributing 17.5%,14.3%, and 5.4% of perinatal deaths, respectively. Maternal age, place of delivery, maternal health condition, antennal visit, maternal education, cause of death (infection and congenital and chromosomal abnormalities), and delay to decide to seek care were individual-level factors significantly associated with the timing of perinatal death. While delay reaching a health facility, delay to receive optimal care health facility, type of health facility and type region were provincial-level factors correlated with the timing of perinatal death. A statistically significant inter-regional variation was observed due to infection and congenital anomalies in determining the timing of perinatal death.

CONCLUSION

Six out of ten perinatal deaths occurred during the neonatal period, and the timing of perinatal death was determined by neonatal, maternal, and facility factors. As a way forward, a concerted effort is needed to improve the community awareness of institutional delivery and ANC visit. Moreover, strengthening the facility level readiness in availing quality service through all paths of the continuum of care with special attention to the lower-level facilities and selected poor-performing regions is mandatory.

Trend and risk factors of fatal pregnancy termination: A long-term nationwide population-based cross-section survey in Bangladesh

BACKGROUND

Pregnant women often experience the fatal outcome of their pregnancy both in developed and impoverished countries. Due to strong health systems and services, factual and historical data are available from developed countries. However, the prevalence trend and risk factors of a fatal termination of pregnancy in developing countries like Bangladesh are still lacking.

OBJECTIVE

The objective of the current study was to determine the 20 years trend of prevalence and risk factors of fatal pregnancy termination from 1997 to 2018 in Bangladesh.

METHOD

This study utilised the publicly available seven consecutive cross-data on Bangladesh Demographic and Health Surveys data since 1997 following identical methods among women of reproductive age. Respondent was asked if they had had a fatal pregnancy termination ever. A Generalised Linear model with a log-Poisson link was used to estimate the relative risk of different predictors for four survey time points (1998, 2004, 2011, 2018).

RESULTS

The proportions of fatal pregnancy termination in urban and rural areas were 24% vs. 19% and 24% vs. 22% in 1997 and 2018, respectively. In multivariable analysis, maternal age 30 years and above and obesity were strongly associated in all survey time points. The richest wealth index had a weak association in 1997 but was strongly associated in 2011 and 2018. A significant modest association with secondary complete education level was only observed in 2018.

CONCLUSION

The overall proportions of fatal pregnancy termination in Bangladesh remain nearly static; however, its risk factors differed across different survey time points.

Microbial Analysis of Umbilical Cord Blood Reveals Novel Pathogens Associated with Stillbirth and Early Preterm Birth

Stillbirths account for half of all perinatal mortality, but the underlying cause of a significant portion of the cases remains unknown. We set out to test the potential role and extent of microbial infection in stillbirth through a case-control analysis of fetal cord blood collected from the multisite Stillbirth Collaborative Research Network. Cases (n = 60) were defined as stillbirths at >20 weeks of gestation, and controls (n = 176) were live births. The bacterial presence, abundance, and composition were analyzed by endpoint PCR of full-length 16S rRNA and the V4 amplicon sequence variants (ASVs). The results demonstrate that bacterial prevalence and abundance were both significantly increased in stillbirth, even after adjusting for maternal age, race, body mass index, number of pregnancies, gestational age, and multiple gestations. Composition of bacterial communities in the cord blood also differed significantly. Using a group of 25 ASVs differentially abundant between the two groups, a Random Forest classification model achieved an accuracy score of 0.76 differentiating stillbirth and live birth, with Group B Streptococcus as the most enriched species in stillbirth. Positive PCR was also significantly associated with early preterm birth. A group of oral anaerobes, including Actinomyces, Campylobacter, Fusobacterium, Peptostreptococcus, Porphyromonas, and Prevotella, were enriched in live early preterm birth, suggesting possible oral origin of infection. Our ASV-based microbiome analysis revealed specific candidate pathogens associated with infections in stillbirth and early preterm birth. The cord blood microbial signatures may be markers of adverse pregnancy outcomes. Our study will help identify possible mechanism of infection and improve our ability to prevent stillbirth and early preterm birth.

Viral infections in stillbirth: a contribution underestimated in Mexico?

OBJECTIVES

To analyze the role of viral infections as etiology of stillbirths in Mexico and their epidemiological impact in the context of the global Every Newborn Initiative.

METHODS

A comprehensive literature search was performed in electronic databases related to stillbirth and viral infections published prior to January 19th 2021. Stillbirths records and causes from National Mexican databases, during 2008-2019 period were also computed.

RESULTS

Only two articles with a direct relationship between viral infection and stillbirth were found, and one article with an indirect serological association was identified. During the analyzed period there were 198,076 stillbirths, with a National stillbirth rate (SBR) ranging from 6.9 to 6.5 between 2008 and 2014, with a subsequent increase to reach 7.7 in 2019. Only 19 cases were attributed to viral causes and a specific virus was identified in 11. The main causes of early stillbirth were a fetus with premature rupture of membranes and light for gestational age, and for late stillbirth these were fetus affected by oligohydramnios and slow fetal growth. The percentage classified as unspecified deaths varied from 34.4-41.9%.

CONCLUSIONS

In Mexico, there has been an increase in SBR during last years, but the goals of the Every Newborn Initiative is met. More than 14,500 stillbirths with at least 5,100 unspecified cases have been reported per year, and only 11 cases were attributable to a specific virus, highlighting the serious underestimation of cases and the need of implementation of routine viral diagnosis methods to improve the care of this global health problem.

Altered Offspring Immunity in Maternal Parasitic Infections

Maternal infection during pregnancy is known to alter the development and function of offspring's immune system, leading to inappropriate immune responses to common childhood infections and immunizations. Although this is an expanding field, maternal parasitic infections remain understudied. Millions of women of reproductive age are currently at risk for parasitic infection, whereas many pregnant, chronically infected women are excluded from mass drug administration due partially to a lack of resources, as well as fear of unknown adverse fetal developmental outcomes. In areas endemic for multiple parasitic infections, such as sub-Saharan Africa, there are increased rates of morbidity and mortality for various infections during early childhood in comparison with nonendemic areas. Despite evidence supporting similar immunomodulatory effects between various parasite species, there is no clear mechanistic understanding of how maternal infection reprograms offspring immunity. This brief review will compare the effects of selected maternal parasitic infections on offspring immunity.

Global incidence and mortality of neonatal sepsis: a systematic review and meta-analysis

BACKGROUND

Neonates are at major risk of sepsis, but data on neonatal sepsis incidence are scarce. We aimed to assess the incidence and mortality of neonatal sepsis worldwide.

METHODS

We performed a systematic review and meta-analysis. 13 databases were searched for the period January 1979-May 2019, updating the search of a previous systematic review and extending it in order to increase data inputs from low-income and middle-income countries (LMICs). We included studies on the population-level neonatal sepsis incidence that used a clinical sepsis definition, such as the 2005 consensus definition, or relevant ICD codes. We performed a random-effects meta-analysis on neonatal sepsis incidence and mortality, stratified according to sepsis onset, birth weight, prematurity, study setting, WHO region and World Bank income level.

RESULTS

The search yielded 4737 publications, of which 26 were included. They accounted for 2 797 879 live births and 29 608 sepsis cases in 14 countries, most of which were middle-income countries. Random-effects estimator for neonatal sepsis incidence in the overall time frame was 2824 (95% CI 1892 to 4194) cases per 100 000 live births, of which an estimated 17.6% 9 (95% CI 10.3% to 28.6%) died. In the last decade (2009-2018), the incidence was 3930 (95% CI 1937 to 7812) per 100 000 live births based on four studies from LMICs. In the overall time frame, estimated incidence and mortality was higher in early-onset than late-onset neonatal sepsis cases. There was substantial between-study heterogeneity in all analyses. Studies were at moderate to high risk of bias.

CONCLUSION

Neonatal sepsis is common and often fatal. Its incidence remains unknown in most countries and existing studies show marked heterogeneity, indicating the need to increase the number of epidemiological studies, harmonise neonatal sepsis definitions and improve the quality of research in this field. This can help to design and implement targeted interventions, which are urgently needed to reduce the high incidence of neonatal sepsis worldwide.

A comparative study to assess risk of oral candidiasis in pregnant and nonpregnant women

Background:

The major hormonal changes observed in pregnant women lead to an imbalance in the oral environment. Hence, recent studies suggest that the placenta may harbor a unique microbiome that may have originated in the maternal oral microbiome.

Aim:

The present study aimed to assess the risk factor of oral candidiasis in pregnancy and to evaluate the prevalence of Candida species in the oral cavity of pregnant women in all three trimesters. The comparison was also done between pregnant and nonpregnant women to evaluate the cause of the prevalence of candidal species.

Materials and Methods:

Thirty pregnant and thirty nonpregnant women aged between 20 and 30 years were included in the study that were healthy and who did not have any obvious lesion in the oral cavity. The sterile swabs were used to collect samples from the oral cavity from both the groups by brushing the dorsum of the tongue and buccal mucosa. The pregnant women were followed throughout the pregnancy, i.e., in every trimester, for the sample collection. The samples were then cultured on Sabouraud Dextrose Agar media. The positive growth on culture plates was then inoculated on HiCrome agar differential agar media for speciation.

Results:

Statistical analysis was done by comparing the positive growth in pregnant and nonpregnant women using Fisher's exact test. The pregnant women were compared in three trimesters using the McNemar Chi-square test.

Conclusion:

The study concludes that there was no significant presence of Candidal species when compared between pregnant and nonpregnant groups. The prevalence of Candida species also remained the same.

Increased homocysteine mediated oxidative stress as key determinant of hepatitis E virus (HEV) infected pregnancy complication and outcome: A study from Northeast India

With the background of association of oxidative stress and Hepatitis E virus (HEV) infection in pregnancy complications the present novel study aimed to evaluate the significance of changes in maternal homocysteine levels and the related mechanism(s) in the pathophysiology of HEV related pregnancy complications and negative outcomes. Term delivery (TD, N = 194) and HEV-IgM positive pregnancy cases [N = 109] were enrolled. Serum and placental homocysteine levels were evaluated by ELISA and immunofluorescence and in turn correlated with serum Vitamin B12 levels. Distribution of variant MTHFR C➔T and TYMS1494del6bp genotyping were studied by PCR-RFLP. Differential folate receptor alpha (FR-α) expression in placenta was evaluated by real-time PCR and immunofluorescence respectively. The HEV viral load was significantly higher in both FHF and AVH cases. Higher serum homocysteine levels was associated with preterm delivery (PTD) and fetal death in HEV infected cases and was significantly inversely correlated with serum VitaminB12 levels in HEV cases. Placental homocysteine expression was upregulated in HEV cases, and in cases with negative pregnancy outcome. A Homocysteine level was associated with MTHFR C677T status. Genetic alterations in folate pathway was associated with increased risk of PTD in HEV infected pregnancy cases, disease severity, and negative pregnancy outcome in AVH and FHF groups. FR-α expression was downregulated in placental tissues of HEV infected pregnancy.Placental stress caused by HEV inflicted increased homocysteine due to alterations in maternal vitamin B12 levels and folate pathway components is detrimental mechanism in PTD and negative pregnancy outcome in HEV infected pregnancy cases and holds prognostic and therapeutic significance.

Gross and histological findings in the canine placenta and amnion at term: What's normal, abnormal or pathological?

The canine placenta is an underexamined organ. Placental abnormalities can affect foetus development and may be responsible for a low weight of the infant at birth; however, knowledge on their clinical significance in the canine species is limited. We aimed to describe macroscopic and microscopic findings in the canine placenta and amnion at term in clinically uncomplicated pregnancies and to evaluate their relationship with birth weight of healthy puppies. During natural delivery or C-section, the birth weight of 82 puppies was recorded, 72 placentas and 66 amnions were recovered. The foetal and maternal surfaces of the placental girdle, marginal haematoma and amnion were evaluated. Each gross finding was recorded, morphometrically assessed and sampled for histological diagnosis. Furthermore, specimens of placenta and amnion were collected from representative areas and microscopic deviations from normal structure were evaluated in haematoxylin and eosin sections. Gross examination revealed 'abnormalities' in the 75.4% of the collected placentas. Necrosis was the gross change most commonly observed in the placental girdle (72.5%). Congestion (17.4%) and clotted blood/fibrinoid material (2.9%) were also observed. No gross changes of either the marginal haematoma or the amnion were recorded. Histologically, placental girdle showed necrosis (62.3%), mineralization (52.2%), congestion (36.2%) and neutrophilic infiltration (27.5%). Marginal haematoma exhibited mineralization (11.6%) and neutrophils (29%), while necrotic foci were rarely observed (4.3%). In the amnion, the most frequent alteration observed was hypertrophy of the epithelium (35.9%) followed by oedema (31.2%), mineralized foci (28.1%), fibrosis (23.4%), congestion (15.6%) and more rarely neutrophils (12.5%). Puppies' birth weight was not statistically affected by either gross or histological abnormalities. Our study revealed that macroscopic and microscopic 'abnormalities' of the placenta and amnion may be common in uncomplicated pregnancies at term; however, no implications on puppies' birth weight were observed. Deviations from 'normal' morphology of canine foetal adnexa warrant further investigation to assess their clinical implications if present.

Macrophage Plasticity in Reproduction and Environmental Influences on Their Function

Macrophages are key components of the innate immune system and exhibit extensive plasticity and heterogeneity. They play a significant role in the non-pregnant cycling uterus and throughout gestation they contribute to various processes underpinning reproductive success including implantation, placentation and parturition. Macrophages are also present in breast milk and impart immunomodulatory benefits to the infant. For a healthy pregnancy, the maternal immune system must adapt to prevent fetal rejection and support development of the semi-allogenic fetus without compromising host defense. These functions are dependent on macrophage polarization which is governed by the local tissue microenvironmental milieu. Disruption of this microenvironment, possibly by environmental factors of infectious and non-infectious origin, can affect macrophage phenotype and function and is linked to adverse obstetric outcomes, e.g. spontaneous miscarriage and preterm birth. Determining environmental influences on cellular and molecular mechanisms that control macrophage polarization at the maternal-fetal interface and the role of this in pregnancy complications could support approaches to alleviating adverse pregnancy outcomes.

Immunological Profile and Bacterial Drug Resistance in Pregnant Women: A Cross Sectional Study

Objectives

This study aimed to investigate the immunological and bacterial profiles in pregnant women of Bafang-Cameroon.

Methods

Stool and midstream urine were cultured using specific culture media. The disk diffusion method was used for the antimicrobial susceptibility test. T-cell lymphocyte counts (CD3, CD4 and CD8), white blood cell counts, sensitive C-reactive protein, and interleukin-6, were measured by flow cytometry, optical detection, and the enzyme-linked immunosorbent assay solid phase direct sandwich method.

Results

Out of 700 participants, 71.43% were pregnant, and 28.57% were non-pregnant women. The mean age was 29.40 ± 8.27 and 27.41 ± 6.55 years in non-pregnant and pregnant women, respectively. CD4 T-cells were not significantly lower in pregnant women compared with non-pregnant women. There were 43.65% and 56.35% bacteria isolates obtained from urine and stool samples, respectively. Bacteria were mostly isolated in patients with a CD4 T-cell count between 461 and 806 cells/μL. Isolates of Klebsiella pneumoniae and Enterobacter aerogenes showed 100% resistance in non-pregnant women, however all isolated bacteria were shown to be multidrug resistant in pregnant women. Salmonella sp. (24.3%) and Escherichia coli (21.51%) showed an increase in multidrug resistant phenotypes in pregnant women.

Conclusion

This study demonstrated that routine bacteriological analysis during pregnancy is necessary for their follow-up care.

Maternal- and Fetal-Encoded Perforin-2 Limits Placental Infection by a Bloodborne Pathogen

Placental immune responses are highly regulated to strike a balance between protection and tolerance. For relatively mild infections, protection encompasses both the mother and fetus; however, during worsening conditions, protection becomes exclusively reserved for the mother. Previously, we and others have shown that the host factor perforin-2 plays a central role in protecting mice and cells against infection. In this study, we analyzed perforin-2 activity in the mouse placenta to determine whether perforin-2 plays a similarly protective role. We show that perforin-2 is critical for inhibiting Listeria monocytogenes colonization of the placenta and fetus and that this protection is due to both maternal and fetal-encoded perforin-2. Perforin-2 mRNA is readily detectable in individual immune cells of the decidua, and these levels are further enhanced specifically in decidual macrophages during high-dose infections that result in fetal expulsion. Unexpectedly, inductive perforin-2 expression in decidual macrophages did not occur during milder infections in which fetal viability remained intact. This pattern of expression significantly differed from that observed in splenic macrophages in which inductive perforin-2 expression was observed in both high and mild infection conditions. In the placenta, inductive perforin-2 expression in decidual macrophages was coincident with their polarization from a CD206⁺ MHC class II^lo to CD206^- MHC class II^hi phenotype that normally occurs in the placenta during high-burden infections. Our results suggest that perforin-2 is part of a host response that is protective either for both the mother and fetus in milder infections or exclusively for the mother during high-dose infections.

The immune system and microbiome in pregnancy

Hormonal changes during pregnancy instigate numerous physiological changes aimed at the growth and delivery of a healthy baby. A careful balance between immunological tolerance against fetal antigens and immunity against infectious agents needs to be maintained. A three-way interaction between pregnancy hormones, the immune system and our microbiota is now emerging. Recent evidence suggests that microbial alterations seen during pregnancy may help maintain homeostasis and aid the required physiological changes occurring in pregnancy. However, these same immunological and microbial alterations may also make women more vulnerable during pregnancy and the post-partum period, especially regarding immunological and infectious diseases. Thus, a further understanding of the host-microbial interactions taking place during pregnancy may improve identification of populations at risk for adverse pregnancy outcomes.

Microbiota in vaginal health and pathogenesis of recurrent vulvovaginal infections: a critical review

Recurrent vulvovaginal infections (RVVI) has not only become an epidemiological and clinical problem but also include large social and psychological consequences. Understanding the mechanisms of both commensalism and pathogenesis are necessary for the development of efficient diagnosis and treatment strategies for these enigmatic vaginal infections. Through this review, an attempt has been made to analyze vaginal microbiota (VMB) from scratch and to provide an update on its current understanding in relation to health and common RVVI i.e. bacterial vaginosis, vulvovaginal candidiaisis and Trichomoniasis, making the present review first of its kind. For this, potentially relevant studies were retrieved from data sources and critical analysis of the literature was made. Though, culture-independent methods have greatly unfolded the mystery regarding vaginal bacterial microbiome, there are only a few studies regarding the composition and diversity of vaginal mycobiome and different Trichomonas vaginalis strains. This scenario suggests a need of further studies based on comparative genomics of RVVI pathogens to improve our perceptive of RVVI pathogenesis that is still not clear (Fig. 5). Besides this, the review details the rationale for Lactobacilli dominance and changes that occur in healthy VMB throughout a women's life. Moreover, the list of possible agents continues to expand and new species recognised in both health and VVI are updated in this review. The review concludes with the controversies challenging the widely accepted dogma i.e. "VMB dominated with Lactobacilli is healthier than a diverse VMB". These controversies, over the past decade, have complicated the definition of vaginal health and vaginal infections with no definite conclusion. Thus, further studies on newly recognised microbial agents may reveal answers to these controversies. Conversely, VMB of women could be an answer but it is not enough to just look at the microbiology. We have to look at the woman itself, as VMB which is fine for one woman may be troublesome for others. These differences in women's response to the same VMB may be determined by a permutation of behavioural, cultural, genetic and various other anonymous factors, exploration of which may lead to proper definition of vaginal health and disease.

Placental Abnormalities Associated With Childbirth

Pathologists are faced with a variety of problems when considering placental tissue in cases of stillbirth. It is recognized that there are changes which occur following fetal demise and which can complicate the assessment and may coexist with other morphological changes. It is recognized that up to 25% of stillbirths may have a recognizable abnormality causing fetal demise. A systematic review of placental tissue allows many of these disorders to be identified. This review considers macroscopic and microscopic features of placental pathology in stillbirth together with clinicopathological correlation. Stillbirth definitions, general aspects of macroscopic assessment of placentas, placental changes after fetal demise, and some recognizable causes of fetal demise are considered.

Criteria for assigning cause of death for stillbirths and neonatal deaths in research studies in low-middle income countries

Accurate knowledge regarding cause of death (COD) for stillbirths and neonatal deaths is crucial, especially in low-income countries, in order for public health and medical officials to choose appropriate interventions likely to reduce these deaths. To date, many of the COD studies in these areas have relied only on obstetric or neonatal clinical information and the determination of COD is likely to be inaccurate. Information related to infectious COD is especially lacking. Thus, without more sophisticated testing, data as currently collected only provide a very weak approximation of the COD and may well lead to adoption of interventions of limited usefulness. In this commentary, we propose recommendations regarding the type of data needed to determine with reasonable accuracy the COD for stillbirths and neonatal deaths in low-resource settings. Using these data, and a method to determine the degree of certainty, we then propose definitions for the most common COD. Our goal is to reduce subjectivity and provide more specificity for the tests used in existing classification systems so that the methodology of COD determination is transparent and able to be replicated over time and from location to location.

Fetal and Placental Pathology in Congenital Syphilis: A Comprehensive Study in Perinatal Autopsy

INTRODUCTION

At autopsy, without available serologic information, diagnosing congenital syphilis (CS) relies on identification of Treponema pallidum in tissues. Recognition of clues leading to detection of the organism is important.

MATERIALS AND METHODS

Autopsy cases with CS were studied for fetal and placental abnormalities.

RESULTS

Twenty-one cases were recruited: 12/21 with identifiable T. pallidum and 9/21 with positive serology and characteristics of CS. 20/21 (95%) demonstrated ≥1 fetal abnormalities. Chronic stress involution of thymus was most common. Hydrops and hepatosplenomegaly were found in >50%. Metaphyseal abnormalities and organ inflammation were found in <30%. Mucocutaneous lesions were lacking. Placental abnormalities were identified in 20/21 (95%). Placentomegaly was most common. Amniotic fluid infection (AFI) was noted in >50%.

CONCLUSION

Common findings in CS at autopsy include chronic stress involution of thymus, hydrops, and hepatosplenomegaly. Mucocutaneous lesions are uncommon. Common placental findings in fetal deaths due to CS include placentomegaly and AFI.

Symptomatic dengue infection during pregnancy and the risk of stillbirth in Brazil, 2006-12: a matched case-control study

BACKGROUND

Maternal infections during pregnancy can increase the risk of fetal death. Dengue infection is common, but little is known about its role in fetal mortality. We aimed to investigate the association between symptomatic dengue infection during pregnancy and fetal death.

METHODS

We did a nested case-control study using obstetrician-collected data from the Brazilian livebirth information system (SINASC), the mortality information system (SIM), and the national reportable disease information system (SINAN). We identified all pregnancies ending in stillbirth and a random sample of livebirths between Jan 1, 2006, and Dec 31, 2012. We did linkage to determine which mothers were diagnosed with dengue infection during pregnancy. By use of stillbirths as cases and a sample of matched livebirths as a control, we calculated matched odds ratios (mORs) using conditional logistic regression adjusted for maternal age and education.

FINDINGS

275 (0·2%) of 162 188 women who had stillbirths and 1507 (0·1%) of 1 586 105 women who had livebirths were diagnosed with dengue infection during pregnancy. Symptomatic dengue infection during pregnancy almost doubled the odds of fetal death (mOR 1·9, 95% CI 1·6-2·2). The increase in risk was similar when analyses were restricted to laboratory-confirmed cases of dengue infection (1·8, 1·4-2·4). Severe dengue infection increased the risk of fetal death by about five times (4·9, 2·3-10·2).

INTERPRETATION

Symptomatic dengue infection during pregnancy is associated with an increased risk of fetal death. We recommend further epidemiological and biological studies of the association between dengue and poor birth outcomes to measure the burden of subclinical infections and elucidate pathological mechanisms.

FUNDING

Brazilian National Council for Scientific and Technological Development, Horizon 2020.

Arboviruses and pregnancy: maternal, fetal, and neonatal effects

Arboviruses are an expanding public health threat, with pregnant women facing unique complications from arbovirus infections. These infections, such as dengue and Crimean-Congo haemorrhagic fever, can be more severe in pregnant women than in the general population. Vertical transmission is reported for many arboviruses and can severely affect pregnancy outcome. Indeed, arboviruses-particularly flaviviruses and alphaviruses-are associated with increased risks of fetal loss and premature birth. Arboviruses can be teratogenic, as is the case for Zika virus and Venezuelan equine encephalitis virus. Finally, intrapartum transmission can result in severe neonatal infections, as is true for chikungunya virus. Although the global burden of arboviruses is well recognised, few studies have provided data on arbovirus infection specifically in the context of maternal and child health. Epidemiological and clinical studies are therefore needed to better assess the burden of arbovirus infections during pregnancy and to improve the prevention and clinical management of these viral infections. In this Review, we analyse the information available and identify gaps in knowledge that require further assessment.

Perinatal death investigations: What is current practice?

Perinatal death (PD) is a devastating obstetric complication. Determination of cause of death helps in understanding why and how it occurs, and it is an indispensable aid to parents wanting to understand why their baby died and to determine the recurrence risk and management in subsequent pregnancy. Consequently, a perinatal death requires adequate diagnostic investigation. An important first step in the analysis of PD is to identify the case circumstances, including relevant details regarding maternal history, obstetric history and current pregnancy (complications are evaluated and recorded). In the next step, placental examination is suggested in all cases, together with molecular cytogenetic evaluation and fetal autopsy. Investigation for fetal-maternal hemorrhage by Kleihauer is also recommended as standard. In cases where parents do not consent to autopsy, alternative approaches such as minimally invasive postmortem examination, postmortem magnetic resonance imaging, and fetal photographs are good alternatives. After all investigations have been performed it is important to combine findings from the clinical review and investigations together, to identify the most probable cause of death and counsel the parents regarding their loss.

Early-Life Host-Microbiome Interphase: The Key Frontier for Immune Development

Human existence can be viewed as an "animal in a microbial world." A healthy interaction of the human host with the microbes in and around us heavily relies on a well-functioning immune system. As development of both the microbiota and the host immune system undergo rapid changes in early life, it is not surprising that even minor alterations during this co-development can have profound consequences. Scrutiny of existing data regarding pre-, peri-, as well as early postnatal modulators of newborn microbiota indeed suggest strong associations with several immune-mediated diseases with onset far beyond the newborn period. We here summarize these data and extract overarching themes. This same effort in turn sets the stage to guide effective countermeasures, such as probiotic administration. The objective of our review is to highlight the interaction of host immune ontogeny with the developing microbiome in early life as a critical window of susceptibility for lifelong disease, as well as to identify the enormous potential to protect and promote lifelong health by specifically targeting this window of opportunity.

Effectiveness of Continuum of Care-Linking Pre-Pregnancy Care and Pregnancy Care to Improve Neonatal and Perinatal Mortality: A Systematic Review and Meta-Analysis

REVIEW REGISTRATION

PROSPERO International prospective register of systematic reviews (CRD42015023424).

Stillbirths: The Hidden Birth Asphyxia - US and Global Perspectives

Stillbirths are among the most common pregnancy-related adverse outcomes but are more common in low-income and middle-income countries than in high-income countries. In high-income countries, most stillbirths occur early in the preterm period, whereas in low-income and middle-income countries, most occur in term or in late preterm births. In low-income and middle-income countries, conditions, such as prolonged or obstructed labor, placental abruption, preeclampsia/eclampsia, fetal growth restriction, fetal distress, breech and other abnormal presentations, and multiple births, are associated with stillbirth. In high-income countries, placental abnormalities are the most common associations. Globally, fetal asphyxia is likely the most common final pathway to stillbirth.

Post-mortem magnetic resonance foetal imaging: a study of morphological correlation with conventional autopsy and histopathological findings

The aim of the present study is to offer our experience concerning post-mortem magnetic resonance (PMMR) in foetal death cases and an evaluation of the differences between the findings acquired by PMMR and by forensic autopsy. Fifteen foetuses were recruited from July 2014 to December 2015. These had suffered intrauterine death in women in the 21st to 38th week of gestation who were treated in the emergency department for non-perception of foetal movements. We performed a PMMR on foetuses, 3 ± 1 days on average from the time of death, and then a complete forensic autopsy was performed. All 15 foetuses were examined with a whole-body study protocol, starting from the skull, down to and including the lower limbs. The total time of examination ranged from 20 to 30 min in each case. The external evaluation and description of post-mortem phenomena (maceration), record of the weight and detection and the various measurements of foetal diameters were evaluated before performing autopsy. A complete histopathological study was performed in each case. Out of 15 cases examined, eight were negative for structural anatomical abnormalities and/or diseases, both in the preliminary radiological examination and the traditional autopsy. In the remaining seven cases, pathological findings were detected by PMMR with corresponding results at autopsy. PMMR can provide useful information on foetal medical conditions and result in improved diagnostic classification. It may enable the planning of a more suitable technique before proceeding to autopsy, including focusing on certain aspects of organ pathology otherwise not detectable. The association between PMMR, post-mortem examination and related histological study of the foetus-placenta unit could help reduce the percentage of cases in which the cause of foetal death remains unexplained. Lastly, it may allow a selective sampling of the organ in order to target histological investigations.

Chorioamnionitis at Term: Definition, Diagnosis, and Implications for Practice

Chorioamnionitis is a serious complication during labor at term and is associated with adverse neonatal outcome affecting approximately 10% of pregnancies. It is diagnosed clinically or microbiologically or by histopathologic examination of the placenta and umbilical cord. The clinical criteria for chorioamnionitis found in preterm or term women include maternal fever combined with 2 or more findings of maternal tachycardia, fetal tachycardia, leukocytosis, uterine tenderness, and/or malodorous amniotic fluid. These subjective findings are neither sensitive nor specific. However, clinical chorioamnionitis requires a high index of suspicion, timely diagnosis, prompt antibiotic treatment, and delivery, which may help reduce the potentially devastating outcome of maternal and neonatal infections. This article focuses on clinical chorioamnionitis and presents the physiologic immune response during pregnancy, the definition of chorioamnionitis, clinical diagnostic criteria, and implications for practice.

Evaluation of the association of zoonotic Ljungan virus with perinatal deaths and fetal malformation

More and more epidemiologic and experimental data support the notion that Ljungan virus (LV), originally isolated from some rodent populations in Sweden, Denmark, and the United States, plays an important role in stillbirth and fetal malformation. Mouse dams infected with LV may result in uterine resorption and perinatal deaths that may cross generations, and their offspring may suffer high rates of malformations including cranial, brain, and limb malformations. In humans, researches founded that LV infection is related to malformation, intrauterine fetal death, and even central nervous system malformation. Although molecularly characterized, little is known about the biophysical nature of LV. Consequently, the role of LV infections in sudden infant death syndrome is still confusing, and the mechanism of how LV infections cause diseases is not clear. More research is clearly necessary to explore the mechanisms of LV infection in human and animal diseases to bring improvement to the clinical outcomes.

[Recurrent pregnancy losses: Etiological considerations and investigations, the point of view of the obstetrician-gynecologist]

Pregnancy loss is a general term including distinct well-defined entities: early miscarriage, late miscarriage, and stillbirth. It is important to clarify fetal loss circumstances to guide the diagnostic assessment of this issue. Etiological considerations in the presence of a fetal loss are very important to find the causes where a treatment exists and is efficient. The aim is also to explain to the couple, very affected by the event, the reason of the fetal loss and the potential risk of recurrence in a future pregnancy. In recent years, international guidelines changed and assessment of familial thrombophilia seems to be useless in this context. Feedback of the investigations will be better in a preconception consultation and multidisciplinary management of these couples is important for both therapeutic and psychological cares.

Regulatory T cells and the immune pathogenesis of prenatal infection

Pregnancy in placental mammals offers exceptional comprehensive benefits of in utero protection, nutrition, and metabolic waste elimination for the developing fetus. However, these benefits also require durable strategies to mitigate maternal rejection of fetal tissues expressing foreign paternal antigens. Since the initial postulate of expanded maternal immune tolerance by Sir Peter Medawar 60 years ago, an amazingly elaborate assortment of molecular and cellular modifications acting both locally at the maternal-placental interface and systemically have been shown to silence potentially detrimental maternal immune responses. In turn, simultaneously maintaining host defense against the infinite array of potential pathogens during pregnancy is equally important. Fortunately, resistance against most infections is preserved seamlessly throughout gestation. On the other hand, recent studies on pathogens with unique predisposition for prenatal infections have uncovered distinctive holes in host defense associated with the reproductive process. Using these infections to probe the response during pregnancy, the immune suppressive regulatory subset of maternal CD4 T cells has been increasingly shown to dictate the inter-workings between prenatal infection susceptibility and pathogenesis of ensuing pregnancy complications. Herein, the recent literature suggesting a necessity for maternal regulatory T cells (Tregs) in pregnancy-induced immunological shifts that sustain fetal tolerance is reviewed. Additional discussion is focused on how expansion of maternal Treg suppression may become exploited by pathogens that cause prenatal infections and the perilous potential of infection-induced immune activation that may mitigate fetal tolerance and inadvertently inject hostility into the protective in utero environment.

Influence of iron status on risk of maternal or neonatal infection and on neonatal mortality with an emphasis on developing countries

Infection is a major cause of neonatal death in developing countries. This review investigates whether host iron status affects the risk of maternal and/or neonatal infection, potentially contributing to neonatal death, and summarizes the iron acquisition mechanisms described for pathogens causing stillbirth, preterm birth, and congenital infection. In vitro evidence shows that iron availability influences the severity and chronicity of infections that cause these negative outcomes of pregnancy. In vivo evidence is lacking, as relevant studies of maternal iron supplementation have not assessed the effect of iron status on the risk of maternal and/or neonatal infection. Reducing iron-deficiency anemia among women is beneficial and should improve the iron stores of babies; moreover, there is evidence that iron status in young children predicts the risk of malaria and, possibly, the risk of invasive bacterial diseases. Caution with maternal iron supplementation is indicated in iron-replete women who may be at high risk of exposure to infection, although distinguishing between iron-replete and iron-deficient women is currently difficult in developing countries, where a point-of-care test is needed. Further research is indicated to investigate the risk of infection relative to iron status in mothers and babies in order to avoid iron intervention strategies that may result in detrimental birth outcomes in some groups of women.

Travel and pregnancy: an infectious diseases perspective

Increasing numbers of women are choosing to travel during pregnancy. In the presence of an altered immune state, exposure to certain microbes can be particularly harmful. We have undertaken a review of the literature in order to provide strategies to minimize the infectious disease risks of pregnant travel. Included is a discussion of common immunizing agents and their safety in pregnancy.