Assessment of Maternal and Neonatal SARS-CoV-2 Viral Load, Transplacental Antibody Transfer, and Placental Pathology in Pregnancies During the COVID-19 Pandemic

Vertical Transmission of SARS-CoV-2 during Pregnancy: A Prospective Italian Cohort Study

OBJECTIVE

 The extent of vertical transmission (VT) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from mothers their fetuses or neonates is still uncertain. We aimed to determine the incidence of VT.

STUDY DESIGN

 In this prospective cohort study. All mother diagnosed with SARS-CoV-2 infection at the time of delivery or up to 1 week prior and their neonates, managed in a tertiary referral hospital for pregnancy complicated by coronavirus disease 2019 (COVID-19) in Rome, from April 2 to December 22, 2020, were included. Maternal infection was defined as nasopharyngeal swab test results positive for SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR). Biological samples were collected before, at, and after delivery to test positivity for SARS-CoV-2 RT-PCR and anti-SARS-CoV-2-specific antibodies.

RESULTS

 The cohort included 95 women and 96 neonates with documented SARS-CoV-2 test results. Four neonates (4.2%) tested positive. The incidence of VT, according to the guidance criteria for diagnosing perinatal SARS-CoV-2 infection, was 5.2%. Neonatal symptoms were due to prematurity or fetal distress: symptomatic infants had lower median (min-max) gestational age, 38.1 (29.3-40.6) versus 39.3 (33.9-41.9) weeks (p = 0.036), and 1-minute and 5-minute Apgar scores, 9 (3-9) versus 9 (7-10) (p = 0.036) and 10 (6-10) versus 10 (8-10) (p = 0.012), respectively, than asymptomatic infants and needed more frequent assistance in the delivery room (22.2 vs 2.5%; p = 0.008). Only six (7.1%) neonates had anti-SARS-CoV-2-specific antibodies, despite the ongoing maternal infection.

CONCLUSION

 The incidence of VT is low as is the detection of specific anti-SARS-CoV-2 antibodies in cord blood when infection is contracted late in pregnancy. This would suggest poor protection of infants against horizontal transmission of the virus.

KEY POINTS

· VT of SARS-CoV-2 from pregnant mothers to fetuses or neonates can be possible.. · In this prospective cohort study, the incidence of VT is found to be 5.2%.. · VT is low but exists..

Association between maternal and perinatal outcomes and histological changes in the placenta of patients with Covid-19: A cohort study

Although studies evaluated placental involvement in Covid-19 patients, few have assessed its association with clinical repercussions. The study aimed to determine the association between the clinical status and maternal and perinatal outcomes of patients with Covid-19 at delivery and changes in placental histology. It is so far the largest cohort evaluating placentas of patients infected by the SARS-CoV-2. A secondary analysis was conducted of a database from which a cohort of 226 patients, who tested real-time polymerase chain reaction-positive for Covid-19 at delivery and whose placentas were collected and submitted to pathology, was selected for inclusion. One or more types of histological changes were detected in 44.7% of the 226 placentas evaluated. The most common abnormalities were maternal vascular malperfusion (38%), evidence of inflammation/infection (9.3%), fetal vascular malperfusion (0.8%), fibrinoid changes and intervillous thrombi (0.4%). Oxygen use (P = .01) and need for admission to an intensive care unit (ICU) (P = .04) were less common in patients with placental findings, and hospital stay was shorter in these patients (P = .04). There were more fetal deaths among patients with evidence of inflammation/infection (P = .02). Fetal death, albeit uncommon, is associated with findings of inflammation/infection. Oxygen use and need for admission to an ICU were less common among patients with placental findings, probably due to the pregnancy being interrupted early. None of the other findings was associated with maternal clinical status or with adverse perinatal outcome.

Neurodevelopmental delay in children exposed to maternal SARS-CoV-2 in-utero

It is unclear if SARS CoV-2 infection during pregnancy is associated with adverse neurodevelopmental repercussions to infants. We assessed pediatric neurodevelopmental outcomes in children born to mothers with laboratory-confirmed SARS CoV-2 infection during pregnancy. Neurodevelopmental outcomes of in-utero exposed children were compared to that of pre-pandemic control children in Los Angeles (LA), CA, USA and Rio de Janeiro, Brazil. Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III), the gold standard tool for evaluating neurodevelopment until 36 months of age and Ages and Stages Questionnaires (ASQ-3), a frequently used screening instrument for evaluating neurodevelopment in this same age group were the assessment tools used. Developmental delay (DD) was defined as having a score < - 2 SD below the norm (< 70) in at least one of three Bayley-III domains, (cognitive, motor or language) or a score below the cut-off (dark zone) in at least one of five ASQ-3 domains (communication, gross motor, fine motor, problem solving, personal-social). Exposed children were born between April 2020 and December 2022 while control children were born between January 2016 to December 2019. Neurodevelopmental testing was performed in 300 children total: 172 COVID-19 exposed children between 5-30 months of age and 128 control children between 6-38 months of age. Bayley-III results demonstrated that 12 of 128 exposed children (9.4%) had DD versus 2 of 128 controls (1.6%), p = 0.0007. Eight of 44 additional exposed children had DD on ASQ-3 testing. Fully, 20 of 172 exposed children (11.6%) and 2 of 128 control children (1.6%), p = 0.0006 had DD. In Rio, 12% of exposed children versus 2.6% of controls, p = 0.02 had DD. In LA, 5.7% of exposed children versus 0 controls, p = 0.12 had DD. Severe/critical maternal COVID-19 predicted below average neurodevelopment in the exposed cohort (OR 2.6, 95% CI 1.1-6.4). Children exposed to antenatal COVID-19 have a tenfold higher frequency of DD as compared to controls and should be offered neurodevelopmental follow-up.

Maternal COVID-19 exposure and placental characteristics

INTRODUCTION

The impact of COVID-19 on the placenta is poorly described, particularly among minority women.

MATERIALS AND METHODS

This is a retrospective case-control study. Micro- and macroscopic placental pathologic findings were compared for 15 COVID-19 positive and 36 negative mothers. Cases and controls were frequency matched on gestational age, race, maternal comorbidities, and delivery type. Data from the electronic medical record were supplemented with independent review of microscopic slides.

RESULTS

Placentas from cases and controls were similar except the median distance from the site of the cord insertion to the nearest disk margin was statistically significantly shorter among placentas from COVID-19 positive cases (3.5 versus 6.0 cm, p = 0.006). Case status was not associated with an increased risk of placental pathologies.

CONCLUSION

There are few pathologic differences between placentas of COVID-19 positive and negative mothers. Additional studies are needed to investigate the role of timing of infection.

Seroprevalence and placental transfer of SARS-CoV-2 antibodies in unvaccinated pregnant women

PURPOSE

Pregnant women are at risk of severe SARS-CoV-2 infection, potentially leading to obstetric and neonatal complications. Placental transfer of antibodies directed to SARS-CoV-2 may be protective against neonatal COVID-19, but this remains to be studied. We aimed to determine the seroprevalence of SARS-CoV-2 antibodies in a population of unvaccinated pregnant women and to determine the placental transfer of these antibodies.

METHODOLOGY

A total of 1197 unvaccinated women with mostly unknown pre-study SARS-CoV-2 infection status, were tested at delivery for SARS-CoV-2 spike protein IgG antibodies during the first year of the pandemic. Umbilical cord samples were collected and assessed for seropositivity if the mother was seropositive. Maternal characteristics, pregnancy and neonatal outcomes and data on SARS-CoV-2 infection were extracted from medical records.

RESULTS

Specific IgG were detected in 258 women (21.6%). A significant placental transfer to the newborn was observed in 81.3% of cases. The earlier in the 2nd and 3rd trimesters that the mother had contracted the disease and the more symptomatic she was, the greater the likelihood of transplacental transfer of IgG to her newborn.

CONCLUSION

Approximately one in five women had detectable anti-SARS-CoV-2 spike protein IgG antibodies at delivery during the first year of the pandemic, and these antibodies were significantly transferred to their fetuses. This research provides further evidence to better understand the dynamics of the placental transfer of SARS-CoV-2 IgG antibodies from mothers to their newborns, which is necessary to improve vaccination strategies.

Effect of Early pregnancy associated protein-1 on Spike protein and ACE2 interactions: Implications in SARS Cov-2 vertical transmission

INTRODUCTION

Several factors influence transmission of 2019-nCoV from mother to fetus during pregnancy, thus the dynamics of vertical transmission is unclear. The role of cellular protective factors, namely a 90 KDa glycoprotein, Early pregnancy-associated protein (Epap-1), expressed by placental endothelial cells in women during early pregnancy would provide an insight into role of placental factors in virus transmission. Since viral spike protein binding to the ACE2 receptors of the host cells promotes virus invasion in placental tissue, an analysis of effects of Epap-1 on the Spike-ACE2 protein binding was studied.

METHODS

Epap-1 was isolated from MTP placental tissue. Molecular interaction of Epap-1 and variants of the spike was analyzed in silco. The interaction of Epap-1 with Spike and RBD were analyzed using ELISA and immunofluorescence studies.

RESULTS

The results in silico showed an interaction of Epap-1 with S-protein at RBD region involving K417, Y449, Y453, Y456, Y473, Q474, F486, Q498, N501 residues of spike with Y61, F287, I302, N303, N305, S334, N465, G467, N468 residues of Epap-1 leading to interference of S-protein and ACE2 interaction [1]. Further, the interaction is conserved among the variants. The studies in vitro confirm that Epap-1 affects S protein-ACE2 and RBD- ACE2 binding, thus suggesting that during early pregnancy, SARS CoV-2 infection may be protected by Epap-1 protein present in placental tissue. The results were further confirmed by pseudovirus expressing Spike and RBD in an infection assay.

DISCUSSION

Epap-1 interferes with Spike and RBD interaction with ACE2, suggesting a possible mechanism of the antiviral environment during pregnancy.

Effects of the timing of maternal SARS-CoV-2 infection and vaccination status on placental transfer of antibodies to neonates: a cross-sectional study

OBJECTIVE

To assess the effects of timing of maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and vaccination status on placental transfer of antibodies to neonates.

METHODS

In this cross-sectional study, chemiluminescence was employed to measure SARS-CoV-2 IgG antibody titers in paired maternal-infant samples from women infected during pregnancy who were vaccinated or unvaccinated. Generalized linear regression assessed factors affecting antibody transfer in infected pregnant women and neonatal titers.

RESULTS

The group with ≥90 days between infection and delivery showed a higher antibody transfer rate than the <90 days group(β= 0.33, 95%CI: 0.01-0.65). Neonatal IgG titers correlated significantly with maternal titers and with maternal infections more than 90 days before delivery. Among infected pregnant women, those who had received two or three doses of vaccine before pregnancy had higher neonatal antibody titers than those who were not vaccinated (β = 57.70, 95%CI: 31.33-84.07).

CONCLUSION

Neonates born to pregnant women who were vaccinated before infection showed higher antibody titers than neonates of pregnant women who were not vaccinated before infection. The transfer rate is higher in pregnant women with ≥90 days from infection to delivery than in those with <90 days. These findings highlight the importance of timely maternal vaccination to optimize maternal and infant immunity.

Efficient transplacental transfer of SARS-CoV-2 antibodies between naturally exposed mothers and infants in Accra, Ghana

We aimed to determine SARS-CoV-2 antibody seropositivity among pregnant women and the transplacental transfer efficiency of SARS-CoV-2-specific antibodies relative to malaria antibodies among SARS-CoV-2 seropositive mother-cord pairs. This cross-sectional study was conducted in Accra, Ghana, from March to May 2022. Antigen- specific IgG antibodies against SARS-CoV-2 (nucleoprotein and spike-receptor binding domain) and malarial antigens (circumsporozoite protein and merozoite surface protein 3) in maternal and cord plasma were measured by ELISA. Plasma from both vaccinated and unvaccinated pregnant women were tested for neutralizing antibodies using commercial kit. Of the unvaccinated pregnant women tested, 58.12% at antenatal clinics and 55.56% at the delivery wards were seropositive for both SARS-CoV-2 nucleoprotein and RBD antibodies. Anti-SARS-CoV-2 antibodies in cord samples correlated with maternal antibody levels (N antigen rs = 0.7155, p < 0.001; RBD rs = 0.8693, p < 0.001). Transplacental transfer of SARS-CoV-2 nucleoprotein antibodies was comparable to circumsporozoite protein antibodies (p = 0.9999) but both were higher than transfer rates of merozoite surface protein 3 antibodies (p < 0.001). SARS-CoV-2 IgG seropositivity among pregnant women in Accra is high with a boost of SARS-CoV-2 RBD-specific IgG in vaccinated women. Transplacental transfer of anti-SARS-CoV-2 and malarial antibodies was efficient, supporting vaccination of mothers as a strategy to protect infants against SARS-CoV-2.

Neonatal immune cells have heightened responses following in-utero exposure to chorioamnionitis or COVID-19

BACKGROUND

Chorioamnionitis alters neonatal immune responses. Gestational COVID-19 infection is associated with adverse pregnancy outcomes, but its impact on neonatal immunity is unclear. We hypothesized that gestational COVID-19 exposure would result in exaggerated neonatal immune responses, similar to chorioamnionitis-exposed neonates.

METHODS

Term umbilical cord blood mononuclear cells (CBMCs) were isolated from neonates exposed to chorioamnionitis, gestational COVID-19 or unexposed controls. CBMCs were cultured and stimulated with heat-killed Escherichia coli, Streptococcus agalactiae or Staphylococcus epidermidis. A multiplexed protein assay was used to measure cytokine levels in cell culture supernatants and flow cytometry was used to evaluate cellular-level cytokine expression.

RESULTS

Both chorioamnionitis-exposed and COVID-19 exposed CBMCs demonstrated upregulation of IL-1β and IL-6 compared to unexposed CBMCs, while only COVID-19 exposure resulted in IL-8 upregulation. There were no differences between chorioamnionitis-exposed and COVID-19 exposed CBMCs when these groups were directly compared. Flow cytometry demonstrated immune cell subset specific differences in cytokine expression between the exposure groups.

CONCLUSION

The fetal/neonatal response to maternal inflammation differed based on immune cell subset and etiology of inflammation, but the global neonatal cytokine responses were similar between exposure groups. This suggests that targeting perinatal inflammation rather than the specific etiology may be a possible therapeutic approach.

IMPACT

Neonatal immune cells have similar pathogen-associated global cytokine responses, but different cell-level immune responses, following in-utero exposure to chorioamnionitis or COVID-19. This is the first study to directly compare immune responses between neonates exposed to chorioamnionitis and COVID-19. This suggests that the fetal/neonatal cellular response to perinatal inflammation differs based on the etiology and severity of maternal inflammation, but still results in a similar overall inflammatory profile regardless of the cause of perinatal inflammation.

Association between the COVID-19 pandemic and childhood development aged 30 to 36 months in South Korea, based on the National health screening program for infants and children database

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has had a significant impact on the neurodevelopment of children. However, the precise effects of the virus and the social consequences of the pandemic on pediatric neurodevelopment are not yet fully understood. We aimed to compare the neurodevelopment of children between before and during the COVID-19 pandemic, as well as examine the impact of socioeconomic status (SES) and regional differences on the development.

METHODS

The study used the Korean Developmental Screening Test to compare the difference in the risk of neurodevelopmental delay between before and during the COVID-19 pandemic. Multivariable logistic regression analysis was conducted to identify the relationship between experiencing the COVID-19 pandemic and the risk of neurodevelopmental delay. Stratified analyses were performed to determine whether the developmental delays caused by the pandemic's impact varied depending on SES or regional inequality.

RESULTS

This study found an association between the experience of COVID-19 and a higher risk of neurodevelopmental delay in communication (adjusted OR [aOR]: 1.21, 95% confidence interval [CI]: 1.19, 1.22; P-value: < 0.0001) and social interaction (aOR: 1.15, 95% CI: 1.13, 1.17; P-value: < 0.0001) domains among children of 30-36 months' ages. Notably, the observed association in the Medicaid group of children indicates a higher risk of neurodevelopmental delay compared to those in the non-Medicaid group.

CONCLUSIONS

These findings highlight the need to be concerned about the neurodevelopment of children who experienced the COVID-19 pandemic. The study also calls for increased training and support for Medicaid children, parents, teachers, and healthcare practitioners. Additionally, policy programs focused on groups vulnerable to developmental delays are required.

Chronic villitis as a distinctive feature of placental injury in maternal SARS-CoV-2 infection

BACKGROUND

SARS-CoV-2 infection during pregnancy is associated with an increased risk for stillbirth, preeclampsia, and preterm birth. However, this does not seem to be caused by intrauterine fetal infection because vertical transmission is rarely reported. There is a paucity of data regarding the associated placental SARS-CoV-2 histopathology and their relationship with the timing and severity of infection.

OBJECTIVE

This study aimed to determine if maternal SARS-CoV-2 infection was associated with specific patterns of placental injury and if these findings differed by gestational age at time of infection or disease severity.

STUDY DESIGN

A retrospective cohort study was performed at the University of California San Diego between March 2020 and February 2021. Placentas from pregnancies with a positive SARS-CoV-2 test were matched with 2 sets of controls; 1 set was time-matched by delivery date and sent to pathology for routine clinical indications, and the other was chosen from a cohort of placentas previously collected for research purposes without clinical indications for pathologic examination before the SARS-CoV-2 outbreak. Placental pathologic lesions were defined based on standard criteria and included maternal and fetal vascular malperfusion and acute and chronic inflammatory lesions. A bivariate analysis was performed using the independent Student t test and Pearson chi-square test. A logistic regression was used to control for relevant covariates. Regions of SARS-CoV-2-associated villitis were further investigated using protein-based digital spatial profiling assays on the GeoMx platform, validated by immunohistochemistry, and compared with cases of infectious villitis and villitis of unknown etiology. Differential expression analysis was performed to identify protein expression differences between these groups of villitis.

RESULTS

We included 272 SARS-CoV-2 positive cases, 272 time-matched controls, and 272 historic controls. The mean age of SARS-CoV-2 affected subjects was 30.1±5.5 years and the majority were Hispanic (53.7%) and parous (65.7%). SARS-CoV-2 placentas demonstrated a higher frequency of the 4 major patterns of placental injury (all P<.001) than the historic controls. SARS-CoV-2 placentas also showed a higher frequency of chronic villitis and severe chronic villitis (P=.03 for both) than the time-matched controls, which remained significant after controlling for gestational age at delivery (adjusted odds ratio, 1.52; 95% confidence interval, 1.01-2.28; adjusted odds ratio, 2.12; 95% confidence interval, 1.16-3.88, respectively). Digital spatial profiling revealed that programmed death-ligand 1 was increased in villitis-positive regions of the SARS-CoV-2 (logFC, 0.47; adjusted P value =.002) and villitis of unknown etiology (logFC, 0.58; adjusted P value =.003) cases, but it was conversely decreased in villitis-positive regions of the infectious villitis group (log FC, -1.40; adjusted P value <.001).

CONCLUSION

Chronic villitis seems to be the most specific histopathologic finding associated with SARS-CoV-2 maternal infection. Chronic villitis involves damage to the vasculosyncytial membrane of the chorionic villi, which are involved in gas and nutrient exchange, suggesting potential mechanisms of placental (and perhaps neonatal) injury, even in the absence of vertical transmission. Surprisingly, changes in protein expression in SARS-CoV-2-associated villitis seem to be more similar to villitis of unknown etiology than to infectious villitis.

Neonatal SARS-CoV-2 immunoglobulin G antibodies at delivery and their impact on COVID-19

OBJECTIVE

To assess neonatal SARS-CoV-2 anti-spike IgG antibody levels after maternal mRNA COVID-19 vaccination and/or infection during pregnancy and evaluate their protective effect.

METHODS

Prospective observational study, conducted from January 2021 to December 2022. Infants were tested for anti-spike IgG antibodies at birth and then every 3 months until disappearance of titer. A follow-up was done for SARS-CoV-2 infection up to 12 months.

RESULTS

In total, 147 newborns were enrolled with a median (IQR) gestational age of 39.60 weeks (38.3-40.4). Median (IQR) titers in UA/ml at 2 days were higher (P < .001) in newborns of vaccinated 7063.7 (2841.4-14,448.1), than of infected mothers 372.7 (158.00-884.90). Titers dropped significantly during the follow-up but 50% still had a detectable titer at 6 months. A high antibody titer at 2 days led to a longer persistence (HR 0.89, IC 95% 0.83-0.96, P = .004). In total, 36 infants were infected during the first months of life coinciding with the Omicron variant. Fifty percent had detectable antibodies during the infection period. Relationship between high IgG titers and month of infection was inverse (RHO - 0.52, P = .009).

CONCLUSION

Though a high antibody titer at birth led to longer persistence, no protective effect against infection was found. As newborns are a high risk group for COVID-19, avoiding transmission during the first year of life is important.

Reduced control of SARS-CoV-2 infection associates with lower mucosal antibody responses in pregnancy

Pregnant patients are at greater risk of hospitalization with severe COVID-19 than non-pregnant people. This was a retrospective observational cohort study of remnant clinical specimens from patients who visited acute care hospitals within the Johns Hopkins Health System in the Baltimore, MD-Washington DC, area between October 2020 and May 2022. Participants included confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected pregnant people and matched non-pregnant people (the matching criteria included age, race/ethnicity, area deprivation index, insurance status, and vaccination status to ensure matched demographics). The primary dependent measures were clinical COVID-19 outcomes, infectious virus recovery, viral RNA levels, and mucosal anti-spike (S) IgG titers from upper respiratory tract samples. A total of 452 individuals (117 pregnant and 335 non-pregnant) were included in the study, with both vaccinated and unvaccinated individuals represented. Pregnant patients were at increased risk of hospitalization (odds ratio [OR] = 4.2; confidence interval [CI] = 2.0-8.6), intensive care unit admittance (OR = 4.5; CI = 1.2-14.2), and being placed on supplemental oxygen therapy (OR = 3.1; CI = 1.3-6.9). Individuals infected during their third trimester had higher mucosal anti-S IgG titers and lower viral RNA levels (P < 0.05) than those infected during their first or second trimesters. Pregnant individuals experiencing breakthrough infections due to the Omicron variant had reduced anti-S IgG compared to non-pregnant patients (P < 0.05). The observed increased severity of COVID-19 and reduced mucosal antibody responses particularly among pregnant participants infected with the Omicron variant suggest that maintaining high levels of SARS-CoV-2 immunity through booster vaccines may be important for the protection of this at-risk population.IMPORTANCEIn this retrospective observational cohort study, we analyzed remnant clinical samples from non-pregnant and pregnant individuals with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections who visited the Johns Hopkins Hospital System between October 2020 and May 2022. Disease severity, including intensive care unit admission, was greater among pregnant than non-pregnant patients. Vaccination reduced recovery of infectious virus and viral RNA levels in non-pregnant patients, but not in pregnant patients. In pregnant patients, increased nasopharyngeal viral RNA levels and recovery of infectious virus were associated with reduced mucosal IgG antibody responses, especially among women in their first trimester of pregnancy or experiencing breakthrough infections from Omicron variants. Taken together, this study provides insights into how pregnant patients are at greater risk of severe COVID-19. The novelty of this study is that it focuses on the relationship between the mucosal antibody response and its association with virus load and disease outcomes in pregnant people, whereas previous studies have focused on serological immunity. Vaccination status, gestational age, and SARS-CoV-2 omicron variant impact mucosal antibody responses and recovery of infectious virus from pregnant patients.

Mendelian randomization analysis reveals causal relationship between obstetric-related diseases and COVID-19

BACKGROUND

Several observational studies demonstrated that pregnant individuals with COVID-19 had a higher risk of preeclampsia and preterm birth. We aimed to determine whether women with COVID-19 diagnosis had adverse pregnancy outcomes.

METHODS

A two-sample Mendelian randomization (MR) analysis in this study was used to evaluate the casual relationships between COVID-19 infection and obstetric-related diseases based on genome-wide association studies (GWAS) dataset. Inverse-variance weighted (IVW), MR-Egger and MR-PRESSO were used to infer the connection and estimate the pleiotropy respectively.

RESULTS

The significant connection was observed between COVID-19 and placental disorders with betaIVW of 1.57 and odds ratio (OR) of 4.81 (95% confidence interval [CI]: 1.05-22.05, p = 0.04). However, there were no associations between COVID-19 infection and gestational diabetes mellitus (GDM) (OR = 1.12; 95% CI: 0.85-1.45, p = 0.41), other disorders of amniotic fluid and membranes (OR = 0.90; 95% CI: 0.61-1.32, p = 0.59), Intrahepatic Cholestasis of Pregnancy (ICP) (OR = 1.42; 95% CI: 0.85-2.36, p = 0.18), birth weight (OR = 1.02; 95% CI: 0.99-1.05, p = 0.19), gestational hypertension (OR = 1.00; 95% CI: 1.00-1.00, p = 0.85), spontaneous miscarriages (OR = 1.00; 95% CI: 0.96-1.04, p = 0.90) and stillbirth (OR = 1.00; 95% CI: 0.98-1.01, p = 0.62).

CONCLUSION

There was no direct causal relationship between COVID-19 infection and maternal and neonatal poor outcomes. Our study could alleviate the anxiety of pregnant women under the COVID-19 pandemic conditions partly.

COVID-19 vaccination protects infected pregnant women from developing SARS-CoV-2 placentitis and decreases the risk for stillbirth

INTRODUCTION

The impact of COVID-19 infection in pregnant women remained unclear for a long time. Previous research showed that SARS-CoV-2 virus is able to infect the placenta, potentially causing significant lesions leading to placental insufficiency. The impact of maternal vaccination status on the prevalence of SARS-CoV-2 placentitis remains unclear. We characterized placental lesions in SARS-CoV-2 infected pregnant women and studied the impact of vaccination on placental involvement.

METHODS

We retrospectively studied 180 placentas sent to the Department of Pathology in UZ Leuven or AZ Turnhout between January 2020 and August 2022, from non-vaccinated and vaccinated mothers suffering a SARS-CoV-2 proven infection during pregnancy. All reports and hematoxylin-eosin stained sections were revised by two pathologists to determine the presence of histopathological lesions that have been described in SARS-CoV-2 infection. SARS-CoV-2 immunostainings were available for a subgroup of 109 placentas. We gathered clinical data: date of delivery, date of positive serologic test result, vaccination status, SARS-CoV-2 variant and outcome of the pregnancy.

RESULTS

Of the 180 placentas, 37,2% showed histopathological lesions and in 12,8% an immunohistochemically proven SARS-CoV-2 placentitis was present. SARS-CoV-2 immunohistochemical positivity was only seen in non-vaccinated mothers. The risk of fetal demise was more than 5 times higher for non-vaccinated mothers and their placentas showed significantly more syncytiotrophoblast necrosis and chronic histiocytic intervillositis compared to vaccinated mothers (both p < 0,001).

DISCUSSION

Maternal vaccination was associated with a reduced risk of SARS-CoV-2 placentitis and stillbirth. This study provides new evidence of the protective effect of vaccination on the placenta.

COVID-19 in pregnant women: a systematic review and meta-analysis on the risk and prevalence of pregnancy loss

BACKGROUND

Pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are more likely to experience preterm birth and their neonates are more likely to be stillborn or admitted to a neonatal unit. The World Health Organization declared in May 2023 an end to the coronavirus disease 2019 (COVID-19) pandemic as a global health emergency. However, pregnant women are still becoming infected with SARS-CoV-2 and there is limited information available regarding the effect of SARS-CoV-2 infection in early pregnancy on pregnancy outcomes.

OBJECTIVE AND RATIONALE

We conducted this systematic review to determine the prevalence of early pregnancy loss in women with SARS-Cov-2 infection and compare the risk to pregnant women without SARS-CoV-2 infection.

SEARCH METHODS

Our systematic review is based on a prospectively registered protocol. The search of PregCov19 consortium was supplemented with an extra electronic search specifically on pregnancy loss in pregnant women infected with SARS-CoV-2 up to 10 March 2023 in PubMed, Google Scholar, and LitCovid. We included retrospective and prospective studies of pregnant women with SARS-CoV-2 infection, provided that they contained information on pregnancy losses in the first and/or second trimester. Primary outcome was miscarriage defined as a pregnancy loss before 20 weeks of gestation, however, studies that reported loss up to 22 or 24 weeks were also included. Additionally, we report on studies that defined the pregnancy loss to occur at the first and/or second trimester of pregnancy without specifying gestational age, and for second trimester miscarriage only when the study presented stillbirths and/or foetal losses separately from miscarriages. Data were stratified into first and second trimester. Secondary outcomes were ectopic pregnancy (any extra-uterine pregnancy), and termination of pregnancy. At least three researchers independently extracted the data and assessed study quality. We calculated odds ratios (OR) and risk differences (RDs) with corresponding 95% CI and pooled the data using random effects meta-analysis. To estimate risk prevalence, we performed meta-analysis on proportions. Heterogeneity was assessed by I2.

OUTCOMES

We included 120 studies comprising a total of 168 444 pregnant women with SARS-CoV-2 infection; of which 18 233 women were in their first or second trimester of pregnancy. Evidence level was considered to be of low to moderate certainty, mostly owing to selection bias. We did not find evidence of an association between SARS-CoV-2 infection and miscarriage (OR 1.10, 95% CI 0.81-1.48; I2 = 0.0%; RD 0.0012, 95% CI -0.0103 to 0.0127; I2 = 0%; 9 studies, 4439 women). Miscarriage occurred in 9.9% (95% CI 6.2-14.0%; I2 = 68%; 46 studies, 1797 women) of the women with SARS CoV-2 infection in their first trimester and in 1.2% (95% CI 0.3-2.4%; I2 = 34%; 33 studies; 3159 women) in the second trimester. The proportion of ectopic pregnancies in women with SARS-CoV-2 infection was 1.4% (95% CI 0.02-4.2%; I2 = 66%; 14 studies, 950 women). Termination of pregnancy occurred in 0.6% of the women (95% CI 0.01-1.6%; I2 = 79%; 39 studies; 1166 women).

WIDER IMPLICATIONS

Our study found no indication that SARS-CoV-2 infection in the first or second trimester increases the risk of miscarriages. To provide better risk estimates, well-designed studies are needed that include pregnant women with and without SARS-CoV-2 infection at conception and early pregnancy and consider the association of clinical manifestation and severity of SARS-CoV-2 infection with pregnancy loss, as well as potential confounding factors such as previous pregnancy loss. For clinical practice, pregnant women should still be advised to take precautions to avoid risk of SARS-CoV-2 exposure and receive SARS-CoV-2 vaccination.

Seroepidemiology of SARS-CoV-2 in a cohort of pregnant women and their infants in Uganda and Malawi

BACKGROUND

Data on SARS-CoV-2 infection in pregnancy and infancy has accumulated throughout the course of the pandemic, though evidence regarding asymptomatic SARS-CoV-2 infection and adverse birth outcomes are scarce. Limited information is available from countries in sub-Saharan Africa (SSA). The pregnant woman and infant COVID in Africa study (PeriCOVID Africa) is a South-South-North partnership involving hospitals and health centres in five countries: Malawi, Uganda, Mozambique, The Gambia, and Kenya. The study leveraged data from three ongoing prospective cohort studies: Preparing for Group B Streptococcal Vaccines (GBS PREPARE), SARS-CoV-2 infection and COVID-19 in women and their infants in Kampala and Mukono (COMAC) and Pregnancy Care Integrating Translational Science Everywhere (PRECISE). In this paper we describe the seroepidemiology of SARS-CoV-2 infection in pregnant women enrolled in sites in Uganda and Malawi, and the impact of SARS-CoV-2 infection on pregnancy and infant outcomes.

OUTCOME

Seroprevalence of SARS-CoV-2 antibodies in maternal blood, reported as the proportion of seropositive women by study site and wave of COVID-19 within each country.

METHODS

The PeriCOVID study was a prospective mother-infant cohort study that recruited pregnant women at any gestation antenatally or on the day of delivery. Maternal and cord blood samples were tested for SARS-CoV-2 antibodies using Wantai and Euroimmune ELISA. In periCOVID Uganda and Malawi nose and throat swabs for SARS-Cov-2 RT-PCR were obtained.

RESULTS

In total, 1379 women were enrolled, giving birth to 1387 infants. Overall, 63% of pregnant women had a SARS-CoV-2 positive serology. Over subsequent waves (delta and omicron), in the absence of vaccination, seropositivity rose from 20% to over 80%. The placental transfer GMR was 1.7, indicating active placental transfer of anti-spike IgG. There was no association between SARS-CoV-2 antibody positivity and adverse pregnancy or infancy outcomes.

Management of COVID-19-Associated Acute Respiratory Distress Syndrome (ARDS) During Pregnancy Following In Vitro Fertilization (IVF)

Coronavirus disease 2019 (COVID-19), the disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is recognized for its heterogeneous clinical presentation, complex pathophysiology, and broad spectrum of manifestations. Obstetric patients have been a subject of considerable interest due to their potential vulnerability to more severe infection and adverse pregnancy outcomes, exemplified by this report of a 43-year-old pregnant female with severe COVID-19 infection and respiratory complications. This case report aims to contribute to the existing scientific knowledge by presenting a detailed clinical profile of a patient with COVID-19 who achieved pregnancy through in vitro fertilization (IVF) and discussing the management and outcomes of the infection. The neonate's negative COVID-19 tests suggest no intrauterine transmission; prompt medical interventions, including mechanical ventilation and targeted antibiotic therapy, were implemented to stabilize her condition. Close collaboration among the multidisciplinary team and careful monitoring of vital functions and laboratory parameters were crucial in managing the patient's complex condition. Thus, this case highlights the importance of a comprehensive and multidisciplinary approach in managing severe COVID-19 cases in pregnancy, emphasizing the need for prompt recognition of complications and timely intervention.

SARS-CoV-2-Placental effects and association with stillbirth

SARS-CoV-2 has had a significant impact on pregnancy outcomes due to the effects of the virus and the altered healthcare environment. Stillbirth has been relatively hidden during the COVID-19 pandemic, but a clear link between SARS-CoV-2 and poor fetal outcome emerged in the Alpha and Delta waves. A small minority of women/birthing people who contracted COVID-19 developed SARS-CoV-2 placentitis. In many reported cases this was linked to intrauterine fetal death, although there are cases of delivery just before imminent fetal demise and we shall discuss how some cases are sub-clinical. What is surprising, is that SARS-CoV-2 placentitis is often not associated with severe maternal COVID-19 infection and this makes it difficult to predict. The worst outcomes seem to be with diffuse placental disease which occurs within 21 days of COVID-19 diagnosis. Poor outcomes are often pre-dated by reduced fetal movements but are not associated with ultrasound changes. In some cases, there has also been maternal thrombocytopenia, or coagulation abnormalities, which may provide a clue as to which pregnancies are at risk of fetal demise if a further variant of concern is to emerge. In future, multidisciplinary collaboration and cross-boundary working must be prioritised, to identify quickly such a phenomenon and provide clinicians with clear guidance for reducing fetal death and associated poor outcomes. While we wait to see if COVID-19 brings a future variant of concern, we must focus on appropriate future management of women who have had SARS-CoV-2 placentitis. As a placental condition with an infectious aetiology, SARS-CoV-placentitis is unlikely to recur in a subsequent pregnancy and thus a measured approach to subsequent pregnancy management is needed.

COVID-19 during pregnancy alters circulating extracellular vesicle cargo and their effects on trophoblast

SARS-CoV-2 infection and the resulting coronavirus disease (COVID-19) complicate pregnancies as the result of placental dysfunction which increases the risk of adverse pregnancy outcomes. While abnormal placental pathology resulting from COVID-19 is common, direct infection of the placenta is rare. This suggests maternal response to infection is responsible for placental dysfunction. We hypothesized that maternal circulating extracellular vesicles (EVs) are altered by COVID-19 during pregnancy and contribute to placental dysfunction. To examine this, we characterized maternal circulating EVs from pregnancies complicated by COVID-19 and tested their functional effect on trophoblast cells in vitro. We found the timing of infection is a major determinant of the effect of COVID-19 on circulating EVs. Additionally, we found differentially expressed EV mRNA cargo in COVID-19 groups compared to Controls that regulates the differential gene expression induced by COVID-19 in the placenta. In vitro exposure of trophoblasts to EVs isolated from patients with an active infection, but not EVs isolated from Controls, reduced key trophoblast functions including hormone production and invasion. This demonstrates circulating EVs from subjects with an active infection disrupt vital trophoblast function. This study determined that COVID-19 has a long-lasting effect on circulating EVs and circulating EVs are likely to participate in the placental dysfunction induced by COVID-19.

Analysis of the transplacental transmission of SARS CoV-2 virus and antibody transfer according to the gestational age at maternal infection

To quantify transplacental transmission of SARS-CoV-2 virus and antibody transfer in pregnant women and their newborns according to the gestational age at maternal infection. A prospective observational multicenter study including pregnant women with a positive RT-PCR or a positive serology for SARS-CoV-2 and compatible symptoms, from April to December 2020, in 11 French maternities. The study was designed to obtain a systematic collection of mother-infant dyad's samples at birth. SARS-CoV-2 viral load was measured by RT-PCR. IgG and IgM antibodies against the SARS-CoV-2 spike protein were measured by enzyme-linked immunosorbent assay. Antibody concentrations and transplacental transfer ratios were analyzed according to the gestational age at maternal infection. The primary outcome was the rate of SARS CoV-2 materno-fetal transmission at birth. The secondary outcome was the quantification of materno-fetal antibody transfer. Maternal and neonatal outcomes at birth were additionally assessed. Among 165 dyads enrolled, one congenital infection was confirmed {n = 1 (0.63%) IC95% [0.02%; 3.48%]}. The average placental IgG antibody transfer ratio was 1.27 (IC 95% [0.69-2.89]). The transfer ratio increased with increasing time between the onset of maternal infection and delivery (P Value = 0.0001). Maternal and neonatal outcomes were reassuring. We confirmed the very low rate of SARS-CoV-2 transplacental transmission (< 1%). Maternal antibody transfer to the fetus was more efficient when the infection occurred during the first and second trimester of pregnancy.

SARS-CoV-2 infection elucidates unique features of pregnancy-specific immunity

Pregnancy is a risk factor for increased severity of SARS-CoV-2 and other respiratory infections. The mechanisms underlying this risk have not been well-established, partly due to a limited understanding of how pregnancy shapes immune responses. To gain insight into the role of pregnancy in modulating immune responses at steady state and upon perturbation, we collected peripheral blood mononuclear cells (PBMC), plasma, and stool from 226 women, including 152 pregnant individuals (n = 96 with SARS-CoV-2 infection and n = 56 healthy controls) and 74 non-pregnant women (n = 55 with SARS-CoV-2 and n = 19 healthy controls). We found that SARS-CoV-2 infection was associated with altered T cell responses in pregnant compared to non-pregnant women. Differences included a lower percentage of memory T cells, a distinct clonal expansion of CD4-expressing CD8 + T cells, and the enhanced expression of T cell exhaustion markers, such as programmed cell death-1 (PD-1) and T cell immunoglobulin and mucin domain-3 (Tim-3), in pregnant women. We identified additional evidence of immune dysfunction in severely and critically ill pregnant women, including a lack of expected elevation in regulatory T cell (Treg) levels, diminished interferon responses, and profound suppression of monocyte function. Consistent with earlier data, we found maternal obesity was also associated with altered immune responses to SARS-CoV-2 infection, including enhanced production of inflammatory cytokines by T cells. Certain gut bacterial species were altered in pregnancy and upon SARS-CoV-2 infection in pregnant individuals compared to non-pregnant women. Shifts in cytokine and chemokine levels were also identified in the sera of pregnant individuals, most notably a robust increase of interleukin-27 (IL-27), a cytokine known to drive T cell exhaustion, in the pregnant uninfected control group compared to all non-pregnant groups. IL-27 levels were also significantly higher in uninfected pregnant controls compared to pregnant SARS-CoV-2-infected individuals. Using two different preclinical mouse models of inflammation-induced fetal demise and respiratory influenza viral infection, we found that enhanced IL-27 protects developing fetuses from maternal inflammation but renders adult female mice vulnerable to viral infection. These combined findings from human and murine studies reveal nuanced pregnancy-associated immune responses, suggesting mechanisms underlying the increased susceptibility of pregnant individuals to viral respiratory infections.

Whole transcriptome profiling of placental pathobiology in SARS-CoV-2 pregnancies identifies placental dysfunction signatures

Objectives

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) virus infection in pregnancy is associated with higher incidence of placental dysfunction, referred to by a few studies as a 'preeclampsia-like syndrome'. However, the mechanisms underpinning SARS-CoV-2-induced placental malfunction are still unclear. Here, we investigated whether the transcriptional architecture of the placenta is altered in response to SARS-CoV-2 infection.

Methods

We utilised whole-transcriptome, digital spatial profiling, to examine gene expression patterns in placental tissues from participants who contracted SARS-CoV-2 in the third trimester of their pregnancy (n = 7) and those collected prior to the start of the coronavirus disease 2019 (COVID-19) pandemic (n = 9).

Results

Through comprehensive spatial transcriptomic analyses of the trophoblast and villous core stromal cell subpopulations in the placenta, we identified SARS-CoV-2 to promote signatures associated with hypoxia and placental dysfunction. Notably, genes associated with vasodilation (NOS3), oxidative stress (GDF15, CRH) and preeclampsia (FLT1, EGFR, KISS1, PAPPA2) were enriched with SARS-CoV-2. Pathways related to increased nutrient uptake, vascular tension, hypertension and inflammation were also enriched in SARS-CoV-2 samples compared to uninfected controls.

Conclusions

Our findings demonstrate the utility of spatially resolved transcriptomic analysis in defining the underlying pathogenic mechanisms of SARS-CoV-2 in pregnancy, particularly its role in placental dysfunction. Furthermore, this study highlights the significance of digital spatial profiling in mapping the intricate crosstalk between trophoblasts and villous core stromal cells, thus shedding light on pathways associated with placental dysfunction in pregnancies with SARS-CoV-2 infection.

Impact of Antenatal SARS-CoV-2 Exposure on SARS-CoV-2 Neutralization Potency

A pregnancy booster dose significantly reduces the risk and severity of COVID-19, and it is widely recommended. A prospective cohort study was conducted to compare the transplacental passage of maternal antibodies from vaccination or infection during three trimesters against both the vaccine-targeted Wuhan strain and the Omicron strain of SARS-CoV-2. Maternal-infant dyads from vaccinated mothers were collected between 6 June 2022 and 20 September 2022. We analyzed 38 maternal-infant dyads from mothers who had been infected with COVID-19 and 37 from mothers without any previous infection. Pregnant women who received their last COVID-19 vaccine dose in the third trimester exhibited the highest anti-spike protein antibody levels and neutralizing potency against both the Wuhan strain and Omicron BA.2 variant in their maternal and cord plasma. Both second- and third-trimester vaccination could lead to a higher level of neutralization against the Wuhan and Omicron strains. COVID-19 infection had a negative effect on the transplacental transfer ratio of SARS-CoV-2 antibodies. A booster dose during the second or third trimester is encouraged for the maximum transplacental transfer of humoral protection against COVID-19 for infants.

An Update on COVID-19-Associated Placental Pathologies

COVID-19 pregnancies are associated with increased rates of premature delivery and stillbirths. It is still a matter of debate whether there is a COVID-19-associated pattern of placenta pathology. We updated our previously published results on a systematic literature review and meta-analysis of COVID-19 pregnancies. In total, 38 reports on 3677 placentas were evaluated regarding histopathological changes. Maternal vascular malperfusion (32%), fetal vascular malperfusion (19%), acute and chronic inflammation (20% and 22%) were frequent pathologies. In non-COVID-19 pregnancies, placentas show similar histologic patterns and mainly similar frequencies of manifestation. It has to be taken into account that there might be an observation bias, because some findings are diagnosed as a "pathology" that might have been classified as minor or unspecific findings in non-COVID-19 placentas. COVID-19 placentitis occurs in 1-2% of cases at the most. In conclusion, this updated meta-analysis indicates that COVID-19 infection during pregnancy does not result in an increased rate of a specific placenta pathology and COVID-19 placentitis is rare.

Placental Transfer Efficiency of Neutralizing Antibodies on SARS-CoV-2 Vaccination before and after Pregnancy in Mexican Women

The protection of the neonate against pathogens depends largely on the antibodies transferred placentally from the mother; for this reason, maternal vaccination against emerging viruses, such as SARS-CoV-2, is of vital importance. Knowing some of the immunogenic factors that could alter the placental transfer of antibodies could aid in understanding the immune response and neonatal protection after maternal vaccination. In this study, we analyzed the efficiency of the placental transfer of binding and neutralizing antibodies, as well as some factors that could alter the passive immune response, such as the trimester of gestation at the time of immunization, the number of doses received by the mother and the type of vaccine. Binding IgG antibodies were detected by ELISA, and the detection of neutralizing antibodies was carried out using flow cytometry. Our results show efficient transfer rates (>1), which are higher when maternal vaccination occurs during the third trimester of gestation. Antibodies are detectable in mothers and their neonates after 12 months of maternal immunization, suggesting than the vaccination against COVID-19 before and during pregnancy in the Mexican population induces a lasting neutralizing response in mothers and their newborns.

Assessing the Impact of COVID-19 Vaccination on Preterm Birth: A Systematic Review with Meta-Analysis

During the coronavirus diseases 2019 (COVID-19) pandemic, the safety and efficacy of vaccination during pregnancy, particularly regarding the risk of preterm birth, have been a subject of concern. This systematic review aims to evaluate the impact of COVID-19 vaccination on preterm birth risk and to inform clinical practice and public health policies. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a database search included PubMed, Embase, and Scopus, conducted up until October 2023. Inclusion criteria focused on studies that examined COVID-19 vaccination during pregnancy and its correlation with preterm birth, defined as a birth before 37 weeks of gestation. Six studies met these criteria, encompassing 35,612 patients. A quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration's tool, with the risk of bias evaluated via a funnel plot analysis and an Egger's regression test. The studies demonstrated geographical diversity, mainly from Israel, Romania, and the United States, with a blend of prospective and retrospective designs. The patient cohort's mean age was 31.2 years, with common comorbidities such as gestational diabetes and obesity affecting 9.85% of the total population. The vaccination types varied across the studies, with BNT162b2 being the most used. The results indicated a low heterogeneity among the included studies, evidenced by a Cochran's Q statistic of 2.10 and an I2 statistic of 13%. The meta-analysis yielded a pooled odds ratio (OR) for a preterm birth risk post-vaccination of approximately 1.03 (95% CI: 0.82-1.30), suggesting no significant increase in preterm birth risk was associated with COVID-19 vaccination. Notable findings included a low preterm birth rate (as low as 0.6% and up to 6.1%) with minimal differences in neonatal outcomes, such as birth weight and APGAR (appearance, pulse, grimace, activity, and respiration) scores between vaccinated and unvaccinated groups. This study concludes that a COVID-19 vaccination during pregnancy does not significantly increase the risk of preterm birth. These findings are crucial for reassuring healthcare providers and pregnant women about the safety of COVID-19 vaccines and supporting their use in public health strategies during the pandemic.

SARS-CoV-2 neutralizing antibody titers in maternal blood, umbilical cord blood, and breast milk

OBJECTIVE

We quantified neutralizing SARS-CoV-2 antibody against spike protein (nAb) levels after vaccination and SARS-CoV-2 infection in maternal serum, cord blood, and breast milk and determined whether they correlate with levels of spike protein binding antibody.

STUDY DESIGN

Women (n = 100) were enrolled on admission for delivery. Previous SARS-CoV-2 infection was defined by anti-nucleocapsid antibodies. Levels of nAb and binding antibodies against spike receptor binding domain were measured in maternal blood, cord blood, and milk.

RESULTS

Maternal nAb levels were higher after vaccine and infection than vaccine alone but waned rapidly. Levels of nAb in cord blood and milk correlated with maternal levels and were higher in cord blood than maternal. Spike protein binding antibody levels correlated with nAb.

CONCLUSION

SARS-CoV-2 vaccination near delivery may boost antibody-mediated immunity in the peripartum period. Neutralizing antibodies are passed transplacentally and into milk. Spike protein binding antibody may be a feasible proxy for nAb.

Likely Vertical Transmission of Neonatal SARS CoV-2 Infection

Maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can affect placental function, but the possibility of intrauterine transmission has been debated. Several authors have published inclusion criteria for vertical transmission, but few reports exist that are able to meet the suggested requirements. Despite the fact that the majority of fetuses born to infected mothers do well, others become critically ill. We present a case of likely intrauterine transmission of a neonate born to a mother who was recently symptomatic with a positive SARS CoV-2 polymerase chain reaction (PCR). The parturient complained of decreased fetal movement and presented at 31 2/7 weeks' gestation with a biophysical profile score of 2/10 and required an emergency cesarean delivery. The neonate went on to develop severe leukopenia with signs of sepsis with a positive SARS CoV-2 PCR on day 4 of life and an otherwise pan-negative workup. Meeting criteria for transplacental transmission requires timely collection of several diagnostic studies that are not standard of care. Further research is needed to support the notion that intrauterine/transplacental infection is possible. Collection swabs should be obtained soon after delivery to help diagnose neonatal infection because early diagnosis is crucial to help identify opportunities for intervention.

A narrative review of COVID-19 vaccination in pregnancy and breastfeeding

The Coronavirus pandemic has affected millions of people due to the spread of the Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) virus. Pregnant individuals and infants are most vulnerable given the increased risk of developing severe complications from SARS-CoV-2 infection. Recently, COVID-19 vaccination is recommended for pregnant women and infants starting at 6 months of age to prevent disease contraction and minimize disease severity. We conducted a review of the literature on COVID-19 vaccination to discuss vaccine safety and efficacy, immunity after maternal vaccination, transplacental transfer and persistence of antibodies, and public health implications. Current evidence supports the safety and efficacy of vaccination during pregnancy. Maternal vaccination provides greater antibody persistence in infants compared to immunity from natural infection. Furthermore, vaccination has demonstrated an increased rate of passive antibody transfer through the placenta and breast milk. Public health interventions are important in achieving herd immunity and ultimately ending the pandemic. IMPACT: This article highlights the benefits of COVID-19 vaccination during pregnancy with a review of the data describing safety and efficacy, passive and active immunity after maternal immunization, trans-placental transfer and persistence of protective antibodies, and public health implications. With this information, healthcare providers can provide up-to-date knowledge to their pregnant patients to help them form an informed decision on vaccination and combat vaccine hesitancy.

Mechanisms of SARS-CoV-2 Placental Transmission

The widespread occurrence of SARS-CoV-2 infections and the diverse range of symptoms have placed significant strain on healthcare systems worldwide. Pregnancy has also been affected by COVID-19, with an increased risk of complications and unfavorable outcomes for expectant mothers. Multiple studies indicate that SARS-CoV-2 can infiltrate the placenta, breach its protective barrier, and infect the fetus. Although the precise mechanisms of intrauterine transmission remain unclear, factors such as perinatal infection, macrophages, sexual intercourse, and the virus' interaction with host angiotensin-converting enzyme 2 (ACE2) and neuropilin-1 (NRP-1) proteins appear to play a role in this process. The integrity of the placental barrier fluctuates throughout pregnancy and appears to influence the likelihood of fetal transmission. The expression of placental cell receptors, like ACE2, changes during pregnancy and in response to placental damage. However, due to the consistent presence of others, such as NRP-1, SARS-CoV-2 may potentially enter the fetus at different stages of pregnancy. NRP-1 is also found in macrophages, implicating maternal macrophages and Hofbauer cells as potential routes for viral transmission. Our current understanding of SARS-CoV-2's vertical transmission pathways remains limited. Some researchers question the ACE2-associated transmission model due to the relatively low expression of ACE2 in the placenta. Existing studies investigating perinatal transmission and the impact of sexual intercourse have either involved small sample sizes or lacked statistical significance. This review aims to explore the current state of knowledge regarding the potential mechanisms of COVID-19 vertical transmission, identifying areas where further research is needed to fill the gaps in our understanding.

Nanomedicine approaches against SARS-CoV-2 and variants

The world is grappling with the ongoing crisis of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), a global pandemic that continues to have a detrimental impact on public health and economies worldwide. The virus's relentless mutation has led to more transmissible, immune-evasive strains, thereby escalating the incidence of reinfection. This underscores the urgent need for highly effective and safe countermeasures against SARS-CoV-2 and its evolving variants. In the current context, nanomedicine presents an innovative and promising alternative to mitigate the impacts of this pandemic wave. It does so by harnessing the structural and functional properties at a nanoscale in a straightforward and adaptable manner. This review emphasizes the most recent progress in the development of nanovaccines, nanodecoys, and nanodisinfectants to tackle SARS-CoV-2 and its variants. Notably, the insights gained and strategies implemented in managing the ongoing pandemic may also offer invaluable guidance for the development of potent nanomedicines to combat future pandemics.

Maternal SARS-CoV-2 impacts fetal placental macrophage programs and placenta-derived microglial models of neurodevelopment

The SARS-CoV-2 virus activates maternal and placental immune responses, which in the setting of other infections occurring during pregnancy are known to impact fetal brain development. The effects of maternal immune activation on neurodevelopment are mediated at least in part by fetal brain microglia. However, microglia are inaccessible for direct analysis, and there are no validated non-invasive surrogate models to evaluate in utero microglial priming and function. We have previously demonstrated shared transcriptional programs between microglia and Hofbauer cells (HBCs, or fetal placental macrophages) in mouse models. Here, we assessed the impact of maternal SARS-CoV-2 on HBCs isolated from term placentas using single-cell RNA-sequencing. We demonstrated that HBC subpopulations exhibit distinct cellular programs, with specific subpopulations differentially impacted by SARS-CoV-2. Assessment of differentially expressed genes implied impaired phagocytosis, a key function of both HBCs and microglia, in some subclusters. Leveraging previously validated models of microglial synaptic pruning, we showed that HBCs isolated from placentas of SARS-CoV-2 positive pregnancies can be transdifferentiated into microglia-like cells, with altered morphology and impaired synaptic pruning behavior compared to HBC models from negative controls. These findings suggest that HBCs isolated at birth can be used to create personalized cellular models of offspring microglial programming.

Impacts of the COVID-19 pandemic on early pregnancy outcomes among women undergoing frozen-thawed embryo transfer: a retrospective cohort study

The effect of COVID-19 pandemic on early pregnancy outcomes among women undergoing frozen-thawed embryo transfer (FET) remains unclear. We aimed to evaluate whether early pregnancy outcomes were altered in patients undergoing FET during the pandemic. In this retrospective cohort study, women conceived through FET in 2016-2021 from two hospitals in China were included. The early pregnancy outcomes were compared using Logistic regression model, including biochemical pregnancy rate (BPR), clinical pregnancy rate (CPR), and early pregnancy loss rate (EPLR). A total of 16,669 (67.2%) and 6,113 (26.8%) FET cycles enrolled before and during the pandemic, respectively. Univariate analyses showed that women undergoing FET during the pandemic had significantly increased BPR (72.9% vs. 69.7%) and CPR (59.5% vs. 55.0%), and significantly decreased EPLR (13.7% vs. 16.7%) compared to pre-pandemic (all P < 0.001). Moreover, after adjustment, the results were in accordance with univariate analysis for CPR [adjusted OR (95%CI) = 1.08 (1.01-1.14)] and EPLR [adjusted OR (95%CI) = 0.82 (0.73-0.91)], while the statistical significance between BPR and the pandemic disappeared. In summary, women conceived by FET did not have a reduced possibility of clinical pregnancy and a higher risk of early pregnancy loss during the pandemic compared with the pre-pandemic.

Immunomodulation of Antibody Glycosylation through the Placental Transfer

Establishing an immune balance between the mother and fetus during gestation is crucial, with the placenta acting as the epicenter of immune tolerance. The placental transfer of antibodies, mainly immunoglobulin G (IgG), is critical in protecting the developing fetus from infections. This review looks at how immunomodulation of antibody glycosylation occurs during placental transfer and how it affects fetal health. The passage of maternal IgG antibodies through the placental layers, including the syncytiotrophoblast, stroma, and fetal endothelium, is discussed. The effect of IgG subclass, glycosylation, concentration, maternal infections, and antigen specificity on antibody transfer efficiency is investigated. FcRn-mediated IgG transport, influenced by pH-dependent binding, is essential for placental transfer. Additionally, this review delves into the impact of glycosylation patterns on antibody functionality, considering both protective and pathological effects. Factors affecting the transfer of protective antibodies, such as maternal vaccination, are discussed along with reducing harmful antibodies. This in-depth examination of placental antibody transfer and glycosylation provides insights into improving neonatal immunity and mitigating the effects of maternal autoimmune and alloimmune conditions.

SARS-CoV-2 Infection in Late Pregnancy and Childbirth from the Perspective of Perinatal Pathology

This review focuses on SARS-CoV-2 infection in placental and fetal tissues. Viremia is rare in infected pregnant women, and the virus is seldom amplified from placental tissues. Definite and probable placental infection requires the demonstration of viral RNA or proteins using in situ hybridization (ISH) and immunohistochemistry (IHC). Small subsets (1.0-7.9%, median 2.8%) of placentas of SARS-CoV-2-positive women showed definite infection accompanied by a characteristic histopathology named SARS-CoV-2 placentitis (SP). The conventionally accepted histopathological criteria for SP include the triad of intervillositis, perivillous fibrin deposition, and trophoblast necrosis. SP was shown to be independent of the clinical severity of the infection, but associated with stillbirth in cases where destructive lesions affecting more than 75% of the placental tissue resulted in placental insufficiency and severe fetal hypoxic-ischemic injury. An association between maternal thrombophilia and SP was shown in a subset of cases, suggesting a synergy of the infection and deficient coagulation cascade as one of the mechanisms of the pathologic accumulation of fibrin in affected placentas. The virus was amplified from fetal tissues in approximately 40% of SP cases, but definite fetal involvement demonstrated using ISH or IHC is exceptionally rare. The placental pathology in SARS-CoV-2-positive women also includes chronic lesions associated with placental malperfusion in the absence of definite or probable placental infection. The direct viral causation of the vascular malperfusion of the placenta in COVID-19 is debatable, and common predispositions (hypertension, diabetes, and obesity) may play a role.

Assessment of fetal myocardial performance index in pregnant women with SARS-CoV-2 infection: A prospective cohort study

OBJECTIVES

Our aim was to investigate the effects of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on fetal myocardial performance in women who had it during their pregnancy.

MATERIALS AND METHODS

In our prospective cohort study including healthy pregnant women and pregnant with SARS-CoV-2 infection, we collected patients' data between June 2021 and April 2022. Maternal characteristics, gestational age at SARS-CoV-2 infection and ultrasound examination, and body mass index were noted. Fetal biometry, fetal anatomy scanning, placenta, amniotic fluid index (AFI), and Doppler parameters were routinely examined in all patients. Left ventricular myocardial performance index (MPI) was measured during fetal echocardiography examination. Doppler parameters, AFI, and MPI values were compared between two groups.

RESULTS

Compared with the control group (n = 80), MPI values were found within normal limits in fetuses of pregnant women with SARS-CoV-2 infection (n = 80) (MPI: 0.38 ± 0.06 in the control groups vs. 0.39 ± 0.05 in the SARS-COV-2 positive group, p = 0.79). There was no relationship between SARS-CoV-2 infection and changes in AFI and umbilical artery pulsatility index (PI) values. Uterine artery PI values were significantly higher in pregnant women with (SARS-CoV-2) infection (0.81 in the control group vs. 0.97 in the SARS-CoV-2 group, p < 0.05).

CONCLUSIONS

Fetal cardiac functions were not affected in pregnant women with previous (SARS-CoV-2) infection. Further metaanalyses are warranted to confirm the results.

Association between maternal coronavirus disease 2019 and transient tachypnea of the newborn: a single-center study

BACKGROUND

Limited clinical reports have investigated the effects of maternal coronavirus disease 2019 (COVID-19) on fetuses and neonates.

PURPOSE

This retrospective study aimed to assess the impact of maternal COVID-19 on neonates during the perinatal period, including neonatal clinical outcomes, versus the outcomes of neonates of mothers without COVID-19.

METHODS

Neonates born to COVID-19-infected mothers at the National Health Insurance Service Ilsan Hospital between February 2021 and March 2022 were included. Those with gestational age (GA) ≥35+0 weeks who were born within 2 weeks of the maternal infection were matched 1:2 with a control group based on GA. The main outcomes were respiratory diseases, including transient tachypnea of the newborn (TTN), respiratory distress syndrome, meconium aspiration syndrome, the need for respiratory support, and length of hospital stay. Uni- and multivariate logistic regression analyses were performed and adjusted for relevant covariates, including maternal age, obstetric complications (hypertension and gestational diabetes), delivery mode, birth weight, sex, and small-for-gestational-age status.

RESULTS

The case group comprised 103 neonates (mean GA, 38.5±1.3 weeks; mean birth weight, 3,121±397 g), while the control group included 206 neonates (mean GA, 38.4±1.2 weeks; mean birth weight, 3088±428 g). In the case and control groups, the proportion of cesarean sections was 91% and 40%, respectively, while the proportion of male infants was 56% and 47%, respectively. After adjusting for covariates, the case group had a higher risk of TTN (adjusted odd ratio [AOR], 3.69; 95% confidence interval [CI], 1.69-8.07), noninvasive respiratory ventilator use (AOR, 2.28; 95% CI, 1.05-4.97), and oxygen support (AOR, 4.83; 95% CI, 1.46-15.95).

CONCLUSION

Newborns born to COVID-19-infected mothers are at increased risk of TTN and may require respiratory support. Close monitoring of respiratory symptoms is crucial in neonates.

Investigating the impact of Sinopharm COVID-19 vaccination on antibody response in pregnant women and their newborns

This study aims to investigate the levels of receptor-binding domain (RBD), spike, and neutralizing antibodies in pregnant women who received the Sinopharm vaccine and their newborns. A cross-sectional study was conducted at a tertiary center, Mashhad, Iran. We included 88 pregnant women who had received at least two doses of the Sinopharm vaccine. Maternal and umbilical cord blood samples taken at delivery were analyzed for antibodies using ELISA tests. Antibody levels did not vary significantly between women with two or three vaccine doses. Only 1.1% of mothers had undetectable levels of RBD antibodies, but detectable antibodies were observed in all newborns. A significant linear correlation was found between the levels of neutralizing antibodies (r = 0.7, p < 0.001) and RBD antibodies (r = 0.833, p < 0.001) in mothers and their newborns, but not for Spike antibodies (r = 0.214, p = 0.045). In mothers, high titers of antispike and RBD antibodies were observed at the time of delivery. The high titers of RBD and antispike antibodies were found in cord blood, suggesting potential neonatal immunity. Detectable levels of antibodies were found in both groups, regardless of the timing of vaccination. The Sinopharm vaccine generates detectable levels of antibodies in pregnant women, which are efficiently transferred to their newborns. The number of vaccine doses (two or three) did not significantly impact the levels of detectable antibodies. This underscores Sinopharm's potential efficacy in protecting pregnant women and their infants from COVID-19.

Comparison of Anti-SARS-CoV-2-Specific Antibody Signatures in Maternal and Infant Blood after COVID-19 Infection versus COVID-19 Vaccination during Pregnancy

OBJECTIVE

 The Advisory Committee on Immunization Practices and The American College of Obstetricians and Gynecologists recommend coronavirus disease 2019 (COVID-19) vaccine for pregnant persons to prevent severe illness and death. The objective was to examine levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) IgG, IgM, and IgA against spike protein receptor binding domain (RBD) and nucleocapsid protein (NCP) in maternal and infant/cord blood at delivery after COVID 19 vaccination compared with SARS-CoV-2 infection at in mother-infant dyads at specified time points.

STUDY DESIGN

 Mothers with SARS-CoV-2 infection (n = 31) or COVID-19 vaccination (n = 25) during pregnancy were enrolled between July 2020 and November 2021. Samples were collected at delivery and IgG, IgM, and IgA to RBD of spike and NCPs compared in the infected and vaccinated groups. Timing of infection/vaccination prior to delivery and correlation with antibody levels was performed.

RESULTS

 The majority of participants received vaccination within 90 days of delivery and over half received the Pfizer BioNTech vaccine. There were no significant correlations between antibody levels and timing of infection or vaccination. Infant IgG levels to the RBD domain of spike protein were higher in the vaccinated group (n = 25) as compared with the infants born to mothers with infection (n = 31). Vaccination against COVID-19 during pregnancy was associated with detectable maternal and infant anti-RBD IgG levels at delivery irrespective of the timing of vaccination.

CONCLUSION

 Timing of vaccination had no correlation to the antibody levels suggesting that the timing of maternal vaccination in the cohort did not matter. There was no IgM detected in infants from vaccinated mothers. Infants from vaccinated mothers had robust IgG titers to RBD, which have a lasting protective effect in infants.

KEY POINTS

· COVID-19 vaccination during pregnancy had detectable antibody.. · No correlation between antibody levels and timing of vaccination.. · Infants from vaccinated mothers had robust IgG titers to RBD..

Cytokine responses to SARS-COV2 infection in mother-infant dyads: a systematic review and meta-analysis

Background

The COVID-19 pandemic has affected a significant number of pregnant women worldwide, but studies on immune responses have presented conflicting results. This study aims to systematically review cytokine profiles in pregnant women with SARS-CoV-2 infection and their infants to evaluate immune responses and potential transplacental transfer of cytokines.

Materials and methods

A comprehensive search of 4 databases was conducted to identify relevant studies. Inclusion criteria included studies measuring individual cytokines in pregnant women and/or their neonates. Studies were evaluated for quality, and data were extracted for analysis. Meta-analyses were performed using the random-effects model.

Results

Seventeen studies met the inclusion criteria, including data from 748 pregnant women and 287 infants. More than three of these studies evaluated data of 20 cytokines in maternal serum, and data of 10 cytokines was available from cord blood samples. Only the serum level of CXCL10 was significantly up-regulated in SARS-CoV-2 positive pregnant women (n = 339) compared to SARS-CoV-2 negative pregnant women (n = 409). Subset analysis of maternal samples (n = 183) collected during the acute phase of COVID-19 infection showed elevated CXCL10 and IFN-γ. No significant differences in cytokine levels were found between cord blood samples collected from infants born to mothers with (n = 97) and without (n = 190) COVID-19 during gestation. Subset analysis of cord blood samples collected during the acute phase of maternal infection was limited by insufficient data. The heterogeneity among the studies was substantial.

Conclusion

The findings suggest that maternal cytokines responses to SARS-CoV-2 infection during pregnancy are not significantly dysregulated, except for CXCL10 and IFN-γ during the acute phase of illness. No evidence of increased cytokine levels in cord blood samples was observed, although this could be impacted by the time period between initial maternal infection and cord blood collection. These results provide some reassurance to parents and healthcare providers but should be interpreted cautiously due to study variations and limitations.

The influence of SARS-CoV-2 on the immune system elements and on the placental structure. Clinical, histological and immunohistochemical study

BACKGROUND

The effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy remain relatively unknown.

AIM

We present this original paper where we analyzed 60 parturients, at term, 30 without associated infection (C-) and 30 with associated infection (C+), present at birth.

METHODS

We analyzed the blood count and placental microscopic structure through classical and immunohistochemical staining and observed the placental areas affected by the presence of SARS-CoV-2.

RESULTS

SARS-CoV-2 infection was accompanied by a decrease in the number of lymphocytes, the number of platelets and the presence of placental structural changes, identifying extensive areas of amyloid deposits, placental infarcts, vascular thrombosis, syncytial knots, with a decrease in placental vascular density and the presence of infection in the cells located at decidual level, at syncytiotrophoblast level and at the level of the cells of the chorionic plate, still without overcoming this barrier and without causing any fetal infection in the analyzed cases.

CONCLUSIONS

This study shows that the invasion of SARS-CoV-2 in the placenta can produce significant structural changes, with a decrease in placental vascular density that can have significant implications on proper fetal perfusion. Also, the presence of immunoreactivity at the level of decidua, the placental villi, as well as the chorionic plate proves that the virus can overcome the maternal-fetal barrier. However, in the analyzed cases there were no fetal infections at birth, which may show that local placental factors can be a protective filter for the fetus.

Clinical outcomes and antibody transfer in a cohort of infants with in utero or perinatal exposure to SARS-CoV-2 (Coronascope Study)

We aimed to describe the outcomes, focusing on the hearing and neurological development, of infants born to mothers with COVID-19 during pregnancy and to evaluate the persistence of maternal antibodies in the first months of life. An observational, prospective study at a tertiary hospital in Madrid (Spain) on infants born to mothers with COVID-19 during pregnancy between March and September 2020 was conducted. A follow-up visit at 1-3 months of age with a physical and neurological examination, cranial ultrasound (cUS), SARS-CoV-2 RT-PCR on nasopharyngeal swab, and SARS-CoV-2 serology were performed. Hearing was evaluated at birth through the automated auditory brainstem response and at six months of age through the auditory steady-state response. A neurodevelopmental examination using the Bayley-III scale was performed at 12 months of age. Of 95 infants studied, neurological examination was normal in all of them at the follow-up visit, as was the cUS in 81/85 (95%) infants, with only mild abnormalities in four of them. Serology was positive in 47/95 (50%) infants, which was not associated with symptoms or severity of maternal infection. No hearing loss was detected, and neurodevelopment was normal in 96% of the infants (median Z score: 0).

CONCLUSION

In this cohort, the majority of infants born to mothers with COVID-19 during pregnancy were healthy infants with a normal cUS, no hearing loss, and normal neurodevelopment in the first year of life. Only half of the infants had a positive serological result during the follow-up.

WHAT IS KNOWN

• Hearing loss and neurodevelopmental delay in infants born to mothers with COVID-19 during pregnancy has been suggested, although data is inconsistent. Maternal antibody transfer seems to be high, with a rapid decrease during the first weeks of life.

WHAT IS NEW

• Most infants born to mothers with COVID-19 during pregnancy had normal hearing screening, cranial ultrasound, and neurodevelopmental status at 12 months of life. Antibodies against SARS-CoV-2 were only detected in 50% of the infants at two months of life.

The impact of trimester of COVID-19 infection on pregnancy outcomes after recovery

OBJECTIVES

Many physiological adaptations occur during pregnancy. It is not currently known how timing of COVID-19 infection impacts pregnancy. We hypothesize that maternal and neonatal outcomes are different if COVID-19 infection occurs in different trimesters of pregnancy.

METHODS

This retrospective cohort study was conducted from 3/2020 to 6/2022. Pregnant patients with a positive COVID-19 infection more than 10 days before delivery (COVID-recovered) were identified and grouped by trimester of infection. Demographics and maternal, obstetric, and neonatal outcomes were analyzed. ANOVA, Wilcoxon rank-sum test, Pearson's chi-squared test, and Fisher's exact test were used to compare continuous and categorical data.

RESULTS

A total of 298 COVID-recovered pregnant patients were identified. Of those, 48 (16 %) were infected in the 1st trimester, 123 (41 %) in the 2nd, and 127 (43 %) in the 3rd. There were no significant demographic differences between the study groups. Vaccination status was similar. Hospital admission rate and the need for oxygen therapy while infected were significantly higher in patients with 2nd or 3rd trimester infection (18 % & 20 % vs. 2 % and 13 % & 14 % vs. 0 %, respectively). Rates of preterm birth (PTB) and extreme PTB were higher in the 1st trimester infection group. Infants born to mothers infected in the 2nd trimester had more neonatal sepsis workups (22 % vs. 12 % & 7 %). Other outcomes were similar between groups.

CONCLUSIONS

First trimester COVID-recovered patients were more likely to have a preterm birth despite having lower rates of hospital admission and oxygen supplementation while infected than patients who recovered from a 2nd or 3rd trimester infection.

Accelerated Longitudinal Weight Gain Among Infants With In Utero COVID-19 Exposure

CONTEXT

Since the initial outbreak of coronavirus disease 2019 (COVID-19), a novel population of children with in utero exposure to maternal infection has emerged whose health outcomes are largely unknown.

OBJECTIVE

To compare longitudinal growth trajectories among infants with vs without in utero COVID-19 exposure.

METHODS

We conducted a longitudinal cohort study leveraging a prospectively enrolled perinatal biorepository among 149 infants with in utero COVID-19 exposure and 127 unexposed controls. Weight, length, and body mass index (BMI) were abstracted from health records at 0, 2, 6, and 12 months and standardized using World Health Organization growth charts. Analyses were adjusted for maternal age, ethnicity, parity, insurance, and BMI as well as infant sex, birthdate, and breastfeeding.

RESULTS

Infants with in utero COVID-19 exposure vs controls exhibited differential trajectories of weight and BMI, but not length, z-score over the first year of life (study group × time interaction, P < .0001 for weight and BMI). Infants born to mothers with prenatal COVID-19 had lower BMI z-score at birth (effect size: -0.35, 95% CI -0.66 to -0.03) and greater gain in BMI z-score from birth to 12 months (effect size: 0.53, 95% CI 0.06 to 0.99). Birth weight z-score mediated a significant proportion of the relationship between COVID-19 exposure and postnatal growth (estimate ± SE, 32 ± 14%, P = .02).

CONCLUSION

Infants with in utero COVID-19 exposure exhibited lower birth weight and accelerated weight gain in the first year of life, which may be harbingers of downstream cardiometabolic pathology. Further studies are needed to delineate cardiometabolic sequelae among this emerging global population.

Balance between maternal antiviral response and placental transfer of protection in gestational SARS-CoV-2 infection

The intricate interplay between maternal immune response to SARS-CoV-2 and the transfer of protective factors to the fetus remains unclear. By analyzing mother-neonate dyads from second and third trimester SARS-CoV-2 infections, our study shows that neutralizing antibodies (NAbs) are infrequently detected in cord blood. We uncovered that this is due to impaired IgG-NAb placental transfer in symptomatic infection and to the predominance of maternal SARS-CoV-2 NAbs of the IgA and IgM isotypes, which are prevented from crossing the placenta. Crucially, the balance between maternal antiviral response and transplacental transfer of IgG-NAbs appears to hinge on IL-6 and IL-10 produced in response to SARS-CoV-2 infection. In addition, asymptomatic maternal infection was associated with expansion of anti-SARS-CoV-2 IgM and NK cell frequency. Our findings identify a protective role for IgA/IgM-NAbs in gestational SARS-CoV-2 infection and open the possibility that the maternal immune response to SARS-CoV-2 infection might benefit the neonate in 2 ways, first by skewing maternal immune response toward immediate viral clearance, and second by endowing the neonate with protective mechanisms to curtail horizontal viral transmission in the critical postnatal period, via the priming of IgA/IgM-NAbs to be transferred by the breast milk and via NK cell expansion in the neonate.

Skin-to-skin contact in mothers with suspected, probable, or confirmed COVID-19

BACKGROUND

The World Health Organization recommends skin-to-skin contact (SSC) in newborns of mothers with COVID-19, applying infection prevention and control measures, and after a process of antenatal counseling on the possible risks and benefits. In this study, the reasons given for and against postnatal SSC in mothers with COVID-19 were reviewed.

METHOD

Between November and December 2020, we conducted a scoping review. Twenty-six relevant studies were identified. The results were extracted and presented narratively.

RESULTS

The reasons described for avoiding SSC have include contradictory recommendations, risk of virus transmission, impossibility of universal antepartum maternal screening for COVID-19, work overload, and ethical considerations. The reasons given for the maintenance of SSC include maternal and infant benefits of SSC, previous experiences in viral outbreaks, protection of newborns against infections, decreased contact with professionals, caregivers and surfaces, and preservation of natural processes.

CONCLUSIONS

The recommendation to allow SSC is based primarily on the acceptance that horizontal perinatal transmission is unlikely if correct hygiene precautions are taken and that the benefits of SSC outweigh the potential risks of neonatal COVID-19 infection. Knowing the reasons that have motivated the current recommendations on SSC is essential to be able to carry out an effective prenatal parental education that allows a shared decision to be made.

Siglecs family used by pathogens for immune escape may engaged in immune tolerance in pregnancy

The Siglecs family is a group of type I sialic acid-binding immunoglobulin-like receptors that regulate cellular signaling by recognizing sialic acid epitopes. Siglecs are predominantly expressed on the surface of leukocytes, where they play a crucial role in regulating immune activity. Pathogens can exploit inhibitory Siglecs by utilizing their sialic acid components to promote invasion or suppress immune functions, facilitating immune evasion. The establishing of an immune-balanced maternal-fetal interface microenvironment is essential for a successful pregnancy. Dysfunctional immune cells may lead to adverse pregnancy outcomes. Siglecs are important for inducing a phenotypic switch in leukocytes at the maternal-fetal interface toward a less toxic and more tolerant phenotype. Recent discoveries regarding Siglecs in the reproductive system have drawn further attention to their potential roles in reproduction. In this review, we primarily discuss the latest advances in understanding the impact of Siglecs as immune regulators on infections and pregnancy.

Serologic evolution and follow-up to IgG antibodies of infants born to mothers with gestational COVID

BACKGROUND

It is known that SARS-CoV-2 antibodies from pregnant women with SARS-CoV-2 infection during pregnancy cross the placenta but the duration and the protective effect of these antibodies in infants is scarce.

METHODS

This prospective study included mothers with SARS-COV-2 infection during pregnancy and their infants from April 2020 to March 2021. IgG antibodies to SARS-CoV-2 spike protein were performed on women and infants at birth and at two and six months during follow-up. Anthropometrical measures and physical and neurological examinations and a clinical history of symptoms and COVID-19 diagnosis were collected. Simple linear regression was performed to compare categorical and continuous variables. To compare the mother's and infant's antibody titers evolution, a mixed linear regression model was used. A predictive model of newborn antibody titers at birth has been established by means of simple stepwise linear regression.

RESULTS

51 mother-infant couples were included. 45 (90%) of the mothers and 44 (86.3%) of the newborns had a positive serology al birth. These antibodies were progressively decreasing and were positive in 34 (66.7%) and 7 (13.7%) of infants at 2 and 6 months, respectively. IgG titers of newborns at birth were related to mothers' titers, with a positive moderate correlation (Pearson's correlation coefficient: 0.82, p < 0,001). Fetal/maternal antibodies placental transference rate was 1.3 (IQR: 0.7-2.2). The maternal IgG titers at delivery and the type of maternal infection (acute, recent, or past infection) was significantly related with infants' antibody titers at birth. No other epidemiological or clinical factors were related to antibodies titers. Neurodevelopment, psychomotor development, and growth were normal in 94.2% of infants in the third follow-up visit. No infants had a COVID-19 diagnosis during the follow-up period.

CONCLUSIONS

Transplacental transfer of maternal antibodies is high in newborns from mothers with recent or past infection at delivery, but these antibodies decrease after the first months of life. Infant's IgG titers were related to maternal IgG titers at delivery. Further studies are needed to learn about the protective role of maternal antibodies in infants.

Shadow of a Pandemic: Persistence of Prenatal SARS-CoV-2 Antibodies in Newborn Blood Spots

To investigate COVID-19 surveillance among pregnant women, the California Genetic Disease Screening Program conducted a screening performance and seroprevalence evaluation of maternal SARS-CoV-2 antibodies detected in banked newborn dried blood spots (DBS). We obtained seropositive results for 2890 newborn DBS from cohorts in 2020 and 2021 using Enable Bioscience's Antibody Detection by Agglutination-PCR (ADAP) assay for SARS-CoV-2 antibodies. To infer maternal infection, we linked 312 women with a known laboratory-confirmed COVID-19 episode with their newborn's DBS SARS-CoV02 antibody result. Among 2890 newborns, we detected 453 (15.7%) with SARS-CoV-2 antibodies in their DBS. Monthly snapshot statewide seroprevalence among neonates was 12.2% (95% CI 10.3-14.1%, n =1156) in December 2020 and 33.3% (95% CI 29.1-37.4%, n = 26) in March 2021. The longest time recorded from COVID-19 infection to a seropositive neonatal result was 11.7 months among the 312 mothers who had an available SARS-CoV-2 PCR test result. Approximately 94% (153/163) of DBS were seropositive when a known maternal infection occurred earlier than 19 days before birth. The estimated relative sensitivity of DBS to identify prevalent maternal infection was 85.1%, specificity 98.5% and PPV 99.2% (n = 312); the sensitivity was lowest during the December 2021 surge when many infections occurred within 19 days of birth. Fifty pre-pandemic specimens (100% seronegative) and 23 twin-pair results (100% concordant) support an intrinsic specificity and PPV of ADAP approaching 100%. Maternal infection surveillance is limited by a time lag prior to delivery, especially during pandemic surges.