Enninga, Elizabeth Ann L

Introduction Placental inflammation is a major contributor to preterm birth (PTB), and there are currently few targeted strategies to prevent PTB and its associated adverse neonatal outcomes. Serum amyloid A (SAA), particularly the isoforms SAA1 and SAA2, are well-recognized inflammatory markers, but their functional roles in placental inflammation remain poorly defined. Methods Using a translational mouse model of sub-chronic maternal inflammation, we investigated the immune mechanisms and therapeutic potential of siRNA-mediated targeting of Saa2 (siSaa2). Placental expression patterns of SAA2 were examined in vivo , and macrophage responses to extracellular SAA2 were modeled in vitro using RAW264.7 cells to assess downstream P2X7R-dependent signaling and functional outcomes. Results SAA2 is primarily induced in placental trophoblast and endothelial compartments during inflammation, where it acts as an extracellular inflammatory mediator. In vitro , we model macrophage responses to extracellular SAA2 using RAW264.7 cells to examine downstream P2X7R-dependent signaling and functional outcomes. Maternal administration of siSaa2 improved PTB rates, placental morphology and fetal brain development. Additionally, SAA1 and SAA2 exhibited distinct expression patterns in the mouse and human placenta. Discussion These findings identify placental SAA2 as a key inflammatory mediator in inflammation-associated PTB and demonstrate that targeted silencing of Saa2 represents a potential therapeutic strategy to mitigate placental injury and adverse fetal outcomes.

ABSTRACT Objective Fetal surgery (FS) for spina bifida (SB) repair improves infant outcomes; however, spontaneous preterm birth (sPTB) is common. We aimed to evaluate maternal and fetal immune responses following FS for SB repair. Method Pregnant participants undergoing fetoscopic SB repair at 24–26 weeks of gestational age (GA) were prospectively recruited and compared to GA matched low‐risk controls. Blood samples were collected at baseline, 2‐week post‐surgery (POD14), and delivery. Cytokine analysis, flow cytometry, and T cell receptor (TCR) sequencing were performed. Results sPTB occurred in 5/6 of the FS group (0/6 of controls). Maternal blood in the FS group demonstrated increased alpha‐fetoprotein (AFP) and anti‐inflammatory IL‐1RA at baseline and POD14, increased pro‐inflammatory IL‐8 only post‐operatively, and elevated growth factors throughout. T cell phenotypes following FS revealed reduced TH17 frequency but increased activation receptors on cytotoxic T cells. At delivery, the FS cohort had reduced Th2 and Th17 helper T cells and CD4+ memory T cells, but CD8 T cells still showed increased activation. No TCR expansion was detected post‐surgery, suggesting antigen‐independent activation. Cord blood in FS repaired neonates had increased AFP, IL‐8, IL‐1RA. Conclusion Systemic immune changes following FS, particularly T cell maturation and activation, were observed. Further characterization of these mechanisms may help predict and prevent surgery‐induced PTB, improving outcomes.

Abstract Obstetric training programs typically offer limited formal education on placental pathology; yet, in practice, obstetric providers are expected to incorporate placental pathology findings into the overall evaluation of obstetric complications. In this narrative review, we briefly review pathology classifications and then delve deeper into pathology findings that may change clinical decision‐making, specifically highlighting pathologic lesions with a recurrence risk and recommended management for subsequent pregnancies. Last, we present specific recommendations on how to improve clinical interpretability and utility of placental pathology reports for obstetrical practice.

Withdrawal Statement The authors have withdrawn the manuscript because the data it contained has been updated. Consequently, they request that this work should not be cited as a reference for any projects to ensure the use of the most current information. For any questions or further clarifications, readers are encouraged to contact the corresponding author directly

The placenta is susceptible to infection by a number of viral pathogens, including severe acute respiratory syndrome coronavirus 2, which is associated with poor fetal outcomes. The histologic pattern of injury, termed severe acute respiratory syndrome coronavirus 2 placentitis, is characterized by a triad of increased perivillous fibrin deposition, intervillous histiocytes, and trophoblast necrosis. While the etiology of massive perivillous fibrin deposition (MPVFD) is mostly unknown, previous case reports of MPVFD in association with maternal Enterovirus (ENT) suggest that a subset of these cases are a consequence of undiagnosed viral infection. We evaluated 46 placentas collected between 2011 and 2022 with a diagnosis of MPVFD (n = 41) or chronic histiocytic intervillositis (CHI; n = 4). Combining methods of pan-viral metagenomic sequencing and targeted viral PCR, we detected Enterovirus DNA in 8 of 45 (18%) MPVFD and/or CHI cases. Seven of these positive cases were from MPVFD, and 1 was associated with a CHI diagnosis. Enterovirus A species (n = 7) were commonly identified, whereas one case had Enterovirus B. Histologic evaluation of these cases, including immunohistochemical staining for CD68, demonstrated increased intervillous histiocytes in Enterovirus-positive MPVFD cases in comparison with Enterovirus -negative, as well as evidence of trophoblast necrosis. Thus, we favor the terminology Enterovirus placentitis to describe this pathology. Overall, these findings suggest that Enterovirus is an underrecognized etiology of histologic MPVFD and, possibly, CHI. Further study to evaluate the recurrence risk of Enterovirus placentitis in comparison to MPVFD may help inform future fertility planning in patients with these diagnoses.

ObjectivesFetal growth restriction (FGR) is commonly associated with placental dysfunction, increasing perinatal morbidity and mortality. Visualizing placental vessels in utero would be advantageous for identifying functional FGR cause and determining proper management strategies. We aimed to utilize high‐sensitivity ultrasound microvessel imaging (HUMI) for quantifying placental vessel density (VD) in pregnancies diagnosed with FGR.MethodsThis pilot case–control study enrolled subjects in the third trimester with a diagnosis of FGR (n = 40) and gestational age‐matched controls with normal fetal growth (n = 20) at a 2:1 ratio, respectively. The Verasonics Vantage ultrasound system was used to perform HUMI on each participant at one timepoint. Scanning involved randomized singular value decomposition‐based clutter filtering to identify the villous tree, followed by step‐by‐step scanning to acquire 3‐dimensional‐like data. Mean VD was calculated from three ultrasound measurements per subject. Additional clinical and pathology data were also collected and compared.ResultsSixteen participants were utilized to establish the scanning protocol and 2 met exclusion criteria at delivery. Thus, VD was successfully measured on 42 pregnancies scanned at 35 weeks 5 days on average. In FGR (n = 24), placental VD was significantly reduced compared to controls (P < .01). VD measures were as good at predicting FGR as systolic/diastolic (S/D) ratios (area under the curve 0.86 versus 0.80). In a smaller cohort, VD in placentas with a diagnosis of inflammatory villitis (n = 10) by histology showed an increase in VD compared to those without inflammation (P = .01). Low VD was correlated with increased S/D ratios (P = .03).ConclusionsHUMI is useful for identifying altered placental vascularization in utero for FGR. VD may be a valuable indicator for placental health and could lead to improved risk stratification methods considering underlying biology.

Objective To evaluate maternal risk factors associated with chronic villitis of unknown etiology (VUE) and to describe cooccurring placental pathologies. Study Design A retrospective case–control study was conducted using placental pathology records from deliveries ≥ 20 weeks between 2010 and 2018. Cases were placentas with documented chronic villitis without infectious cause, hereafter called VUE. Controls were placentas without this diagnosis, matched to the cases 2:1. Maternal and neonatal demographic and clinical data were collected. Descriptive statistics are reported with Fisher's exact test or a chi-squared test, as appropriate, and multivariable conditional logistic regression was conducted. Results Our study included 352 cases with VUE and 657 controls. A diagnosis of gestational diabetes (p = 0.03) and gestational hypertension (p = 0.06) was 1.5 times more likely to occur in those with a VUE diagnosis. A trend was also seen for chronic hypertension (odds ratio [OR] = 1.7, p = 0.07) and preeclampsia (OR = 1.5, p = 0.09) compared with controls. Placentas with VUE, specifically high-grade VUE, were more likely to be small for gestational age (p = 0.01), and to be diagnosed with other placental findings including lymphoplasmacytic or chronic deciduitis (p < 0.01), maternal (p < 0.01) and fetal vascular malperfusion (p = 0.02), and chorionitis (acute or chronic; p < 0.01). Conclusion Gestational diabetes and hypertension were associated with a diagnosis of VUE, and overall, VUE placentas have more abnormal placental findings compared with control. Understanding VUE risk factors may facilitate prenatal care strategies and counseling to achieve the best outcomes for pregnant patients and their neonates. Key Points

Abstract Despite intensive characterization of immune responses after COVID-19 infection and vaccination, research examining protective correlates of vertical transmission in pregnancy are limited. Herein, we profiled humoral and cellular characteristics in pregnant women infected or vaccinated at different trimesters and in their corresponding newborns. We noted a significant correlation between spike S1–specific IgG antibody and its RBD-ACE2 blocking activity (receptor-binding domain–human angiotensin-converting enzyme 2) in maternal and cord plasma (P &lt; .001, R &gt; 0.90). Blocking activity of spike S1–specific IgG was significantly higher in pregnant women infected during the third trimester than the first and second trimesters. Elevated levels of 28 cytokines/chemokines, mainly proinflammatory, were noted in maternal plasma with infection at delivery, while cord plasma with maternal infection 2 weeks before delivery exhibited the emergence of anti-inflammatory cytokines. Our data support vertical transmission of protective SARS-CoV-2–specific antibodies. This vertical antibody transmission and the presence of anti-inflammatory cytokines in cord blood may offset adverse outcomes of inflammation in exposed newborns.

Congenital rubella syndrome is a constellation of birth defects that can have devastating consequences, impacting approximately 100,000 births worldwide each year. The incidence is much lower in countries that routinely vaccinate their population. In the US, postnatal immunization of susceptible women is an important epidemiological strategy for the prevention of rubella as the Center for Disease Control (CDC) does not recommend administering this vaccine during pregnancy due to its nature as a live attenuated virus vaccine. However, concerns that the co-administration of rubella vaccine with other immunoglobins (i.e., Rhogam) could compromise vaccine efficacy has produced warnings that can delay the administration of rubella vaccination postpartum, leaving women susceptible to the disease in subsequent pregnancies. We aimed to address whether the co-administration of the measles, mumps, and rubella (MMR) vaccine and Rhogam decreased antibody responses compared to those receiving only MMR vaccination. This retrospective cohort study utilized clinical data from 78 subjects who received the MMR vaccine and Rhogam after delivery and 45 subjects who received the MMR vaccine alone. Maternal demographics, pregnancy complications and rubella status at the start of a subsequent pregnancy were recorded for analysis. Overall, the two cohorts had similar baseline characteristics; however, lower parity was noted in the participants that received both MMR vaccination and Rhogam. Making assessments based on maternal antibody IgG index for rubella during the next pregnancy, we observed that 88% of the Rhogam + MMR vaccine group had positive serology scores, which was not significantly different from the 80% rate in the MMR-vaccine-only cohort (p = 0.2). In conclusion, no differences were observed in rubella immunity status in subsequent pregnancies in those mothers given both the MMR vaccine and Rhogam concurrently. Given these findings, warnings against co-administration of vaccines in combination with Rhogam appear unwarranted.