Adverse Pregnancy Outcomes Among Individuals With and Without Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): A Systematic Review and Meta-analysis.

OBJECTIVE: To compare the risk of intrauterine fetal death (20 weeks of gestation or later) and neonatal death among individuals who tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) compared with those who tested negative for SARS-CoV-2 on admission for delivery. DATA SOURCES: MEDLINE, Ovid, EMBASE, Cumulative Index to Nursing and Allied Health, and Cochrane Library were searched from their inception until July 17, 2020. Hand search for additional articles continued through September 24, 2020. ClinicalTrials.gov was searched on October 21, 2020. METHODS OF STUDY SELECTION: The inclusion criteria were publications that compared at least 20 cases of both pregnant patients who tested positive for SARS-CoV-2 on admission to labor and delivery and those who tested negative. Exclusion criteria were publications with fewer than 20 individuals in either category or those lacking data on primary outcomes. A systematic search of the selected databases was performed, with co-primary outcomes being rates of intrauterine fetal death and neonatal death. Secondary outcomes included rates of maternal and neonatal adverse outcomes. TABULATION, INTEGRATION, AND RESULTS: Of the 941 articles and completed trials identified, six studies met criteria. Our analysis included 728 deliveries to patients who tested positive for SARS-CoV-2 and 3,836 contemporaneous deliveries to patients who tested negative. Intrauterine fetal death occurred in 8 of 728 (1.1%) patients who tested positive and 44 of 3,836 (1.1%) who tested negative (P=.60). Neonatal death occurred in 0 of 432 (0.0%) patients who tested positive and 5 of 2,400 (0.2%) who tested negative (P=.90). Preterm birth occurred in 95 of 714 (13.3%) patients who tested positive and 446 of 3,759 (11.9%) who tested negative (P=.31). Maternal death occurred in 3 of 559 (0.5%) patients who tested positive and 8 of 3,155 (0.3%) who tested negative (P=.23). CONCLUSION: The incidences of intrauterine fetal death and neonatal death were similar among individuals who tested positive compared with negative for SARS-CoV-2 when admitted to labor and delivery. Other immediate outcomes of the newborns were also similar among those born to individuals who tested positive compared with negative for SARS-CoV-2. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42020203475.

Progressive long-term spatial memory loss following repeat concussive and subconcussive brain injury in mice, associated with dorsal hippocampal neuron loss, microglial phenotype shift, and vascular abnormalities.

There is considerable concern about the long-term deleterious effects of repeat head trauma on cognition, but little is known about underlying mechanisms and pathology. To examine this, we delivered four air blasts to the left side of the mouse cranium, a week apart, with an intensity that causes deficits when delivered singly and considered "concussive," or an intensity that does not yield significant deficits when delivered singly and considered "subconcussive." Neither repeat concussive nor subconcussive blast produced spatial memory deficits at 4 months, but both yielded deficits at 14 months, and dorsal hippocampal neuron loss. Hierarchical cluster analysis of dorsal hippocampal microglia across the three groups based on morphology and expression of MHCII, CX3CR1, CD68 and IBA1 revealed five distinct phenotypes. Types 1A and 1B microglia were more common in sham mice, linked to better neuron survival and memory, and appeared mildly activated. By contrast, 2B and 2C microglia were more common in repeat concussive and subconcussive mice, linked to poorer neuron survival and memory, and characterized by low expression levels and attenuated processes, suggesting they were de-activated and dysfunctional. In addition, endothelial cells in repeat concussive mice exhibited reduced CD31 and eNOS expression, which was correlated with the prevalence of type 2B and 2C microglia. Our findings suggest that both repeat concussive and subconcussive head injury engender progressive pathogenic processes, possibly through sustained effects on microglia that over time lead to increased prevalence of dysfunctional microglia, adversely affecting neurons and blood vessels, and thereby driving neurodegeneration and memory decline.