Plasticity of natural killer cells in pregnant patients infected with SARS-CoV-2 and their neonates during childbirth.

The COVID-19 pandemic has occurred due to infection caused by the SARS-CoV-2 coronavirus, which impacts gestation and pregnancy. In SARS-CoV-2 infection, only very rare cases of vertical transmission have been reported, suggesting that fetal immune imprinting due to a maternal infection is probably a result of changes in maternal immunity. Natural killer (NK) cells are the leading maternal immune cells that act as a natural defense system to fight infections. They also play a pivotal role in the establishment and maintenance of pregnancy. While peripheral NK cells display specific features in patients infected with SARS-CoV-2 in the general population, information remains elusive in pregnant mothers and neonates. In the present study, we analyzed the characteristics of NK cells isolated from both neonatal umbilical cord blood and maternal peripheral blood close to the time of delivery. Phenotype and functions were compared in 18 healthy pregnant women and 34 COVID-19 patients during pregnancy within an ongoing infection (PCR+; N = 15) or after recovery (IgG+PCR-; N = 19). The frequency of NK cells from infected women and their neonates was correlated with the production of inflammatory cytokines in the serum. The expression of NKG2A and NKp30, as well as degranulation of NK cells in pregnant women with ongoing infection, were both negatively correlated to estradiol level. Furthermore, NK cells from the neonates born to infected women were significantly decreased and also correlated to estradiol level. This study highlights the relationship between NK cells, inflammation, and estradiol in patients with ongoing infection, providing new insights into the impact of maternal SARS-CoV-2 infection on the neonate.

Impact of COVID-19 on Subclinical Placental Thrombosis and Maternal Thrombotic Factors.

BACKGROUND: In the context of the SARS-CoV-2 pandemic, our interest was to evaluate the effect of COVID-19 during pregnancy on placenta and coagulation factors. METHODS: a prospective cohort study between January and July 2021 of 55 pregnant women stratified into: Group O, 16 patients with ongoing SARS-CoV-2 infection at delivery; Group R, 21 patients with a history of SARS-CoV-2 infection during pregnancy but who recovered prior to delivery; Group C, 18 control patients with no infection at any time. All women had nasopharyngeal SARS-CoV-2 RT-PCR tests performed within 72 h of delivery. Obstetrical complications were recorded and two physiological inhibitors of coagulation, protein Z (PZ) and dependent protease inhibitor (ZPI), were analyzed in maternal and cord blood. All placentae were analyzed by a pathologist for vascular malperfusion. RESULTS: No patient in any group had a severe COVID-19 infection. More obstetrical complications were observed in Group O (O: n = 6/16 (37%), R: n = 2/21 (10%), C: n = 1/18 (6%), p = 0.03). The incidence of placental vascular malperfusion was similar among the groups (O: n = 9/16 (56%), R: n = 8/21 (42%), C: n = 8/18 (44%), p = 0.68). No PZ or ZPI deficiency was associated with COVID-19. However, an increased ZPI/PZ ratio was observed in neonates of Group R (O: 82.6 (min 41.3-max 743.6), R: 120.7 (29.8-203.5), C: 66.8 (28.2-2043.5), p = 0.04). CONCLUSION: COVID-19 was associated with more obstetrical complications, but not an increased incidence of placental lesions or PZ and ZPI abnormalities.

Impact of COVID-19 infection in pregnancy and neonates: A case control study.

OBJECTIVE: To evaluate maternal and neonatal outcomes of pregnant women who were infected by COVID-19 during pregnancy. STUDY DESIGN: A Case control retrospective study was conducted in an Obstetrical Department of a west Parisian area during the first year of COVID-19 pandemic. Maternal and neonatal outcomes were compared between a group of women infected by the SARS-CoV-2 virus during pregnancy (March 2020- February 2021) and a control group of women delivering before pandemic. They were matched according to age and parity. Subgroups of SARS-CoV-2 infection occurring before vs after 37 weeks of gestations and symptomatic vs asymptomatic patients were analyzed. The rate of preterm birth, preeclampsia, placental abruption and stillbirth were compared between the year of pandemic and the year before for all deliveries. RESULTS: Maternal and neonatal outcomes were similar. Among the 86 pregnant women with SARS-CoV-2 infection, five were admitted to Hospital (5.8%). One was transferred in intensive care unit for respiratory distress (1.2%). All patients had favorable outcomes. Patients with symptoms had more associated comorbidities (34.5%, n = 20/58, with symptoms, vs 9,1%, n = 2/22, without symptoms, p = 0.023). No differences in preeclampsia, placenta abruption and stillbirth, but less preterm births (4.9%, n = 160/3383 vs 6.2%, n = 209/3235, p = 0.04) were observed between the year of pandemic and the year before. CONCLUSION: There were few complications associated with COVID-19 infection among pregnant patients and their neonates. A low rate of associated comorbidities, a good access to healthcare services in this area and the small sample size of patients could explain these results.