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.

Skin-to-skin transfer from the delivery room to the neonatal unit for neonates of 1,500g or above: a feasibility and safety study.

Objective: Immediate skin-to-skin contact (SSC) is already standard care for healthy term newborns, but its use for term or preterm newborns requiring admission to neonatal intensive care unit (NICU) with or without respiratory support is challenging. This study aimed to assess the safety and feasibility of SSC during the transfer of newborn infants, using a new purpose-built mobile shuttle care-station, called "Tandem". Material and methods: A monocentric prospective observational study was conducted at the tertiary referral center of the Université libre de Bruxelles in Brussels, Belgium after ethical approval by Hopital Erasme's Ethics Committee (ClinicalTrials.gov ID: NCT06198478). Infants born with a birth weight above 1,500 g were included. Following initial stabilization, infants were placed in SSC with one of their parents and transferred to the NICU using the Tandem. Results: Out of 65 infants initially included, 64 (98.5%) were successfully transported via SSC using the Tandem. One transfer was not successful due to last minute parental consent withdrawal. The median (range) duration of continuous skin-to-skin contact after birth was 120 min (10-360). SSC transfers were associated with gradually decreasing heart rate (HR) values, stable oxygen saturation levels (SpO2), and no increase in median fraction of inspired oxygen (FiO2). Heatloss was predominantly observed during initial setup of SSC. There was no significant difference in the occurrence of tachycardia, desaturation or hypothermia between preterm and term neonates. No equipment failures compromising the transfer were recorded. Conclusion: Skin-to-skin transfer of infants with a birthweight of equal or above 1,500 g using the Tandem shuttle is feasible and associated with stable physiological parameters. This method facilitates early bonding and satisfies parents. Clinical Trial Registration: ClinicalTrials.gov (NCT06198478).