Did we observe changes in obstetric interventions in SARS-CoV-2 infected pregnant women at the beginning of COVID-pandemic in Belgium? Results of a nationwide population-based study.

Background: Pregnant women are more vulnerable to the severe effects of COVID-19 compared to their non-pregnant peers. Early in the pandemic, there was a rise in cesarean deliveries and preterm births among infected pregnant women. This study aims to evaluate whether there were any changes in obstetric interventions during the first two waves of the pandemic in Belgium. Methods: Between March 2020 and February 2021, the Belgian Obstetric Surveillance System (B.OSS) conducted an extensive, nationwide population-based registry study, that included nearly all births to women with a confirmed SARS-CoV-2 infection within six weeks before hospitalization in Belgium. The perinatal outcomes of these women were analyzed and compared with pre-pandemic regional perinatal data. Results: A total of 923 SARS-CoV-2 infected pregnant women were admitted to the hospital; 9.3 % were hospitalized for severe COVID-19, while the remaining were hospitalized for obstetric reasons. Infected women had a higher median BMI, a higher incidence of diabetes, and a greater proportion were overweight or obese compared to the reference group (p < 0.001). While the majority of women gave birth vaginally, symptomatic women and those with a severe infection had slightly higher rates of cesarean delivery, though not statistically significant after adjusting for confounders. Only severely ill women had an increased risk of preterm delivery (aOR 2.3; 95 %CI [1.2-2.5]; p = 0.02) and of induced labor (OR 1.8; 95 %CI [1.1-2.8]; p = 0.01). The use of general anesthesia for cesarean delivery was more common in the infected group (OR 2.6; 95 %CI [1.6-4.1]; p < 0.001). Conclusions: Obstetric interventions, such as cesarean delivery and induction, remained at pre-pandemic levels. However, a SARS-CoV-2 infection appears to have increased medically induced preterm delivery and the use of general anesthesia for cesarean delivery.

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.

Late miscarriage and stillbirth in asymptomatic and symptomatic hospitalised pregnant women in Belgium during the first and second waves of COVID-19: a prospective nationwide population-based study.

BACKGROUND: Stillbirth has been recognized as a possible complication of a SARS-CoV-2 infection during pregnancy, probably due to destructive placental lesions (SARS-CoV-2 placentitis). The aim of this work is to analyse stillbirth and late miscarriage cases in unvaccinated pregnant women infected with SARS-CoV-2 during the first two waves (wild-type period) in Belgium. METHODS: Stillbirths and late miscarriages in our prospective observational nationwide registry of SARS-CoV-2 infected pregnant women (n = 982) were classified by three authors using a modified WHO-UMC classification system for standardized case causality assessment. RESULTS: Our cohort included 982 hospitalised pregnant women infected with SARS-CoV-2, with 23 fetal demises (10 late miscarriages from 12 to 22 weeks of gestational age and 13 stillbirths). The stillbirth rate was 9.5‰ for singleton pregnancies and 83.3‰ for multiple pregnancies, which seems higher than for the background population (respectively 5.6‰ and 13.8‰). The agreement between assessors about the causal relationship with SARS-Cov-2 infection was fair (global weighted kappa value of 0.66). Among these demises, 17.4% (4/23) were "certainly" attributable to SARS-CoV-2 infection, 13.0% (3/23) "probably" and 30.4% (7/23) "possibly". Better agreement in the rating was noticed when pathological examination of the placenta and identification of the virus were available, underlining the importance of a thorough investigation in case of intra-uterine fetal demise. CONCLUSIONS: SARS-CoV-2 causality assessment of late miscarriage and stillbirth cases in our Belgian nationwide case series has shown that half of the fetal losses could be attributable to SARS-CoV-2. We must consider in future epidemic emergencies to rigorously investigate cases of intra-uterine fetal demise and to store placental tissue and other material for future analyses.