The following is a summary of “Systematic review and synthesis of stillbirths and late miscarriages following SARS-CoV-2 infections,” published in the AUGUST 2023 issue of Obstetrics and Gynecology by Alcover, et al.
For a study, researchers sought to characterize fetal demise following SARS-CoV-2 infections and determine whether it was linked to clinical severity, placental lesions, malformations, or actual fetal infections.
A systematic search was conducted in PubMed and Web of Science databases from December 1, 2019, to April 30, 2022. The study included cohort, cross-sectional, case-control studies, case series, or case reports that described stillbirths or late miscarriages (occurring between 14 and 22 weeks of gestation) from pregnant mothers with SARS-CoV-2 infection. The infection was confirmed by a positive real-time reverse transcription-polymerase chain reaction from nasopharyngeal swabs and/or SARS-CoV-2 placental infection. Cases with other potential causes of fetal demise were excluded. The study adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and meta-analyses of Observational Studies in Epidemiology guidelines. The quality of case series and case reports was assessed using the Mayo Clinic Evidence-Based Practice Center tool. Data on maternal and fetal characteristics, placental histology, and virology findings were collected. Descriptive statistics were employed, and disease severity and fetal-neonatal infections were classified according to World Health Organization criteria.
The analysis encompassed data from 184 mothers and 190 fetuses. No discernible association with maternal clinical severity or fetal malformations was identified. Around 78% of fetal demise cases occurred in the second and third trimesters, approximately 6 to 13 days following SARS-CoV-2 diagnosis or symptom onset. Most placentas (88%) tested positive for SARS-CoV-2 or exhibited histologic features indicative of placentitis, akin to patterns seen in transplacentally transmitted infections (85%–91%). Remarkably, 11 fetuses (5.8%) had confirmed in-utero transmitted SARS-CoV-2 infections, while 114 fetuses (60%) had possible in-utero transmitted SARS-CoV-2 infections.
The study’s synthesis of available data suggested that fetal demise typically occurred shortly after SARS-CoV-2 infection, accompanied by histologic placental inflammatory lesions linked to transplacental SARS-CoV-2 transmission, which may lead to placental insufficiency.