Meta-analysis on COVID-19-pregnancy-related placental pathologies shows no specific pattern

Area of Science:

• Obstetrics and Gynecology
• Infectious Diseases
• Pathology

Background:

• Pregnancy with severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) infection can lead to pneumonia.
• Previous case reports suggested potential fibrin and lymphohistiocytic placental lesions in COVID-19 pregnancies.
• A comprehensive meta-analysis to confirm COVID-19-associated placental lesions was lacking.

Purpose of the Study:

• To determine if there are characteristic placental pathological changes associated with Coronavirus disease 2019 (COVID-19) pneumonia in pregnant women.
• To assess the incidence of vascular and inflammatory lesions in placentas from COVID-19 pregnancies.
• To evaluate the frequency of transplacental viral transmission in SARS-CoV-2 infected pregnancies.

Main Methods:

• A systematic literature search was conducted for publications reporting on pregnancies with SARS-CoV-2 infection and placental examination.
• Meta-analysis included 30 publications from 2019 to 2021, encompassing 1452 placenta cases.
• Data on placental lesions, viral transmission, and maternal-fetal outcomes were analyzed.

Main Results:

• The meta-analysis did not identify any specific placental pathological changes unique to COVID-19 pneumonia.
• The incidence of vascular and inflammatory placental lesions was comparable to that observed in non-COVID-19 pregnancies.
• Transplacental transmission of SARS-CoV-2 was found to be very rare.

Conclusions:

• There are no typical placental changes associated with COVID-19 pneumonia in pregnancy.
• Maternal-fetal hypoxia, secondary to pneumonia, appears to be the most significant prognostic factor.
• The findings suggest that placental pathology is not a primary indicator of COVID-19 severity in pregnancy.