Absence of SARS-CoV-2 in Second-Trimester Amniotic Fluid During the SARS-CoV-2 Virus Pandemic

To determine the presence or absence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in second-trimester amniotic fluid during the SARS-CoV-2 virus pandemic in patients undergoing genetic amniocentesis.

Women undergoing amniocentesis between September 2020 and April 2022 were asked to participate in the study. On the day of amniocentesis, an additional 5 mL of amniotic fluid, 5 mL of maternal blood sample, and nasal swabs were collected from each participant. None of the patients had active SARS-CoV-2 infection on the date of amniocentesis. Demographic data and history of SARS-CoV-2 virus infection were collected. After 2021, the SARS-CoV-2 virus vaccination status was obtained. Amniotic fluid and maternal nasal swabs were collected and tested for the presence of the SARS-CoV-2 virus via real-time reverse-transcriptase polymerase chain reaction test using an automated bead-based method for extracting total nucleic acid. An electrochemiluminescence immunoassay on maternal blood was used to detect SARS-CoV-2 total (immunoglobin G/immunoglobin M) antibodies against nucleocapsids.

This study enrolled 92 patients. There were 16 patients who reported a history of SARS-CoV-2 virus infection: 8 of them reported SARS-CoV-2 virus infection during the first and second trimesters and 8 reported SARS-CoV-2 virus infection before pregnancy. A total of 49 patients were vaccinated prior to amniocentesis. All 92 amniotic fluid samples tested negative for the SARS-CoV-2 virus. There were five positive and three negative SARS-CoV-2 maternal nucleocapsid antibody tests among the eight patients who had the SARS-COV-2 viral infection during the first and second trimesters of pregnancy. All eight patients had negative swab tests for the SARS-CoV-2 virus.

There was no SARS-CoV-2 virus in the second-trimester amniotic fluid samples from the eight patients who reported SARS-CoV-2 viral infection during the first and second trimesters. This finding suggests that, after a first- and second-trimester SARS-CoV-2 virus infection, it is unlikely to find the SARS-CoV-2 virus in the amniotic fluid.