Pharyngeal sampling for PCR-testing in the investigation of SARS-COV-2 vertical transmission in pregnancy

The novel COVID-19 global pandemic has raised, among many others, major concerns regarding the impact of infection during pregnancy. At the time of this writing, vertical SARS-COV-2 transmission in pregnancy has been considered probable, but is yet to be confirmed. According to the published reports of infants born to COVID-19-affected mothers, as well as the anecdotal experience of current practices worldwide, it appears that investigations regarding the possibility of SARS-COV-2 vertical transmission in pregnancy have so far been based, to a large extent, on PCR testing of neonatal pharyngeal swab samples. Given that the hypothetical route of vertical transmission for SARS-COV-2 is less likely to involve the upper respiratory tract, contrary to what happens after birth, it would be advisable to include appropriate biological samples, such as cord blood, placenta, amniotic fluid and neonatal blood, along with the pharyngeal samples, in order to contribute significantly to such investigations. Revision and enhancement of the so far prevailing practices appear even more important, as the impact of SARS-COV-2 infection occurring early in pregnancy is still unknown, this challenge remaining to be confronted in the immediate future.