Samba II PCR testing for COVID-19 in an unselected cohort of pregnant women in the UK

Abstract OBJECTIVE: Asymptomatic carriage of COVID-19 in pregnant women has been reported and could lead to outbreaks in maternity units. We sought to ascertain the impact of rapid isothernal nucleic acid based testing for COVID-19 in an unselected cohort of pregnant women attending our maternity unit. We also assessed the correlation between community prevalence and asymptomatic carriage.DESIGN: Retrospective cohort analysis and literature reviewSETTING: Tertiary hospital in Cambridge, UKPOPULATION: Pregnant women (with gestation age between 12-42 weeks) admitted to a single maternity unit over a 4-week period (07/05/2020-06/06/2020) METHODS: Data were collected using computerised hospital records. Literature searches were performed across multiple repositories. COVID-19 prevalence was extracted from online repositories.RESULTS: NP and OP swabs were obtained from 457/465 women during the study period (98%). The median turnaround time for results was 5.3 hours (interquartile range (IQR) 2.6-8.9 hours). 92% of results were returned within 24 hours. In our cohort, only one woman tested positive, giving a screen positive rate of 0.22% (1/457; 95% confidence interval: 0.04-1.23%). One woman who tested negative developed a fever postnatally following discharge but was lost to follow-up. From our literature review, we did not find any correlation between asymptomatic carriage in pregnant women and the reported regional prevalence of COVID-19. CONCLUSIONS: Testing using the SAMBA-II machine was acceptable to the vast majority of pregnant women requiring admission and had a low turnaround time. Asymptomatic carriage is low, but not correlated to community prevalence rates. Screening pregnant women on admission will remain an important component in order to minimise nosocomial infection.