Discussion
We here report a 1.1% SARS-CoV-2 prevalence under presumed asymptomatic
labouring and hospital admitted pregnant women, taken in a six weeks’
interval that includes the peak incidence in Amsterdam in the end of
March, beginning of April. These results are in contrast with other
studies where percentages of SARS-CoV-2 in asymptomatic pregnant women
were as high as 3-14% [3 4]. Knowing that SARS-CoV-2 PCR testing
will not have 100% specificity, there will be false positive test
results. Consequently, in our setting PCR helped to increase a pre-test
likelihood of not having COVID-19 of 98.9% with an estimated 1
percentage point or less. It is therefore debatable which prevalence
rates are high enough to justify a policy of universal PCR testing and
full COVID-19 precautions if a patient has not been tested negative for
SARS-CoV-2. Given the delay associated with personal protection
equipment (PPE) for health care workers, and the potential for foetal
damage in obstetric urgencies, these conflicting interests should be
weighed carefully. Moreover, most pregnant women will undergo
loco-regional anaesthesia rather than aerosolizing general anaesthesia.
This further inflates the number of patients that needs to be screened
to prevent viral transmission from a patient to a health care worker.
Each hospital should therefore weigh the pros and cons of universal
screening versus PPE in their own setting and background incidence, to
balance the risks for health care workers versus the additional
perinatal risk of alternative care processes for unscreened patients in
obstetric emergencies.