Methods
The ItOSS launched a national population-based cohort study to collect
information on all women with a confirmed COVID-19 infection receiving
in or outpatient hospital care during pregnancy. A case is defined as a
pregnant woman with COVID-19 infection confirmed by reverse
transcriptase-polymerase chain reaction (RT-PCR) testing for the
SARS-CoV-2 virus, through a nasopharyngeal swab, and/or chest X-ray (RX)
or computed tomography (CT) findings, and/or through antibody response
from maternal peripheral blood.
The ItOSS relies on a network of trained reference clinicians, covering
91% of the nation’s live births (10). The network was extended to a
further seven Regions and two autonomous Provinces to reach nationwide
coverage for the present study.
The study core outcomes include COVID-19 pneumonia, invasive respiratory
support, ICU admission, women’s severe morbidity and mortality.
A multidisciplinary expert group — including obstetricians and
gynaecologists, maternal-foetal medicine specialists, neonatologists,
paediatricians, anaesthesiologists, midwives, and infectious disease
specialists — revised the data entry form and pre-tested its online
version.
The data entry form includes fields relating to women’s
socio-demographic characteristics, general and obstetric history,
COVID-19 infection diagnosis, treatment and complications. A follow-up
analysis will collect information on pregnancy outcomes, mode of
delivery and maternal and neonatal outcomes.
The clinicians working in the network maternity units use a secure
web-based data collection system to record incident cases. They received
a manual for the use of the web-based system and have constant help-desk
support.
On enrolment, women receive an informative note describing the study and
informed consent to the participation is acquired. The ItOSS sends a
weekly email to the contact clinicians of the health care facilities,
reminding them to report the new cases. For each notified case, a link
is sent for online data entry and a unique identifier code is generated.
Assuming that data relating to the reported cases might be missing, a
new request will be sent by email and, if further reminders are needed,
the contact person will be reached by phone.
In case of maternal death from SARS-CoV-2 infection, the ItOSS maternal
mortality surveillance system will allow verification and provide
further information. The data are collected and processed by personnel
in charge of ensuring confidentiality and security.
Since this is an observational study, the cohort size depends on the
incidence of the disease.
The preliminary data analysis focused on descriptive statistics
stratified by COVID-19 pneumonia occurrence. Significant differences
between the two groups were assessed through the Fisher’s exact test
suitable for the analysis of small samples.
All the analyses were performed using the Statistical Package Stata/MP
14.2.
This study has not received any funding and was conducted without
patient involvement due to lack of time and funds.