METHODS
This was an observational retrospective study conducted at Vall d’Hebron
Barcelona Hospital Campus, Barcelona, Spain. This study was approved by
the Vall d’Hebron Barcelona Hospital Campus Ethics Committee
(PR[AMI]556/2021) on 5th November 2021. For the
study group, inclusion criteria were women (a) attending our site with
confirmed SARS-CoV-2 infection at any point during pregnancy and (b)
undergoing the first-trimester combined screening for PE. The
recruitment period for the SARS-CoV-2 group was from February 2020 to
September 2021. Our centre was a referral hospital for severe COVID-19
pneumonia, especially during pregnancy; therefore, cases were both
patients from our area and patients referred from all across Catalonia.
For the population group, data was obtained from general population
attending first-trimester screening for PE in 6 centres across Catalonia
(Vall d’Hebron Barcelona Hospital Campus, Hospital Universitari Germans
Trias i Pujol, Hospital Universitari de Tarragona Joan XXIII, Hospital
Universitari Mútua Terrassa, Consorci Sanitari de Terrassa, Hospital
Universitari de Girona Doctor Josep Trueta) between May 2019 and June
2021. A previous study assessing the screening performance of the
first-trimester screening for PE was approved (PR(AMI)147/2021), and,
therefore, data from general population was prospectively recorded.
SARS-CoV-2 infection was confirmed either by real-time polymerase chain
reaction (RT-PCR) or an antigen test. Several changes in screening
protocols have occurred during the study period, while scientific
evidence or assistance care needs were changing. Therefore, our study
population included both patients systematically screened at hospital
admission and patients screened because of symptomatology or close
contact. In the study group, severity of the symptoms was the criteria
used for classification: mild forms of COVID-19, including asymptomatic
and symptomatic women not requiring hospitalization, and severe forms of
COVID-19, including patients requiring hospitalization due to severe
pneumonia.
In Catalonia, the first-trimester screening for PE is routinely
performed during the first-trimester scan between 11+0 and 13+6 weeks of
gestation. Gestational age is confirmed by fetal crown-rump length
measurement during this scan11. Demographic
characteristics, obstetric history, maternal history and biophysical and
biochemical markers are documented in the clinical records. Biophysical
markers, including transabdominal mean uterine artery pulsatility index
(UtAPI) and mean arterial blood pressure (MAP), are assessed during the
first-trimester scan. Biochemical markers, including serum
pregnancy-associated plasma protein-A (PAPP-A) and placental growth
factor (PlGF), are measured at the routine first-trimester blood test
(from 8+0 to 13+6 weeks of gestation). Maternal serum PAPP-A and PlGF
levels were determined by the fully automated Elecsys assays for PAPP-A
and PlGF on an immunoassay platform (cobas e analysers; Roche®
Diagnostics, Rotkreuz, Switzerland). First-trimester risk for PE was
then calculated4. High risk for PE was defined as a
risk for early-onset PE ≥ 1/170. This cut-off value provides a 90.9%
detection rate for early-onset PE at a 12.7% false-positive
rate12.
All examiners were certified by the Fetal Medicine Foundation for PE
risk assessment and Doppler ultrasound assessment.