key: cord-0972954-g1t6md86
authors: Boujenah, Jeremy
title: Preeclampsiada risk factor to get infected with COVID-19 or a selection bias?
date: 2021-09-02
journal: Am J Obstet Gynecol
DOI: 10.1016/j.ajog.2021.08.042
sha: 344ef686a809f3725939ec2cdb35e7935d2a07c4
doc_id: 972954
cord_uid: g1t6md86

nan

Preeclampsiada risk factor to get infected with COVID-19 or a selection bias?

TO THE EDITORS: In the recent report of the INTER-COVID study-a prospective international study-the authors observed an association between COVID-19 and preeclampsia. 1 The hypothesis formulated for the observed association was that preeclampsia is a vascular condition that precedes infection by SARS-CoV-2, and it increases the risk of COVID-19. This underlying pathway is unclear and could reflect selection bias. Considering this issue, the selection of women might overestimate the association. Firstly, the controls should be identified as cases if they have developed the disease, and the probability of developing the disease should be consistent in both the groups. However, 50% of nondiagnosed COVID-19 cases had not been tested, and serology to exclude previous COVID-19 infection was performed only in 32 (2.2%) women. Secondly, the reason for testing women, especially those who were asymptomatic, could vary depending on whether preeclampsia is present or not (ie, independence on the outcome of preeclampsia is not consistent across exposure to COVID-19). This point raises the possibility of Berkson bias. Thirdly, the authors did not discuss that a vaccine campaign could have affected the number of cases. Fourthly, because of the progressive implementation of adequate polymerase chain reaction (PCR) testing and the prolonged shedding of RNA in respiratory samples, the result of the PCR test across 18 countries could have resulted in a bias in the diagnosis of cases. Adjustment on the site or bivariate analysis according to the cycle threshold value of quantitative reverse transcriptase PCR could be interesting.

It has been observed in adults that hypertension could be a sequela in patients with SARS-COV-2 infection. 2 In contrast, no association was found between the delay of COVID-19 infection and birth if >7 days. Women with vascular conditions or severe COVID-19 are at a greater risk of getting seriously ill rather than being positive on an PCR test. 3 The delay between a positive COVID-19 test and the occurrence of preeclampsia could help to overcome these assumptions. 4 

Preeclampsia and COVID-19: results from the INTERCOVID prospective longitudinal study

Hypertension as a sequela in patients of SARS-CoV-2 infection

Epidemiology of coronavirus disease 2019 in pregnancy: risk factors and associations with adverse maternal and neonatal outcomes

Coronavirus disease 2019 infection and hypertensive disorders of pregnancy

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The author reports no conflict of interest.The author reports no funding sources.