Preterm birth is not associated with asymptomatic/mild SARS-CoV-2 infection per se: Pre-pregnancy state is what matters.

Abstract

Evidence for the real impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on preterm birth is unclear, as available series report composite pregnancy outcomes and/or do not stratify patients according to disease severity. The purpose of the research was to determine the real impact of asymptomatic/mild SARS-CoV-2 infection on preterm birth not due to maternal respiratory failure. This case-control study involved women admitted to Sant Anna Hospital, Turin, for delivery between 20 September 2020 and 9 January 2021. The cumulative incidence of Coronavirus disease-19 was compared between preterm birth (case group, n = 102) and full-term delivery (control group, n = 127). Only women with spontaneous or medically-indicated preterm birth because of placental vascular malperfusion (pregnancy-related hypertension and its complications) were included. Current or past SARS-CoV-2 infection was determined by nasopharyngeal swab testing and detection of IgM/IgG antibodies in blood samples. A significant difference in the cumulative incidence of Coronavirus disease-19 between the case (21/102, 20.5%) and the control group (32/127, 25.1%) (P= 0.50) was not observed, although the case group was burdened by a higher prevalence of three known risk factors (body mass index > 24.9, asthma, chronic hypertension) for severe Coronavirus disease-19. Logistic regression analysis showed that asymptomatic/mild SARS-CoV-2 infection was not an independent predictor of spontaneous and medically-indicated preterm birth due to pregnancy-related hypertension and its complications (0.77; 95% confidence interval, 0.41-1.43). Pregnant patients without comorbidities need to be reassured that asymptomatic/mild SARS-CoV-2 infection does not increase the risk of preterm delivery. Preterm birth and severe Coronavirus disease-19 share common risk factors (i.e., body mass index > 24.9, asthma, chronic hypertension), which may explain the high rate of indicated preterm birth due to maternal conditions reported in the literature.

• Authors: Stefano Cosma, Andrea Roberto Carosso, Jessica Cusato, Fulvio Borella, Marco Carosso, Fiammetta Gervasoni, Ilaria Stura, Mario Preti, Valeria Ghisetti, Giovanni Di Perri, Chiara Benedetto
• Journal: PloS one (PLoS One) Vol. 16 Issue 8 Pg. e0254875 ( 2021) ISSN: 1932-6203 [Electronic] United States
• PMID: 34351922 (Publication Type: Journal Article)

Topics

• Abortion, Spontaneous
• Adult
• COVID-19 (transmission)
• Carrier State (immunology, virology)
• Case-Control Studies
• Female
• Hospitalization
• Humans
• Infant, Newborn
• Infectious Disease Transmission, Vertical (statistics & numerical data)
• Placenta (physiopathology)
• Pre-Eclampsia
• Pregnancy
• Pregnancy Complications, Infectious (epidemiology)
• Pregnancy Outcome (epidemiology)
• Premature Birth (epidemiology, immunology, virology)
• Risk Factors
• SARS-CoV-2 (pathogenicity)