Abstract
Objective This study aimed to determine the rate of preterm birth (PTB) during hospitalization
among women diagnosed with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)
between 23 and 37 weeks of gestation and whether this rate differs by gestational
age at diagnosis of infection.
Study Design Retrospective, cross-sectional study of all women diagnosed with SARS-CoV-2 infection
between 23 and 37 weeks of gestation within a large integrated health system from
March 13 to April 24, 2020. Cases with severe fetal structural malformations detected
prior to infection were excluded. Women were stratified into two groups based on gestational
age at diagnosis: early preterm (230/7 to 336/7 weeks) versus late preterm (34 to 366/7 weeks). We compared the rate of PTB during hospitalization with infection between
the two groups. Statistical analysis included use of Wilcoxon rank sum and Fisher
exact tests, as well as a multivariable logistic regression. Statistical significance
was defined as a p-value <0.05.
Results Of the 65 patients included, 36 (53.7%) were diagnosed in the early preterm period
and 29 (46.3%) were diagnosed in the late preterm period. Baseline demographics were
similar between groups. The rate of PTB during hospitalization with infection was
significantly lower among women diagnosed in the early preterm period compared with
late preterm (7/36 [19.4%] vs. 18/29 [62%], p-value = 0.001). Of the 25 patients who delivered during hospitalization with infection,
the majority were indicated deliveries (64%, 16/25). There were no deliveries <33
weeks of gestation for worsening coronavirus disease 2019 and severity of disease
did not alter the likelihood of delivery during hospitalization with SARS-CoV-2 infection
(adjusted odds ratio [aOR]: 0.64; 95% confidence interval [CI]: 0.24–1.59). Increased
maternal age was associated with a lower likelihood of delivery during hospitalization
with SARS-CoV-2 infection (aOR: 0.77; 95% CI: 0.58–0.96), while later gestational
age at diagnosis of infection was associated with a higher likelihood of delivery
during hospitalization (aOR: 2.9; 95% CI: 1.67–8.09).
Conclusion The likelihood of PTB during hospitalization with SARS-CoV-2 infection is significantly
lower among women diagnosed in the early preterm period compared with late preterm.
Most women with SARS-CoV-2 infection in the early preterm period recovered and were
discharged home. The majority of PTB were indicated and not due to spontaneous preterm
labor.
Key Points
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Preterm delivery is less likely among women diagnosed in the early preterm compared
with late preterm.
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Most women infected in the early preterm period recovered and were discharged home
undelivered.
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The majority of preterm birth were indicated and not due to spontaneous preterm labor.
Keywords
SARS-CoV-2 - COVID-19 - coronavirus - pregnancy - preterm birth - prematurity
