ArticleBMJ open2022
Risk factors for severe disease and impact of severity on pregnant women with COVID-19: a case-control study based on data from a nationwide survey of maternity services in Japan.
Article in BMJ open, 2022. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 7 papers, 1 of them a synthesis that pooled it.
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Who cites it
7 citing papers in PubMed, 1 synthesis or guideline pooled it, 10 citations in OpenAlex.
- COVID-19 in pregnant women: a systematic review and meta-analysis on the risk and prevalence of pregnancy loss.Human reproduction update · 2024Pooled it
- Impact of the COVID-19 pandemic on the monthly proportion of male births and spontaneous fetal death rates in Japan: a descriptive epidemiological study using national vital statistics.BMC public health · 2025Article
- Impact of Omicron BA.5 infection on maternal and neonatal outcomes.Frontiers in cellular and infection microbiology · 2025Article
- Predicting Intensive Care Unit Admission in COVID-19-Infected Pregnant Women Using Machine Learning.Journal of clinical medicine · 2024Article
- Decline in and recovery of fertility rates after COVID-19-related state of emergency in Japan.BMJ open · 2024Article
- The COVID-19 pandemic affects pregnancy complications and delivery outcomes in Japan: a large-scale nationwide population-based longitudinal study.Scientific reports · 2023Article
- Observational
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Authors and funding
7 authors at 4 institutions in 1 country.
Funding
No grant is acknowledged in the PubMed record.
Abstract
objectiveTo identify independent risk factors for severe COVID-19 in pregnant women and to evaluate the impact of disease severity on preterm birth.
designA case-control study based on data from a nationwide questionnaire-based survey of maternity services in Japan.
settingA questionnaire was mailed to all 2135 delivery institutions in Japan between July and August 2021. A total of 1288 institutions responded (60% of all delivery institutions in Japan). 566 facilities reported having cared for pregnant women with COVID-19, and 722 facilities reported having had no such patients.
participantsOne thousand and forty-three hospitalised and non-hospitalised pregnant women diagnosed with COVID-19 between July 2020 and 30 June 2021. PRIMARY AND SECONDARY OUTCOME MEASURES: The primary outcome was progression to severe COVID-19. The secondary outcome was preterm birth due to COVID-19 infection.
results56 cases (5.4%) were severe, and 987 (94.6%) were non-severe. Multivariable logistic regression analysis showed that gestational age≥24 weeks (adjusted OR (aOR) 6.68, 95% CI 2.8 to 16.0) and maternal age≥32 years (aOR 2.40, 95% CI 1.3 to 4.3) were independently associated with severe cases. Using the Kaplan-Meier method, the probability of continued pregnancy at 14 days after diagnosis for severe cases was 0.57 between 24 and 31 weeks' gestation and 0.27 between 32 and 36 weeks' gestation. The probability for non-severe cases was 1.0 between 24 and 31 weeks' gestation and 0.8 between 32 and 36 weeks' gestation. Among the patients with COVID-19 in the preterm period, preterm birth due to infection was significantly more common in severe than non-severe cases (48% vs 6%, p< 0.0001).
conclusionsSevere COVID-19 in pregnant women was associated with gestational age≥24 weeks and maternal age≥32. The rate of preterm delivery due to the infection was significantly higher in severe COVID-19 cases.
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