ArticleBMC infectious diseases2018
Risk of pregnancy complications and adverse birth outcomes after maternal A(H1N1)pdm09 influenza: a Norwegian population-based cohort study.
Article in BMC infectious diseases, 2018. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT05321433 (The Association Between Tobacco Use and COVID-19 Infection and Adverse Outcomes in Three Nordic Countries), which is not on this map. Cited by 12 papers, 2 of them syntheses that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
The Association Between Tobacco Use and COVID-19 Infection and Adverse Outcomes in Three Nordic Countries: a Pooled Analysis
Who cites it
12 citing papers in PubMed, 2 syntheses or guidelines pooled it.
- SARS-CoV-2 infection during pregnancy and risk of preeclampsia: a systematic review and meta-analysis.American journal of obstetrics and gynecology · 2022Pooled it
- Effects of COVID-19 Infection during Pregnancy and Neonatal Prognosis: What Is the Evidence?International journal of environmental research and public health · 2020Pooled it
- Efficacy, duration of protection, birth outcomes, and infant growth associated with influenza vaccination in pregnancy: a pooled analysis of three randomised controlled trials.The Lancet. Respiratory medicine · 2020Trial
- Longitudinal study of genome-wide DNA methylation in individuals with and without post-acute symptoms following SARS-CoV-2 infection.Epigenomics · 2026Article
- Mechanistic insights into the impact of prenatal viral infections on maternal and offspring immunity.Npj viruses · 2026Review
- Influenza Activity and Preterm Birth in the Atlanta Metropolitan Area: A Time-Series Analysis from 2010 to 2017.Epidemiology (Cambridge, Mass.) · 2025Article
- Current tobacco use and SARS-CoV-2 infection in two Norwegian population-based cohorts.BMC public health · 2023Article
- Article
- Serological Responses to Influenza Vaccination during Pregnancy.Microorganisms · 2021Review
- Lessons learned from the A (H1N1) influenza pandemic.Best practice & research. Clinical obstetrics & gynaecology · 2021Review
- Incidence, risk factors and impact of seasonal influenza in pregnancy: A national cohort study.PloS one · 2021Article
- Detection of anti-NS1 antibodies after pandemic influenza exposure: Evaluation of a serological method for distinguishing H1N1pdm09 infected from vaccinated cases.Influenza and other respiratory viruses · 2020Article
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
8 authors.
Funding
Abstract
backgroundThe effects of maternal influenza infection on the fetus remain unclear. We studied mild influenza and influenza antibodies in relation to birth weight and risks of pre-eclampsia, preterm birth (PTB), and small for gestational age (SGA) birth among the unvaccinated participants in the Norwegian Influenza Pregnancy Cohort.
methodsPregnant women attending a routine ultrasound were recruited from four hospitals in Norway shortly after the 2009 A(H1N1) pandemic. The present study was restricted to unvaccinated participants who were pregnant during the pandemic. Information on the participants was obtained through questionnaires and linkage with national registries. Maternal blood samples were collected at delivery. Women with laboratory-confirmed A(H1N1)pdm09 influenza, a clinical diagnosis of influenza, or self-reported influenza during the pandemic were classified as having had influenza. A(H1N1)pdm09-specific antibodies in serum were detected with the hemagglutination-inhibition assay. Detection of antibodies was considered an indicator of infection during the pandemic in the unvaccinated participants. Odds ratios were estimated with logistic regression. Quantile regression was used to estimate differences in the distribution of birth weight.
resultsAmong the 1258 women included in this study, there were 37 cases of pre-eclampsia, 41 births were PTB, and 103 births were SGA. 226 women (18.0%) had influenza during the pandemic. The majority of cases did not receive medical care, and only a small proportion (1.3%) of the cases were hospitalized. Thus, the cases consisted primarily of women with mild illness. No significant associations between influenza and risk of pre-eclampsia, PTB, or SGA birth were observed. Detection of A(H1N1)pdm09-specific antibodies was associated with a lower 10th percentile of birth weight, β = - 159 g (95% CI - 309, - 9).
conclusionsMild influenza illness during pregnancy was not associated with increased risk of pre-eclampsia, PTB or SGA birth. However, influenza infection during pregnancy may reduce the birth weight of the smallest children.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.