1. To investigate maternal outcomes in women infected with the 2009 H1N1 Influenza A virus
2. To investigate the perinatal outcomes in babies of women infected with the 2009 H1N1 influenza A virus
The following databases will be searched:
MEDLINE Medline (1966- present), Excerpta Medica Database (EMBASE Embase) (1974 to present), Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects (DARE), and Web of Science
The bibliographies of included articles, previously published systematic reviews and review articles will be searched for additional sources.
Inclusion criteria: Prospective and retrospective cohort studies.
Exclusion: Case reports and case series.
Condition or domain being studied
2009 H1N1 pandemic influenza in pregnancy.
Inclusion criteria: pregnant or postpartum women infected with the H1N1 (influenza A) virus during the 2009 pandemic.
Exclusion criteria: neonates, infants, children, non -pregnant adults, influenza virus other than the 2009 H1N1 (Influenza A) virus pandemic.
Exposures: 2009 H1N1 (Influenza A) virus and pregnancy.
If available, pregnant or postpartum women not infected with 2009 H1N1 influenza.
Early neonatal death
Late neonatal death
Termination of pregnancy
Neonatal H1N1 infection
Major congenital anomaly
Small for gestational age
Maternal intensive care unit admission
Maternal intubation and mechanical ventilation
Severe maternal morbidity (secondary pneumonia, neurological deficit)
Duration of hospitalization (maternal and neonatal)
Caesarean section delivery
Neonatal intensive care unit admission
Data extraction, (selection and coding)
Following the initial search (with duplicates removed), the abstracts of selected articles will be reviewed to determine whether full text review is required. Studies will be excluded based on the criteria set above.
We will proceed to full text review if: 1) the abstract is unavailable; 2) the abstract has insuffient information; 3) the study appears to meet eligibility. Assessment for full text review will be undertaken by a single reviewer (TF); any studies where there is uncertainty about eligibility will be included in full text review.
At the full text review phase, studies will be examined independently by two reviewers (TF, MK) to assess whether they meet the inclusion criteria.
Data will be extracted using a standard data collection sheet. Data will be abstracted independently by two reviewers (TF and MK) and discrepancies will be resolved by discussion.
Data fields to be abstracted:
1) Country of study
a. hospital, clinic or community
b. if hospital, location where study is carried out: intensive care unit or ward
4) Population (pregnant and/or postpartum women)
5) Controls (if available)
6) Number of women in exposed and unxposed groups
7) Study design
1) Mean maternal age
3) Pre-existing health conditions
a) asthma and/or other respiratory conditions
1) Maternal immunization against H1N1
2) Received neuraminidase inhibitors
3) Timing of treatment
1) Maternal mortality
2) Maternal intensive care unit admission
3) Maternal intubation and mechanical ventilation
4) Severe Maternal Morbidity
5) Duration of hospitalization
1) Early neonatal death
2) Late neonatal death
4) Spontaneous abortion
5) Termination of pregnancy
6) Mode of delivery
7) Gestational age at delivery
8) Major congenital anomaly
9) Small for gestational age
10) Neonatal intensive care unit admission
11) Duration of hospitalization
Risk of bias (quality) assessment
Risk of bias will be assessed for each included study.
We will use two applicable components of the Cochrane Risk of Bias tool: Selective Outcome Reporting and Incomplete Outcome Data.
The quality of each trial will be evaluated independently by two reviewers (TF and MK).
Strategy for data synthesis
All studies will be included in a descriptive analysis.
A quantitative analysis of each outcome will be undertaken; the summary statistic used will be odds ratio (and 95% confidence interval, CI) using a random effects model. We will present a forest plot for each outcome if possible. Heterogeneity will be assessed by the I-squared statistic. If I-squared >50% (significant heterogeneity), we will examine differences in study quality, design and outcome defintions to investigate the cause of the heterogeneity.
Cochrane Review Manager 5.1 will be used for statistical analysis.
The review will comply with the MOOSE reporting guidelines for meta-analysis of observational studies in epidemiology.
Analysis of subgroups or subsets
If sufficient data are obtained (two studies or more) for postpartum women, we will perform a subgroup analysis of outcomes in postpartum women (compared to that of pregnant women).
If sufficient data are obtained (two or more studies) for low and middle income countries (as defined by the World Bank), we will perform a subgroup analysis of outcomes in women in low middle income countries (compared to that of women in high income countries).
The review is planned to be published in a peer-reviewed journal.
Contact details for further information
Room F2- 4500 Oak Street
Women's and Children's Hospital of British Columbia
Vancouver, BC V6H 3N1
Organisational affiliation of the review
University of Bristish Columbia
Dr Tabassum Firoz, University of British Columbia Professor Marian Knight, National Perinatal Epidemiology Network, University of Oxford
Details of any existing review of the same topic by the same authors
Anticipated or actual start date
25 May 2012
Anticipated completion date
30 September 2012
Dr. Firoz is supported by the Univeristy of British Columbia Clinician Investigator Program
Formal screening of search results against eligibility criteria
Risk of bias (quality) assessment
PROSPERO This information has been provided by the named contact for this review. CRD has accepted this information in good faith and registered the review in PROSPERO. CRD bears no responsibility or liability for the content of this registration record, any associated files or external websites.