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. 2018 Feb 1;2018(2):CD001269. doi: 10.1002/14651858.CD001269.pub6

pcb Dodds 2012.

Methods Retrospective cohort study
Participants Women who delivered a live or stillborn baby (> 500 g, singleton, > 20 weeks' gestation) at the IWK Clinical Centre (Halifax, Nova Scotia) between 1 April 2006 and 31 October 2009. In all, 9781 were included.
Interventions TIV seasonal vaccine (not otherwise specified). Women delivering at the IWK were asked whether or not they had received the influenza vaccine. This information was then further verified by using a specific database. Out of the 9781 included participants, 1957 received the vaccine.
Outcomes The information collected on influenza vaccination was linked to data from the Nova Scotia Atlee Perinatal Database (NSAPD, a population‐based database containing detailed clinical and demographic information for all deliveries in the province) to determine the characteristics of the cohort and the neonatal outcomes. The database includes live births and stillbirths born at a gestational age of at least 20 weeks or having a birth weight of at least 500 g, as well as extensive data on demographics, behaviour and lifestyle, labour and birth, and maternal and neonatal diseases and procedures. The following outcomes were considered:

  • Small for gestational age (≤ 10th percentile)

  • Low birth weight (≤ 2500 g)

  • Term low birth weight

  • Preterm birth (< 37 weeks)


Composite outcome
Notes Funding source ‐ government
This study was funded by grants from the IWK Health Centre and from the Atlee Foundation of the Department of Obstetrics and Gynecology, Dalhousie University.
Data were provided pooled for all 3 seasons and cover the entire years. Data for the time between 1 April 2007 and 31 December 2007 were missed.
Risk of bias
Bias Authors' judgement Support for judgement
PCS/RCS ‐ selection exposed cohort 
 All outcomes Low risk About half of deliveries in the region occur in the study health centre.
PCS/RCS ‐ selection non‐exposed cohort 
 All outcomes Low risk From the same source as exposed
PCS/RCS ‐ comparability 
 All outcomes Unclear risk It seems that not all possible confounding factors have been taken into account for calculation of adjusted estimate (only smoking habits Y/N). Only those modifying point estimate by > 5% were included.
PCS/RCS ‐ assessment of outcome 
 All outcomes Low risk Medical database records
Summary assessment Unclear risk Unclear risk of bias