Study Methods

Information regarding the All Our Families cohort, including study design, is available below.


The All Our Families cohort began in 2008 with the recruitment of 3,200 Alberta mother-baby pairs. Mothers were recruited before they were 25-weeks of gestation and were eligible if they were undergoing prenatal care for a singleton pregnancy in Calgary, Alberta, Canada.

Since those first surveys, the All Our Families has continued to receive funding to follow these mother-baby pairs for nearly two decades.


How to Develop an AOF Questionnaire


Data Collection Snapshot


Study Timeline


The All Our Babies pregnancy cohort: design, methods, and participant characteristics.

The prospective cohort study design is ideal for examining diseases of public health importance, as its inherent temporal nature renders it advantageous for studying early life influences on health outcomes and research questions of aetiological significance. This paper will describe the development and characteristics of the All Our Babies (AOB) study, a prospective pregnancy cohort in Calgary, Alberta, Canada designed to examine determinants of maternal, infant, and child outcomes, and identify barriers and facilitators in health care utilization.

Women were recruited from health care offices, communities, and through Calgary Laboratory Services before 25 weeks gestation from May 2008 to December 2010. Participants completed two questionnaires during pregnancy, a third at 4 months postpartum, and are currently being followed-up with questionnaires at 12, 24, and 36 months. Data was collected on pregnancy history, demographics, lifestyle, health care utilization, physical and mental health, parenting, and child developmental outcomes and milestones. In addition, biological/serological and genetic markers can be extracted from collected maternal and cord blood samples.

Paper Link (McDonald et al., 2013)

All Our Babies cohort study: predict women at risk of preterm birth through gene expression profiles and environment

The All Our Babies Study is an on-going community based longitudinal cohort study that was designed to establish a cohort of women to investigate how a women's genetics and environment contribute to the pathophysiology of preterm birth. Specifically this study will examine the predictive potential of maternal leukocytes for predicting preterm birth in non-labouring women through the examination of gene expression profiles and gene-environment interactions.

Collaborations have been established between clinical lab services, the provincial health service provider and researchers to create an interdisciplinary study design for the All Our Babies Study. A birth cohort of 2000 women has been established to address this research question. Women provide informed consent for blood sample collection, linkage to medical records and complete questionnaires related to prenatal health, service utilization, social support, emotional and physical health, demographics, and breast and infant feeding. Maternal blood samples are collected in PAXgene™ RNA tubes between 18-22 and 28-32 weeks gestation for transcriptomic analyses.

Paper Link (Gracie et al., 2010)

Comparison of sample characteristics in two pregnancy cohorts: community-based versus population-based recruitment methods

One of the biggest challenges for population health studies is the recruitment of participants. Questions that investigators have asked are “who volunteers for studies?” and “does recruitment method influence characteristics of the samples?” The purpose of this paper was to compare sample characteristics of two unrelated pregnancy cohort studies taking place in the same city, in the same time period, that employed different recruitment strategies, as well as to compare the characteristics of both cohorts to provincial and national statistics derived from the Maternity Experiences Survey (MES).

One pregnancy cohort used community-based recruitment (e.g. posters, pamphlets, interviews with community media and face-to-face recruitment in maternity clinics); the second pregnancy cohort used both community-based and population-based (a centralized system identifying pregnant women undergoing routine laboratory testing) strategies.

Paper Link (Leung et al., 2013)

Reliability and validity of three shortened versions of the State Anxiety Inventory scale during the perinatal period

The screening for anxiety in obstetric settings has been challenging due to time and knowledge constraints. Brief, valid, and reliable instruments can provide health care professionals with a quick and easy method to assess anxiety. Three six-item forms of the State Anxiety Inventory scale have been constructed. The purpose of this study was to evaluate and compare the psychometric properties of these short versions in the perinatal period.

Data were drawn from a longitudinal pregnancy cohort in Alberta, Canada. Internal consistency of the shortened versions was assessed. Confirmatory factor analysis was conducted to estimate and compare indicators of fit during pregnancy and at 4 and 12 months postpartum.

Paper Link (Bayrampour et al., 2014)

Examining the psychometric properties of three standardized screening tools in a pregnant and parenting population

Although standardized tools such as the Speilberger State Anxiety scale (1970) and Cohen’s Perceived Stress Index (1983) have often been used in pregnant and postpartum populations to evaluate psychosocial risk, there exists very little literature on the reliability of these scales in this population. Given the potentially grave consequences of undiagnosed pre and postpartum mental distress, it is of paramount importance that the tools that are commonly used are evaluated for their psychometric properties within the pregnant and parenting population.

The psychometric properties of three mental health scales were evaluated using the All Our Babies data. Participants were mailed questionnaires at 24–26 weeks gestation, 34–36 weeks and at 4 months postpartum. Reliability for the Speilberger State Anxiety Scale, the Perceived Stress Index and the Life Optimism Test—revised were evaluated by calculating Cronbach’s alphas. Validity with related constructs were tested for the State Anxiety Scale and the Perceived Stress Index by calculating Pearson Correlation Coefficients with closely related constructs. Depression as a related construct was evaluated using the Edinburgh Postpartum Depression Scale.

Paper Link (Benediktsson et al., 2017)

Cohort profile: the All Our Babies pregnancy cohort (AOB)

All Our Babies (AOB) is a community-based, longitudinal pregnancy cohort developed to investigate the relationships between the prenatal and early life periods and outcomes for infants, children and mothers. The design of AOB follows a life course perspective, whereby the influence of early events on long-term health and development of both mothers and children are investigated through examining factors across life stages.

Mothers have completed questionnaires from pregnancy to 3 years postpartum, and consented to providing the research team with access to their obstetric medical records. Data collection for a 5-year follow-up questionnaire is ongoing. A subgroup within the cohort participated in the ‘prediction of preterm birth’ component and provided blood samples during pregnancy and an umbilical cord blood sample. The continuation of follow-up to 8 years is under way.

Paper Link (Tough et al., 2017)

Quality assessment of RNA in long-term storage: the All Our Families biorepository

The All Our Families (AOF) cohort study is a longitudinal population-based study which collected biological samples from 1948 pregnant women between May 2008 and December 2010. As the quality of samples can decline over time, the objective of the current study was to assess the association between storage time and RNA (ribonucleic acid) yield and purity, and confirm the quality of these samples after 7–10 years in long-term storage.

Maternal whole blood samples were previously collected by trained phlebotomists and stored in four separate PAXgene Blood RNA Tubes (PreAnalytiX) between 2008 and 2011. RNA was isolated in 2011 and 2018 using PAXgene Blood RNA Kits (PreAnalytiX) as per the manufacturer’s instruction. RNA purity (260/280), as well as RNA yield, were measured using a Nanodrop. The RNA integrity number (RIN) was also assessed from 5–25 and 111–130 months of storage using RNA 6000 Nano Kit and Agilent 2100 BioAnalyzer.

Paper Link (Stephenson et al., 2020)

Cross-sectional study protocol for the COVID-19 impact survey of mothers and their 7-11 year old children in Alberta, Canada

Our aim is to understand the effect of the COVID-19 pandemic on families who have been followed longitudinally in two cohorts studied in Alberta, Canada. We will examine household infections during the COVID-19 pandemic, financial impact, domestic violence, substance use, child school and daily life and relationships in the home. We will identify risk and protective factors for maternal mental health outcomes using longitudinal data that can inform policy and government resource allocation in future disasters. 

Mothers were invited to complete the baseline COVID-19 Impact Survey (20-30 min) within 4 months of March 15, 2020, which was when the province of Alberta, Canada, implemented school closures and physical-distancing measures to prevent the spread of COVID-19. Mothers were re-surveyed at 6 months after completion of the initial COVID-19 Impact Survey, and will be re-surveyed again at 12 months. Descriptive, multivariable analysis will be undertaken to examine risk and resiliency over time and factors that predict mental health and well-being.

Paper Link (Letourneau et al., 2021)