Methodology

 

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Cohort profile: the All Our Babies cohort (AOB)

Suzanne Tough, Sheila McDonald, Beverly Collisson, Susan Graham, Heather Kehler, Dawn Kingston, Karen Benzies

 

Extract:  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.1 AOB spans pregnancy, birth and early postpartum through childhood, and therefore provides the unique opportunity to describe the relations between prenatal events and early life development and to examine key factors that influence child and mother well-being over time.

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AOB was originally designed to measure maternal and infant outcomes during the perinatal period, with a particular emphasis on barriers and facilitators to accessing health care services in Calgary,...

 

Examining the Psychometric Properties of Three Standardized Screening Tools in a Pregnant and Parenting Population

Ingunn Benediktsson, Sheila McDonald, Suzanne Tough

 

Significance: 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.

Methods: The psychometric properties of three mental health scales were evaluated using the All Our Babies data. The All Our Babies cohort is a prospective longitudinal study based in Calgary, Alberta. A total of 3300 women were recruited from prenatal care sites from all four quadrants of the city. 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. Sample size varied from 2670 to 3376, according to the response rate and time point. Depression as a related construct was evaluated using the Edinburgh Postpartum Depression Scale.

Results: The Cronbach’s Alphas for the Speilberger State Anxiety scale were 0.92, 0.92 and 0.93 for 24–26 weeks, 34–36 weeks and 4 months postpartum respectively. The Alpha’s for the Perceived Stress index were 0.88, 0.88 and 0.89 respectively. The Life Optimism Test Revised was only measured in the third trimester and the Cronbach’s alpha was 0.83. The Pearson Correlation Coefficient for Anxiety with depression were r = 0.73, r = 0.72 and r = 0.77 respectively. The coefficients for stress and depression were r = 0.75, r = 0.75 and r = 0.77 respectively.

Discussion/Conclusion: The psychometric properties for all three scales were strong, with alphas that were comparable or higher to literature values. These data provide evidence that the use of these scales, previously validated in other populations are appropriate for use in among pregnant and parenting women at risk for mental distress.

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

Hamideh Bayrampour, Sheila McDonald, Tak Fung and Suzanne Tough

 

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. All shortened scales demonstrated high internal consistency and reliability, with alphas ranging from 0.81 to 0.85. All fit indices were greater than 0.93, implying a good fit between each model and our data. In the model comparisons, the Marteau and Bekker scale provided a more robust fit to data obtained during pregnancy and the early postpartum period. At 12 months postpartum, the Chlan et al. form demonstrated the best fit of the three versions. The shortened scales appear to have acceptable psychometric properties. Brief scales have the potential to provide an economical means of assessing perinatal anxiety and can be considered as equivalent alternatives to the full-scale version.

 

Preterm Birth and Healthy Outcomes Team: the science and strategy of team-based investigation

Suzanne Tough

Introduction: In the traditional academic environment, there are often more reasons not to construct a team than there are reasons to construct one. In particular, there are institutional and funder guidelines for reward and recognition that are disincentives to the creation of a team. There are temporal pressures that favor small group work and incremental science over large groups and high risk projects. In addition, we are increasingly encouraged to make our research relevant and valid while reducing the time required for the translation of evidence to practice and policy. While the need for accurate science is paramount, these requests must still be accommodated within the parameters of academic and health delivery systems in flux, reductions in research budgets, and changing government priorities.

Nevertheless, an unparalleled opportunity is created when a group of dedicated people with the desire to address a common, complex problem realize that a solution cannot be reached within the traditional paradigm. These people recognize that the solutions do not lie within the realm of a single discipline, faculty, institution, theoretical framework, or dogma, and they are willing to look for new ways of working together. Such is the complex problem of preterm birth, and such is the work of the Preterm Birth and Healthy Outcomes Team (PreHOT).

Preterm birth impacts about 9.6% of pregnancies worldwide [1,2]. Preterm birth is the major cause of neonatal death, accounting for 25-50% of deaths of infants without congenital anomalies – a total of 1 million deaths world-wide annually [1,2]. Preterm birth is also responsible for the majority of newborn morbidity including cerebral palsy, cognitive impairment, blindness, deafness, respiratory illness and complications of neonatal intensive care [3]. Together these contribute to the loss of over 100 million disability-adjusted life-years [2]. The March of Dimes estimates the cost of preterm birth in the United States to be $26 billion annually [4]. In Canada, the Canadian Institute for Health Information estimates hospital costs alone for the care of very premature babies (<28 weeks) to be more than $100 million, whereas the total long-term costs are estimated at $13.3 billion per year [5]. In addition to the basic economic costs, attending to the needs of a child with a disability requires time, care and attention from families, extended families, health care systems, schools and public services. The conscious and unconscious dreams of parents and grandparents are revisited and often revised with the delivery of a preterm baby. Preterm birth influences not just the child, but the entire family’s well being and quality of life.

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

Brenda M.Y. Leung, Sheila W. McDonald, Bonnie J. Kaplan, Gerald F. Giesbrecht, and Suzanne C. Tough

 

Background: 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).

Methods: 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.

Results: The pregnancy cohorts differed in education, income, ethnicity, and foreign-born status (p < 0.01), but were similar for maternal age, BMI, and marital status. Compared to the MES, the lowest age, education, and income groups were under-represented, and the cohorts were more likely to be primiparous.

Conclusions: The findings suggest that non-stratified strategies for recruitment of participants will not necessarily result in samples that reflect the general population, but can reflect the target population of interest. Attracting and retaining young, low resource women into urban studies about pregnancy may require alternate and innovative approaches.

Increasing the quality of life from womb to grave: the importance of pregnancy and birth cohorts

 Bonnie J. Kaplan, Brenda M. Leung, Gerald F. Giesbrecht, Catherine J. Field, Francois P. Bernier, Suzanne Tough, Xinjie Cui, Deborah Dewey and the APrON Study Team

 

Epigenetics is revealing how “nature is nurtured”, with environmental factors such as nutrition, environmental neurotoxicants, and psychological stress influencing DNA expression. In this current opinion paper, we argue that understanding the dynamic interplay between the genome acquired at conception and environmental exposures throughout life requires pregnancy and birth cohorts, and that greater Canadian national commitment to the infrastructure needed for sustaining such cohorts is warranted. We present a framework that is now being implemented in Alberta.

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

Sheila W. McDonald, Andrew W. Lyon, Karen M. Benzies, Deborah A. McNeil, Stephen J. Lye, Siobhan M. Dolan, Craig E. Pennell, Alan .D Bocking and Suzanne C. Tough

 

BACKGROUND: 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.

METHODS: 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.

RESULTS: A total of 4011 pregnant women were eligible for recruitment into the AOB study. Of this, 3388 women completed at least one survey. The majority of participants were less than 35 years of age, Caucasian, Canadian born, married or in a common-law relationship, well-educated, and reported household incomes above the Calgary median. Women who discontinued after the first survey (n=123) were typically younger, non-Caucasian, foreign-born, had lower education and household income levels, were less likely to be married or in a common-law relationship, and had poor psychosocial health in early pregnancy. In general, AOB participants reflect the pregnant and parenting population at local and provincial levels, and perinatal indicators from the study are comparable to perinatal surveillance data.

CONCLUSIONS: The extensive and rich data collected in the AOB cohort provides the opportunity to answer complex questions about the relationships between biology, early experiences, and developmental outcomes. This cohort will contribute to the understanding of the biologic mechanisms and social/environmental pathways underlying associations between early and later life outcomes, gene-environment interactions, and developmental trajectories among children.

 

Validation of Canadian mothers’ recall of events in labour and delivery with electronic health records

Uilst Bat-Erdene, Amy Metcalfe, Sheila W. McDonald, and Suzanne C. Tough

BACKGROUND: Maternal report of events that occur during labour and delivery are used extensively in epidemiological research; however, the validity of these data are rarely confirmed. This study aimed to validate maternal self-report of events that occurred in labour and delivery with data found in electronic health records in a Canadian setting.

METHODS: Data from the All Our Babies study, a prospective community-based cohort of women's experiences during pregnancy, were linked to electronic health records to assess the validity of maternal recall at four months post-partum of events that occurred during labour and delivery. Sensitivity, specificity and kappa scores were calculated. Results were stratified by maternal age, gravidity and educational attainment.

RESULTS: Maternal recall at four months post-partum was excellent for infant characteristics (gender, birth weight, gestational age, multiple births) and variables related to labour and delivery (mode of delivery, epidural, labour induction) (sensitivity and specificity >85%). Women who had completed a university degree had significantly better recall of labour induction and use of an epidural.

CONCLUSION: Maternal recall of infant characteristics and events that occurred during labour and delivery is excellent at four months post-partum and is a valid source of information for research purposes.

All Our Babies Cohort Study: recruitment of a cohort to predict women at risk of preterm birth through the examination of gene expression profiles and the environment

Sara K. Gracie, Andrew W. Lyon, Heather L. Kehler, Craig E. Pennell, Siobhan M. Dolan, Deborah A. McNeil, Jodi E. Siever, Sheila W. McDonald, Alan D. Bocking, Stephen J. Lye, Kathy M. Hegadoren, David M. Olson and Suzanne C. Tough

BACKGROUND: Preterm birth is the leading cause of perinatal morbidity and mortality. Risk factors for preterm birth include a personal or familial history of preterm delivery, ethnicity and low socioeconomic status yet the ability to predict preterm delivery before the onset of preterm labour evades clinical practice. Evidence suggests that genetics may play a role in the multi-factorial pathophysiology of preterm birth. 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.

METHODS/DESIGN: 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.

DISCUSSION: The All Our Babies Study is an example of how investment in clinical-academic-community partnerships can improve research efficiency and accelerate the recruitment and data collection phases of a study. Establishing these partnerships during the study design phase and maintaining these relationships through the duration of the study provides the unique opportunity to investigate the multi-causal factors of preterm birth. The overall All Our Babies Study results can potentially lead to healthier pregnancies, mothers, infants and children.