Interpregnancy interval and adverse birth outcomes: a population-based cohort study of twins

BACKGROUND

To investigate associations between interpregnancy intervals (IPIs) and adverse birth outcomes in twin pregnancies.

METHODS

This retrospective cohort study of 9,867 twin pregnancies in Western Australia from 1980-2015. Relative Risks (RRs) were estimated for the interval prior to the pregnancy (IPI) as the exposure and after the pregnancy as a negative control exposure for preterm birth (< 37 weeks), early preterm birth (< 34 weeks), small for gestational age (SGA: < 10th percentile of birth weight by sex and gestational age) and low birth weight (LBW: birthweight < 2,500 g).

RESULTS

Relative to IPIs of 18-23 months, IPIs of < 6 months were associated with a higher risk of early preterm birth (aRR 1.41, 95% CI 1.08-1.83) and LBW for at least one twin (aRR 1.16, 95% CI 1.06-1.28). IPIs of 6-11 months were associated with a higher risk of SGA (aRR 1.24, 95% CI 1.01-1.54) and LBW for at least one twin (aRR 1.09, 95% CI 1.01-1.19). IPIs of 60-119 months and ≥ 120 months were associated with an increased risk of preterm birth (RR 1.12, 95% CI 1.03-1.22; and (aRR 1.25, 95% CI 1.10-1.41, respectively), and LBW for at least one twin (aRR 1.17, 95% CI 1.08-1.28; and aRR 1.20, 95% CI 1.05-1.36, respectively). IPIs of ≥ 120 months were also associated with an increased risk of early preterm birth (aRR 1.42, 95% CI 1.01-2.00). After negative control analysis, IPIs ≥ 120 months remained associated with early preterm birth and LBW.

CONCLUSION

Evidence for adverse associations with twin birth outcomes was strongest for long IPIs.

Wildfire smoke exposure during pregnancy and perinatal, obstetric, and early childhood health outcomes: A systematic review and meta-analysis

BACKGROUND

Maternal exposure to air pollution during pregnancy is associated with adverse birth outcomes, although less is known for wildfire smoke. This systematic review evaluated the association between maternal exposure to wildfire smoke during pregnancy and the risk of perinatal, obstetric, and early childhood health outcomes.

METHODS

We searched CINAHL Complete, Ovid/EMBASE, Ovid/MEDLINE, ProQuest, PubMed, Scopus, Web of Science, and Google Scholar to identify relevant epidemiological observational studies indexed through September 2023. The screening of titles, abstracts, and full-texts, data extraction, and risk of bias assessment was performed by pairs of independent reviewers.

RESULTS

Our systematic search yielded 28,549 records. After duplicate removal, we screened 14,009 studies, identifying 31 for inclusion in the present review. Data extraction highlighted high methodological heterogeneity between studies, including a lack of geographic variation. Approximately 56.5% and 16% originated in the United States and Brazil, respectively, and fewer in other countries. Among the studies, wildfire smoke exposure during pregnancy was assessed using distance of residence from wildfire-affected areas (n = 15), measurement of air pollutant concentration during wildfires (n = 11), number of wildfire records (n = 3), aerosol index (n = 1), and geographic hot spots (n = 1). Pooled meta-analysis for birthweight and low birthweight were inconclusive, likely due to low number of methodologically homogenous studies. However, the reviewed studies provided suggestive evidence for an increased risk of birthweight reduction, low birthweight, preterm birth, and other adverse health outcomes.

CONCLUSIONS

This review identified 31 studies evaluating the impacts of maternal wildfire smoke exposure on maternal, infant, and child health. Although we found suggestive evidence of harm from exposure to wildfire smoke during pregnancy, more methodologically homogenous studies are required to enable future meta-analysis with greater statistical power to more accurately evaluate the association between maternal wildfire smoke and adverse birth outcomes and other health outcomes.

Association between preschooler outdoor play and home yard vegetation as measured by high resolution imagery: Findings from the PLAYCE study

Outdoor play in the home yard is an important source of physical activity for many preschoolers. This study investigated if home yard size and vegetation are related to preschooler outdoor play time. High-resolution remotely sensed data were used to distinguish between types of vegetation coverage in the home yard. Shrub and tree cover, and yard size, were positively associated with outdoor play. Following stratification by socio-economic status (SES - parent education), only tree cover was positively associated with preschooler outdoor play in low SES households. All types of vegetation cover were positively associated with preschooler outdoor play in higher SES households. This study highlights the importance of larger yard sizes and higher levels of vegetation for facilitating outdoor play in preschoolers.

The built environment and child obesity: A review of Australian policies

Child obesity is a serious public health challenge affected by both individual choice and societal and environmental factors. The main modifiable risk factors for child obesity are unhealthy eating and low levels of physical activity, both influenced by aspects of the built environment. Coordinated government policy across jurisdictions, developed using strong research evidence, can enable built environments that better support healthy lifestyles. This study reviewed current Australian and Western Australian government policies to understand if and how they address the impact of the built environment on child obesity, physical activity, sedentary behavior, and diet. Current government policy documents related to the built environment and child health were analyzed using the Comprehensive Analysis of Policy on Physical Activity framework. Ten Australian and 31 Western Australian government policy documents were identified. Most referred to the role of the built environment in supporting physical activity. Very few policies mentioned the built environment's role in reducing sedentary behaviors, supporting healthy eating, and addressing obesity. Few recognized the needs of children, and none mentioned children in policy development. Future government policy development should include the voices of children and child-specific built environment features. Inter-organizational policies with transparent implementation and evaluation plans are recommended.

Built Environments And Child Health in WalEs and AuStralia (BEACHES): a study protocol

INTRODUCTION

Childhood obesity and physical inactivity are two of the most significant modifiable risk factors for the prevention of non-communicable diseases (NCDs). Yet, a third of children in Wales and Australia are overweight or obese, and only 20% of UK and Australian children are sufficiently active. The purpose of the Built Environments And Child Health in WalEs and AuStralia (BEACHES) study is to identify and understand how complex and interacting factors in the built environment influence modifiable risk factors for NCDs across childhood.

METHODS AND ANALYSIS

This is an observational study using data from five established cohorts from Wales and Australia: (1) Wales Electronic Cohort for Children; (2) Millennium Cohort Study; (3) PLAY Spaces and Environments for Children's Physical Activity study; (4) The ORIGINS Project; and (5) Growing Up in Australia: the Longitudinal Study of Australian Children. The study will incorporate a comprehensive suite of longitudinal quantitative data (surveys, anthropometry, accelerometry, and Geographic Information Systems data) to understand how the built environment influences children's modifiable risk factors for NCDs (body mass index, physical activity, sedentary behaviour and diet).

ETHICS AND DISSEMINATION

This study has received the following approvals: University of Western Australia Human Research Ethics Committee (2020/ET000353), Ramsay Human Research Ethics Committee (under review) and Swansea University Information Governance Review Panel (Project ID: 1001). Findings will be reported to the following: (1) funding bodies, research institutes and hospitals supporting the BEACHES project; (2) parents and children; (3) school management teams; (4) existing and new industry partner networks; (5) federal, state and local governments to inform policy; as well as (6) presented at local, national and international conferences; and (7) disseminated by peer-reviewed publications.

Is early childhood development impeded by the birth timing of the younger sibling?

Background

This study investigated whether the timing of birth of the younger siblings was associated with the risk of the older siblings’ developmental vulnerability in early childhood.

Methods

Linkage of population-level birth registration, hospital, and perinatal datasets to Australian Early Development Census (AEDC) records (2009–2015), enabled follow-up of a cohort of 32,324 Western Australia born singletons. Children with scores <10^th percentile on an individual AEDC domain (Physical Health and Wellbeing; Social Competence; Emotional Maturity; Language and Cognitive Skills (school-based); and Communication Skills and General Knowledge) were classified as developmentally vulnerable. Modified Poisson Regression was used to estimate relative risks (RR) for associations between post-birth interpregnancy intervals (IPIs) and developmental vulnerability.

Results

Relative to post-birth IPIs of 18–23 months, post-birth IPIs of <6 and 6–11 months were associated with an increased risk of children being classified as DV1 (aRR 1.21, 95% CI: 1.11–1.31) and DV2 (aRR 1.31, 95% CI: 1.15–1.49); and DV1 (aRR 1.10, 95% CI: 1.03–1.17) and DV2 (aRR 1.21, 95% CI: 1.09–1.34), respectively. Post-birth IPIs of <6 months were associated with an increased risk on four of the five AEDC domains. Post-birth IPIs of 48–60 months were associated with an increased risk of developmental vulnerability; however, the risk was statistically significant for DV1, DV2 and the domains of Emotional Maturity and Language and Cognitive Skills (school-based).

Conclusions

Developmental vulnerability was associated with having a closely spaced younger sibling (<12 months post-birth IPIs). Optimising birth spacing should be further investigated as a potential means for improving child development outcomes.

Prevalence and risk factors of adverse birth outcomes in the Pacific Island region: A scoping review

Background

Prevalence and exposures of adverse birth outcomes is well studied in low-and-middle-income countries but not well-established for the Pacific Island region. Our study mapped the available evidence on low birth weight (LBW), preterm birth, and small for gestational age (SGA)’s prevalence and their corresponding risks in the region.

Methods

We followed the five-staged Arksey and O'Malley's framework with clinicians’ consultation in the region. Five scholarly databases and non-indexed studies were searched and extracted data were analysed as numerical and thematic summaries mapping the outcomes and exposures.

Findings

We included 20 studies representing 11 Pacific Island countries with the following mean prevalence and associations at 95% confidence interval. Estimated mean prevalence for LBW and preterm births were 12% and 13%, respectively. LBW were associated with malaria in pregnancy [aOR 3.3 (1.00, 10.60)], and betel nut and tobacco [aOR 2.4 (1.00, 6.00)]. Preterm births were associated with malaria in pregnancy [aOR 6.6 (2.46, 17.62)] and maternal obesity [aOR 1.5 (1.00, 2.30)]. SGA were associated with short stature [aOR 1.7 (1.22, 2.41)] and no antenatal bookings [aOR 4.0 (2.12, 7.57)]

Interpretation

Several significant factors identified were malaria infection, obesity, betel nut and tobacco and no antenatal care, also validated by clinicians consulted.

Funding

Australia National Health and Medical Research Council.

The effects of birth spacing on early childhood development in high-income nations: A systematic review

OBJECTIVE

This study aimed to systematically review the literature on the associations between birth spacing and developmental outcomes in early childhood (3-10 years of age). Studies examining the associations between interpregnancy intervals and child development outcomes during and beyond the perinatal period have not been systematically reviewed.

METHODS

We searched Ovid/MEDLINE, Global Health, PsycINFO, EMBASE, CINAHL Plus, Educational Source, Research Starters, ERIC, Scopus, PubMed, Social Science Research Network database, and ProQuest's Social Sciences Databases for relevant articles published between 1 January 1989 and 25 June 2021. Studies published in English, conducted in populations residing in high-income countries with any measure of birth spacing, and child development outcomes among children aged <10 years were included. Two authors independently assessed the eligibility of studies and extracted data on the study design, setting and population, birth spacing, outcomes, and results.

RESULTS

The search yielded 1,556 records, of which seven studies met the inclusion criteria. Five of these seven studies used birth intervals as the exposure measure. Definitions of exposure differed between the studies. Three studies reported an association between short birth spacing and poorer child development outcomes, and two studies reported an association between long birth spacing and poorer child development outcomes.

CONCLUSION

Currently, limited evidence suggests that the adverse effects of sub-optimal birth spacing are observable beyond infancy.