Double jeopardy-pregnancy and birth during a catastrophic bushfire event followed by a pandemic lockdown, a natural experiment

Bronwyn K Brew; Natasha Donnolley; Amanda Henry; Hannah Dahlen; Bin Jalaludin; Georgina M Chambers

doi:10.1016/j.envres.2022.113752

Double jeopardy-pregnancy and birth during a catastrophic bushfire event followed by a pandemic lockdown, a natural experiment

Environ Res. 2022 Nov;214(Pt 1):113752. doi: 10.1016/j.envres.2022.113752. Epub 2022 Jun 28.

Authors

Bronwyn K Brew¹, Natasha Donnolley², Amanda Henry³, Hannah Dahlen⁴, Bin Jalaludin⁵, Georgina M Chambers²

Affiliations

¹ National Perinatal Epidemiology and Statistics Unit, Centre for Big Data Research in Health & School of Clinical Medicine, UNSW, Australia. Electronic address: B.haasdyk@unsw.edu.au.
² National Perinatal Epidemiology and Statistics Unit, Centre for Big Data Research in Health & School of Clinical Medicine, UNSW, Australia.
³ Discipline of Women's Health, School of Clinical Medicine, UNSW, Australia; Department of Women's and Children's Health, St George Hospital, Kogarah, NSW, Australia.
⁴ School of Nursing and Midwifery, Western Sydney University, Australia.
⁵ Ingham Institute for Applied Medical Research, UNSW Sydney, Australia.

PMID: 35777439
DOI: 10.1016/j.envres.2022.113752

Abstract

Background: From November 2019 to January 2020, eastern Australia experienced the worst bushfires in recorded history. Two months later, Sydney and surrounds were placed into lockdown for six weeks due to the COVID-19 pandemic, followed by ongoing restrictions. Many pregnant women at this time were exposed to both the bushfires and COVID-19 restrictions.

Objective: To assess the impact of exposure to bushfires and pandemic restrictions on perinatal outcomes.

Methods: The study included 60 054 pregnant women who gave birth between November 2017 and December 2020 in South Sydney. Exposure cohorts were based on conception and birthing dates: 1) bushfire late pregnancy, born before lockdown; 2) bushfires in early-mid pregnancy, born during lockdown or soon after; 3) conceived during bushfires, lockdown in second trimester; 4) conceived after bushfires, pregnancy during restrictions. Exposure cohorts were compared with pregnancies in the matching periods in the two years prior. Associations between exposure cohorts and gestational diabetes, preeclampsia, hypertension, stillbirth, mode of birth, birthweight, preterm birth and small for gestational age were assessed using generalised estimating equations, adjusting for covariates.

Results: A decrease in low birth weight was observed for cohort 1 (aOR 0.81, 95%CI 0.69, 0.95). Conversely, cohort 2 showed an increase in low birth weight, and increases in prelabour rupture of membranes, and caesarean sections (aOR 1.18, 95%CI 1.03, 1.37; aOR 1.21, 95%CI 1.07, 1.37; aOR 1.10 (1.02, 1.18) respectively). Cohort 3 showed an increase in unplanned caesarean sections and high birth weight babies (aOR 1.15, 95%CI 1.04, 1.27 and aOR 1.16, 95%CI 1.02, 1.31 respectively), and a decrease in gestational diabetes mellitus was observed for both cohorts 3 and 4.

Conclusion: Pregnancies exposed to both severe climate events and pandemic disruptions appear to have increased risk of adverse perinatal outcomes beyond only experiencing one event, but further research is needed.

Keywords: Birth; Bushfire; COVID-19; Pandemic; Perinatal; Pregnancy; Wildfire.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

COVID-19*
Communicable Disease Control
Diabetes, Gestational*
Female
Humans
Infant, Newborn
Pandemics
Pregnancy
Pregnancy Outcome
Premature Birth*