The influence of environmental exposures during the preconception period on offspring outcomes: A systematic review

Amie Steel^1*Wen Lee²Zhiwei Xu³Jenny Carè¹Javier Ramirez⁴Carrie Thomson-Casey¹Dwan Vilcins²

• ¹University of Technology Sydney, Sydney, Australia
• ²The University of Queensland, Brisbane, Australia
• ³Griffith University, Brisbane, Australia
• ⁴Queensland University of Technology, Brisbane, Australia

Introduction: Health behaviours and exposures to environmental hazards among individuals of reproductive age prior to pregnancy can influence maternal and child health outcomes. While research attention has focused on preconception health behaviours, such as diet and lifestyle, there is emerging evidence that environmental exposures may also be important to consider.A search strategy (PROSPERO # CRD42021240069) was developed for MEDLINE (OVID), EMBASE (OVID), Maternity and Infant Care (OVID), CINAHL (EBSCO), and PsycINFO (EBSCO). Searches were conducted from database inception until 21 May 2021. Studies were included that investigated male or female exposure to any environmental hazard during the preconception period and reported neonatal or child health outcomes. No limit to date of publication, language or comparator were applied. Studies were critically appraised using the Newcastle-Ottawa Quality Assessment Scale for Cohort studies.The review identified 63 studies that met the inclusion criteria, published between 1974 and 2021. They encompassed studies that covered ambient exposures (n=23), chemical exposures (n=26), and other exposures (n=24). For ambient exposures, all studies examined the outcomes associated with air pollution and one study also explored associations with exposure to hot and cold ambient temperature. Studies investigating chemical exposures encompassed endocrine-disrupting chemicals (n=4), pesticides (n=10), persistent organic pollutants (n=4), and organic solvents (n=7). Other exposures studied were categorised as radiation (n=9), metals (n=4) and undifferentiated products or compounds (n=14). Outcomes measured by the included studies covered congenital malformations, adverse birth outcomes and childhood illness. There was a high level of heterogeneity across the included studies that precluded meta-analysis. Various associations between exposures and outcomes were identified.Discussion: There is growing evidence of adverse outcomes in offspring associated with maternal and paternal environmental exposures during the pre-conception period. While there are some topics that have received focused attention from research teams in the last 50 years, most studies appear to be standalone and have not continued to develop as part of wider research programs. There is need to develop a field-wide approach to create an agenda for environmental preconception health exposures and outcomes that supports more coordinated, targeted and strategic research efforts.