Are Associations Between Guideline-Discordant Gestational Weight Gain and Perinatal Outcomes Modified by Area-Level Income? A Population-Based Retrospective Cohort Study of Pregnant Individuals in Nova Scotia.

Abstract

Gestational weight gain (GWG) below or above the current guideline recommendations is associated with delivery and neonatal complications. The role of area-level income (ALI) in modifying these associations has not been investigated. A population-based retrospective cohort study of 155,575 singleton deliveries in Nova Scotia from 2004– 2022 assessed whether ALI modifies the association between guideline-discordant GWG and preterm delivery (PTD), small and large for gestational age (SGA, LGA), shoulder dystocia (SD), and cesarean delivery (CD). Modified Poisson regression was used to assess effect measure modification on both multiplicative and additive scales. Guideline- discordant GWG was associated with increased risk of PTD, SGA, and LGA but not with SD or CD, with no heterogeneity in the risk ratios across ALI quintiles. However, ALI modified the association between guideline-discordant GWG and SGA on the additive scale. Limiting guideline-discordant GWG could play a role in reducing delivery and neonatal complications across all ALI categories.