Preconception mental health and the relationship between antenatal depression or anxiety and gestational diabetes mellitus: a population-based cohort study

Background Antenatal depression and anxiety are highly prevalent conditions that have been associated with increased risk for myriad adverse outcomes. Current literature exploring the connection between antenatal mental health and gestational diabetes mellitus (GDM) is limited, presenting conflicting evidence. We sought to evaluate the association between antenatal depression/anxiety (DEP-ANX) and GDM using population-based, administrative data, accounting for aspects of preconception mental health. Methods In this population-based retrospective cohort study, we included all singleton births in British Columbia, Canada from April 1, 2000, to December 31, 2014. We identified instances of DEP-ANX from outpatient and inpatient records that included relevant diagnostic codes and stratified our cohort by preconception DEP-ANX persistence. Logistic regression models were run to estimate odds of GDM given antenatal DEP-ANX. Models were adjusted for the birthing person's socio-demographics and pregnancy characteristics. Using an expanded cohort, we ran conditional logistic regression models that matched birthing people to themselves (in a subsequent pregnancy) based on discordance of exposure and outcome. Results Out of the 228,144 births included in this study, 43,664 (19.1%) were to birthing people with antenatal health service use for DEP-ANX. There were 4,180 (9.6%) cases of GDM among those antenatal exposure to DEP-ANX compared to 15,102 (8.2%) among those without exposure (SMD 0.049). We observed an unadjusted odds ratio (OR) of 1.19 (95% CI: 1.15 - 1.23) and fully adjusted OR of 1.15 (95% CI: 1.11 - 1.19) overall. Apparent risk for GDM given antenatal DEP-ANX was highest among the no DEP-ANX history stratum, with a fully adjusted OR of 1.24 (95% CI: 1.15 - 1.34). Associations estimated by matched sibling analysis were non-significant (fully adjusted OR 1.19 [95% CI: 0.86 - 1.63]). Conclusions Results from this population-based study suggest an association between antenatal DEP-ANX and GDM that varied based on mental health history. Our analysis could suggest that incident cases of DEP-ANX within pregnancy are more closely associated with GDM compared to recurring or chronic cases.