SUMMARY
Intellectual and developmental disabilities (IDD) are a heterogeneous group of disorders characterized by deficits
in cognitive and adaptive functioning, with onset before adulthood. Individuals with IDD face substantive social,
healthcare, and health disparities. In recent years, multiple studies have reported an increased risk of adverse
maternal, birth and infant outcomes associated with any IDD diagnosis. To date, the risk associated with specific
diagnoses and the underlying causes of these excess risks have not been elucidated, although researchers have
hypothesized that chronic disease, adverse reproductive factors such as smoking or inadequate prenatal care,
and pregnancy complications could explain the risk. Without quantifying these mediating pathways, it is unclear
where to target intervention efforts to optimize maternal and infant outcomes. To address this gap, we propose
a study with the overarching objective to (1) leverage large-scale administrative data to elucidate the factors
contributing to adverse maternal and infant outcomes for women with IDD, and (2) conduct causal
mediation analyses, accounting for multiple mediators, to establish empirically derived intervention
targets. In order to achieve this objective, we will do the following: characterize the pathways between IDD
subtypes and adverse maternal outcomes (Aim 1); characterize the pathways between IDD subtypes and
adverse birth and infant outcomes (Aim 2), quantify the multiple factors that mediate maternal and infant
outcomes among women with IDD diagnoses (Aim 3). We will use data from the Study of Mothers and Infants,
an administrative birth cohort consisting of all live born (n=6.7 million) and stillborn (n=26,922) deliveries in
California between 2007-2021 in which birth records are linked to maternal and infant hospital summaries, infant
and fetal death records, and in a subset, California Medicaid records. This will allow us to perform causal
mediation analyses to quantify the extent to which chronic comorbidities, reproductive factors, or prescription
medications mediate associations between IDD subtypes and adverse maternal and birth outcomes. Through
this research, we will greatly expand the conceptual framework of reproductive health in women with IDD,
allowing for targeted interventions to be interrogated in future work.
