To examine associations of household food insecurity with health and obesogenic behaviours among pregnant women enrolled in an obesity prevention programme in the greater Boston area.

Cross-sectional evaluation. Data were collected from structured questionnaires that included a validated two-item screener to assess household food insecurity. We used separate multivariable linear and logistic regression models to quantify the association between household food insecurity and maternal health behaviours (daily consumption of fruits and vegetables, sugar-sweetened beverages and fast food, physical activity, screen time, and sleep), mental health outcomes (depression and stress), hyperglycaemia status and gestational weight gain.

Three community health centres that primarily serve low-income and racial/ethnic minority patients in Revere, Chelsea and Dorchester, Massachusetts.

Totally, 858 pregnant women participating in the First 1,000 Days program, a quasi-experimental trial.

Approximately 21 % of women reported household food insecurity. In adjusted analysis, household food insecurity was associated with low fruit and vegetable intake (β = −0·31 daily servings; 95 % CI −0·52, −0·10), more screen time (β = 0·32 daily hours; 95 % CI 0·04, 0·61), less sleep (β = −0·32 daily hours; 95 % CI −0·63, −0·01), and greater odds of current (adjusted odds ratio (AOR) 4·42; 95 % CI 2·33, 8·35) or past depression (AOR 3·01; 95 % CI 2·08, 4·35), and high stress (AOR 2·91; 95 % CI 1·98, 4·28).

In our sample of mostly low-income, racial/ethnic minority pregnant women, household food insecurity was associated with mental health and behaviours known to increase the likelihood of obesity.