BackgroundAntenatal care (ANC) and facility delivery are essential maternal health services, but uptake remains low in northwestern Nigeria. To increase service use, social and behavior change (SBC) programs target psychosocial influences across cognitive, emotional and social domains including knowledge, beliefs, self-efficacy, and social norms. Yet there remains limited research that measures and quantitatively examines the role of psychosocial influences on pregnancy and childbirth behaviors in Nigeria or elsewhere. MethodsA cross-sectional population-based survey of randomly sampled women with a child under two years was conducted in Kebbi, Sokoto and Zamfara states of northwestern Nigeria in September 2019. Women were asked about maternal health behaviors during their last pregnancy. New psychosocial metrics were developed using the Ideation Model of Strategic Communication and Behavior Change. Predicted probabilities for visiting ANC four or more times (ANC4+) and giving birth in a facility were derived using mixed-effects logistic regression models adjusted for ideational and sociodemographic variables.ResultsAmong 3,039 women, 23.6% (95% CI: 18.0%-30.3%) attended ANC4+ times and 15.5% (95% CI: 11.8%-20.1%) gave birth in a facility. Among women who did not attend ANC4+ times or have a facility-based delivery during their last pregnancies, the most commonly cited reasons were lack of perceived need (42% and 67%, respectively) and spousal opposition (25% and 27%, respectively). Women who knew any ANC benefit or the recommended number of ANC visits were 3.2- and 2.1-times more likely to attend ANC4+ times. Women who held positive views about health facilities for childbirth had 1.2- and 2.6-times higher likelihood of attending ANC4+ times and facility delivery, while women who believed ANC was only for sickness or pregnancy complications had 17% lower likelihood of attending ANC4+ times. Self-efficacy and supportive spousal influence were also significantly associated with both outcomes.ConclusionsTo improve pregnancy and childbirth practices in northwestern Nigeria, programs should address a range of psychosocial factors – across cognitive, emotional and social domains – that were significantly associated with pregnancy and childbirth behaviors: raising knowledge and dispelling myths, building women’s confidence to access services, engaging spousal support in decision-making, and improving perceived (and actual) maternal health services quality.