Aim
The receipt of long-term financial social assistance (FSA) as an indicator of financial difficulties among Finnish youth with prenatal substance exposure (PSE) was investigated in comparison with unexposed youth.

Methods
Data from national health and social welfare registers were collected for 18–24-year-old exposed (n = 355) and unexposed (n = 1011) youth. The influence of youth and maternal characteristics and out-of-home care (OHC) on the association between PSE and youth’s long-term FSA receipt was studied by generalized linear models and mediation analyses.

Results
Exposed youth had an increased likelihood of long-term FSA receipt (OR 4.89, 95% CI 3.76, 6.37) but the difference with unexposed was attenuated following adjustments for youth and maternal characteristics and OHC (AOR 1.33, 95% CI 0.89, 1.98). Maternal long-term FSA receipt (0.48, 95% CI 0.35, 0.64) and OHC (0.63, 95% CI 0.47, 0.83) mediated a large proportion of the association between PSE and youth’s long-term FSA receipt. Youth’s mental or behavioral disorders partly mediated the association (0.21, 95% CI 0.14, 0.30), but the mediating effect of lack of secondary education was minor (0.03, 95% CI 0.01, 0.07).

Conclusion
Receipt of long-term FSA among youth with PSE likely reflects maternal substance abuse linked with maternal financial situation and care instability in childhood.