The Fukushima nuclear power plant accident created many challenges, including those for families with small children who sought to assess and address the health risks of radiation exposure. Mothers’ worries about their young children have been described in prior studies, but none has examined the impact of a nuclear power accident on their self-confidence as mothers. The present study focused on levels and associated factors of maternal confidence (one of the indicators used to evaluate Japan’s national Maternal and Child Health Plan) before and after the accident. Comparing three samples of mothers with 18-month-old children in Fukushima City (218 in 2010
300 in 2011, the year of the accident
and 188 in 2012) indicated that maternal confidence was lower in 2011 compared to 2010 and 2012. Interpersonal problems at home were significantly associated with lower maternal confidence in 2011, as well as increased depression in 2012. Other factors associated with lower maternal confidence across these 3 years were poorer perceived health and first-time motherhood. Suggested strategies include giving special attention to maternal confidence after nuclear disasters, as well as continuous monitoring of maternal confidence and a focus on mothers’ interpersonal issues. Improving access to health information is one key to supporting maternal confidence after a disaster occurs.