Purpose Internalizing problems during and after pregnancy are important for parenting and child outcomes. The study aimed to understand correlates (i.e., marital satisfaction, co-parenting) of maternal internalizing problems during pregnancy with a second child. Method We investigated levels of depression, anxiety, and stress symptoms of mothers in the third trimester of pregnancy with their second children. Fifty-one mothers and their firstborn children were visited in their homes and mothers completed questionnaires. Results Results showed that co-parenting and marital satisfaction were related to internalizing outcomes. More specifically, co-parenting predicted depression ?and stress ?when controlling for marital satisfaction, whereas marital satisfaction predicted anxiety over co-parenting. Conclusion The findings highlight the importance of studying prenatal internalizing problems differentially and can inform future intervention studies to prevent poor psychological outcomes.