Objective: This study examines the extent to which the experience of parenthood worries among Finnish firsttime parents predicts the probability of a second birth, and whether the associations differ according to the parent's gender or the sufficiency of spousal support in parenting. Background: First-time parents' withdrawal from having a second child has been connected to declining fertility rates in Finland and many other high -income countries; consequently, more understanding is needed about why parents potentially refrain from subsequent childbearing. Method: We utilize longitudinal survey data collected from Finnish parents ( N = 544) in three waves (2016- 2020). Results: The results show that experiencing parenthood worries significantly predicts the probability of a second birth. Specifically, the accumulation of parenthood worries predicted a lower probability of a second birth, and each additional worry decreased the probability significantly more for fathers compared to mothers. Although we found no gender differences regarding the associations between specific parenthood worries and the probability of a second birth, our results showed that fathers who worried about loneliness or having sole responsibility for parenting were less likely to have a second child than fathers with no such worries. In terms of the sufficiency of spousal support in parenting, we found, first, that among parents who received insufficient spousal support, those who worried about their parenting skills adequacy had a lower probability of a second birth than those with no such worries. Second, among parents with sufficient spousal support, worrying about their own ability to cope was associated with decreased probability of a second birth compared to those who did not experience such worry. Conclusion: Our findings provide new insights into the potential influence of parenthood worries experienced by first-time parents and the role of spousal support in subsequent childbearing.