The COVID-19 pandemic has exacerbated pre-existing gender inequality in Brazil and around the world. The effects on women's work and domestic lives have been dramatic, leading to challenges not yet fully clarified, especially for mothers of children under the age of 18. This article aimed to verify the association between these women's perception of dealing with motherhood and sociodemographic factors, work situation, emotional conditions, and changes in the behavior and development of their children during the pandemic. A cross-sectional quantitative study was carried out, and an online questionnaire was applied to 28,625 mothers from all over Brazil. There was a higher prevalence of difficulty in dealing with motherhood among white women, with an income greater than ten times the minimum wage, high school complete level, and children under the age of 6. The factors that had the greatest impact on the increased prevalence of difficulty were the rise in the domestic workload, changes in children's behavior, reduced social interaction between children and other kids, and having children under the age of 6. On the other hand, the improvement or maintenance of women's emotional condition, as well as the advancement in their children's development, decreased the perception of difficulty in dealing with maternity.