Objective: To identify factors related to parental stress of women during pregnancy and the child’s first month of life. Method: Prospective longitudinal study in two stages. Analysis of home interviews with 121 participants, Gestational Stress Scale, and Parental Stress Scale. Fisher’s exact test, Spearman’s correlation, and linear and logistic multivariate regression were applied, with p < 0.05. Results: Most of the participants were between 18 and 35 years old, had 11 to 13 years of education, had no paid work, had a partner, usually the child’s father, planned pregnancy, were multiparous, and underwent prenatal care. During pregnancy, 67.8% had stress. In the first month after the child’s birth, most had low parental stress (52.1%). High parental stress correlated with some gestational stress. Planning pregnancy decreased parental stress. Conclusion: Gestational and parental stress in the child’s first month of life were correlated and pregnancy planning was a factor that reduced stress levels. Timely actions to reduce parental stress are essential for parenting and the child’s overall health.