The objective of this study was to determine whether childbirth education conducted over 3 or more sessions is more effective than courses conducted over 1 or 2 sessions. This was a secondary analysis of 2853 participants in a longitudinal study of women recruited during their first pregnancy. Data on childbirth education attendance were collected during the 1-month postpartum interview. The Kruskal-Wallis test for ranks was used for univariate analysis by the number of class sessions, and logistic regression was used to compare no education with any childbirth education, single-session, 2-session, and 3-or-more-session courses. Primary outcomes included induction of labor, cesarean delivery, use of pain medication, and shared decision-making. Attending 3 or more education sessions was associated with a decreased risk of planned cesarean delivery and increased shared decision-making. Attending any childbirth education was associated with lower odds of using pain medication in labor, reduced odds of planned cesarean delivery, and increased shared decision-making.