Adolescent pregnancy is associated with poor health and socioeconomic factors. The adolescent pregnancy rate in Mexico is the highest among the Organization for Economic Co-operation and Development (OECD) countries. We aimed to explore the factors associated with pregnancies and births in adolescent and young adult women. Using the 2015 Mexican National Survey of Boys, Girls, and Women (ENIM), we examined two dichotomous outcomes: "ever pregnant" and "being a mother" in women from 15 to 19 years and from 20 to 24 years without pregnancies during adolescence. We conducted bivariate analysis for each age group and used general linear models (GLM) to assess the association between the outcome variables and selected socioeconomic variables. Among adolescents, school attendance and tertiary education significantly decreased the likelihood of ever having been pregnant or being mothers, while being married/cohabiting increased the likelihood. Older age at first intercourse was negatively associated with ever having been pregnant. For adult women, in addition to school attendance, tertiary education, and being married/cohabiting, the region of residence also showed a significant association with ever having been pregnant. Similar socioeconomic factors were associated with pregnancy and motherhood between adolescents and young adults. However, it was found that delaying sexual debut could reduce the adolescent pregnancy rate. Our results highlight the importance of attending school and attaining tertiary education in reducing adolescent fertility rates.