To estimate the frequency of Positive Maternal Mental Health (PMMH) interpretation levels in pregnant women who attended prenatal consultation and to identify their association with obstetric and psychosocial factors.A cross-sectional study that included pregnant women who attended prenatal care at 12 or more weeks of gestation. The following scales were applied: Positive Mental Health Questionnaire (PMHQ), Goldberg Anxiety and Depression Scale, and Jong Gierveld Loneliness Scale.702 pregnant women were evaluated; 634 (90.3%) had flourishing PMMH, and 68 (9.7%) had non-flourishing PMMH. Among the latter, all were at an intermediate level, and none were languishing. Flourishing PMMH was more frequent in adults (91.2%) compared to adolescents (75.0%) and in women with higher education (93.0%) than in those with basic education (83.9%). The PMHQ factors and global score correlated positively with maternal age and negatively with anxiety, depression, emotional, social, and general loneliness. Associated with a higher frequency of non-flourishing PMMH were general loneliness OR:6.32[CI95%:3.38-11.82], social loneliness OR:5.98[CI95%:3.42-10.42], adolescence OR:3.47[CI95%:1.61-7.45], emotional loneliness OR:3.12[1.83-5.32], anxiety OR:2.14[CI95%:1.27-3.60], and depression OR:1.88[CI95%:1.09-3.25]. Less frequently: work occupation outside the home OR:0.41[CI95%:0.24-0.68], technical/technological studies OR:0.22[CI95%:0.08-0.60] and university OR:0.27[CI95%:0.10-0.71]. Preconception consultation, desired pregnancy, cesarean section, and fetal or neonatal death were not associated. In the adjusted model: general loneliness OR:3.02[CI95%:1.10-8.31], social loneliness OR:2.82[CI95%:1.38-5.79] and anxiety OR:1.93[CI95%:1.02-3.67], retained statistical significance.Nine out of ten pregnant women had flourishing PMMH, and none had languishing PMMH. None of the obstetric factors were associated with non-flourishing PMMH but with general loneliness, social loneliness, and anxiety.