Evidence regarding how dispositional traits, antenatal anxiety, substance use, and obstetric events converge to shape post-partum depression (PPD) in South-East Europe is limited. We analysed 102 third-trimester women and followed them to six weeks post-partum, and 102 age-matched community controls were used to (i) compare baseline psychological profiles, (ii) chart antenatal-to-post-partum symptom trajectories, and (iii) build an integrated model of clinically relevant PPD (Edinburgh Post-natal Depression Scale, EPDS ≥ 12). All 96 raw variables were forward-backward translated from Romanian, reconciled, and harmonized. The principal instruments used were EPDS, State-Trait Anxiety Inventory form Y (STAI-Y), Revised Obsessive-Compulsive Inventory (OCI-R), NEO Five-Factor Inventory (NEO-FFI-60), and the four-item Maternal Worry and Satisfaction Scale (MWSS). Groups were age-matched (31.1 ± 5.4 vs. 30.3 ± 5.1 years, = 0.268) but differed in urban residence (39% vs. 17%, = 0.001) and current substance use (smoking 21% vs. 34%, = 0.041; alcohol 6% vs. 22%, = 0.002). Of five personality domains, only openness scored lower in peripartum women (26.1 ± 4.6 vs. 29.3 ± 5.2, < 0.001). State anxiety rose significantly from pregnancy to puerperium (+5.1 ± 8.4 points, < 0.001). Post-partum EPDS correlated most strongly with state anxiety (r = 0.62) and neuroticism (r = 0.50). A final model (pseudo-R = 0.30) identified post-partum state anxiety (OR 1.10 per point, 95% CI 1.05-1.15, < 0.001) as the independent predictor; neuroticism showed a trend (OR 1.08, = 0.081). Obstetric factors (prematurity, birth weight, caesarean section) were not significant. In this Romanian cohort, heightened state anxiety-in synergy with high neuroticism and lower openness-dominated the risk landscape of early onset PPD, whereas delivery mode and neonatal status were neutral. Routine perinatal mental health screening should therefore incorporate anxiety metrics alongside depression scales and brief trait inventories to refine preventive targeting.