Objective: The psychopathology of pregnancy denial is under-researched. We hypothesized that mothers’ insecure attachment styles may increase vulnerability to pregnancy denial. Design: Prospective, multicentre case-control study. Setting: France. Population: 71 case dyads (D+) and 71 control dyads (D-) at inclusion; 70 dyads at 8 weeks postpartum (D+: 24, D-: 46). Methods: Data were collected 8 weeks postpartum through self-questionnaires and structured clinical assessment evaluating mothers’ attachment style representation (Attachment Script Assessment [ASA]), personality traits (International Personality Disorders Examination [IPDE]), psychiatric profiles (Beck Depression Inventory II [BDI-II], State-Trait Anxiety Inventory [STAI-Y], Edinburgh Postnatal Depression Scale [EPDS]), and socio-medical profiles. Main Outcome Measures: mothers’ attachment style representation between the two groups. Results: Based on the ASA, D+ mothers displayed significantly more insecure attachment style representation: median scores of 2.50 in the D+ group and 3.38 in the D- group. D+ dyads had more frequent indices of social disadvantage, especially in terms of house accommodations and marital status. Difference between the two groups were not statistically significant for EPDS postnatal depression score, BDI depression score, STAI anxiety score; while D+ women exhibited on average higher borderline and paranoid traits based on the IPDE screening. Conclusions: D+ mothers tend to exhibit more insecure attachment style representations, longstanding personality dysfunction, greater social vulnerability without differences in terms of associated emotional symptoms. Identifying mothers with insecure histories is crucial for psychosocial support.