Postpartum low-molecular-weight heparin (LMWH) thromboprophylaxis is indicated for a substantial proportion of women. We assessed women's adherence to postpartum thromboprophylaxis and the factors associated with adherence. This retrospective cohort study was conducted at a university hospital during 2018. Parturients for whom a recommendation for LMWH prophylaxis was given at discharge from the maternity ward were contacted at the end of the recommended post-discharge course of LMWH, and were invited to participate in a telephone survey. The main outcome measures were optimal (> 80%) and suboptimal adherence (< 80%) to LMWH administration, reasons for nonadherence, and views regarding LMWH, as assessed by an adapted Beliefs about Medication Questionnaire. Overall, 250 women completed the questionnaire. The median recommended duration of post-discharge LMWH was 7 [5-8] days. Suboptimal adherence was reported by 82 (32.8%); 45 (18.0%) women did not administer any LMWH dose following discharge and only 147 (58.8%) completed the full LMWH course. In multivariate analysis, patients' perceptions of the necessity of LMWH [odds ratio (95% CI): 3.50 (2.12, 9.53), P = 0.002] and of the adequacy of the explanation given prior to discharge regarding LMWH technical administration [odds ratio (95% CI): 5.0 (2.33, 11.11), P < 0.001] were positively associated with optimal adherence. Nearly one-third of women prescribed postpartum LMWH thromboprophylaxis reported suboptimal adherence. Patients' perceptions of the necessity of the treatment and their opinion of the adequacy of explanation regarding LMWH technical administration were identified as predictors of treatment compliance, and thus represent potential areas for improvement.