Materials and Methods: This clinical trial was performed in three hospitals of Mashhad in 2018. To this end, 52 drug-abusing mothers were randomly divided into experimental and control groups. The intervention protocol consisted of four separate training sessions with an emphasis on the theory of planned behavior. The follow-up process was performed 2 and 4 months after delivery, and the theory of planned behavior and breastfeeding continuity questionnaire was completed accordingly. Data were analyzed by the SPSS (version 16) using the independent t test and chi-square, Mann-Whitney, Friedman, and Wilcoxon tests.

Results: Two months after delivery, 88.5% and 3.8% of mothers of the intervention and control groups performed exclusive breastfeeding while this rate was 65.4% and 0.0% four months after delivery, respectively. The results of the chi-square test showed a significant difference between the two groups at 2 and 4 months (P < 0.001). Two months after delivery, the average score of maternal performance on the continuation of exclusive breastfeeding was 91.8 ± 9.2 and 50.8 ± 24.5 in the intervention and control group although it was 89.0±8.7 and 31.0±15.9 4 months after delivery, respectively. Based on the results of the Wilcoxon test, significant differences were found between the groups after 2 and 4 months (P < 0.001). Eventually, the average score of all constructs of the planned behavior theory improved immediately after the intervention, and 2 and 4 months after delivery in the intervention group (P < 0.001).

Conclusions: Thus, the implementation of breastfeeding training based on the theory of planned behavior is recommended for drug-dependent mothers to continue exclusive breastfeeding.