Objective: Idiopathic granulomatous mastitis (IGM) is an inflammatory and chronic benign breast disease that has proven difficult to diagnose and treat. Since most treatment modalities cannot be used in pregnant patients, the choice of treatment is more difficult and the need for surgery is more pressing. In this first and innovative study, we assess the results of local corticosteroid therapy of IGM in pregnant women.Materials and Methods: Pregnant women with IGM were evaluated between June 2017 and May 2019. The six pregnant women were treated using intralesional steroid injections and topical steroid administration. The treatment response was evaluated, both clinically and radiologically, at the end of 2 weeks and once more at the end of 1 month.Results: The median patient age was 26 years. The mean duration of complaints was 4.3 months. The median number of children was 2, and the mean breastfeeding time was 41 months. The predominant complaints at onset were a breast mass or local pain and inflammation in four (66.7%) patients and a breast mass with pain and without signs of local skin inflammation in two (33.3%) patients. Diagnosis was made using a tru-cut biopsy in two patients, and with an incisional biopsy in four patients who had abscess drainage and fistulation to the skin. Five (83.3%) patients achieved a complete response, and one (16.7%) patient responded only partially after the first course of treatment. A second course of treatment was given to the patient with partial response. All patients achieved complete response at the end of the second course of treatment. The mean follow-up time was 19.5 months. During the follow-up period, one patient experienced a recurrence at 4 months after giving birth, and she then received a third course of treatment. Topical and systemic side effects of the corticosteroids were not observed in any patient.Conclusion: While the state of pregnancy generally precludes the use of most drugs, the use of local corticosteroid in the treatment of IGM is effective in terms of treatment response, treatment duration, need for surgery, and reduced recurrence and side effects.