In this study, the authors reported a case of woman with severe compulsion who became pregnant during the Repetitive transcranial magnetic stimulation. We carried out Repetitive transcranial magnetic stimulation and behavior therapy simultaneously after repeated medications' refraction. The patient received 20 sessions 1 Hz Repetitive transcranial magnetic stimulation in right dorsolateral prefrontal cortex and behavior therapy at the same time in repetitive transcranial magnetic stimulation room. We asked the patient to exposure her fear and without permission of doing usual behavior (washing), she was receiving repetitive transcranial magnetic stimulation. Repetitive transcranial magnetic stimulation and Behavior Therapy could reduce her symptoms significantly. Although her baby was healthy physically but some areas of Age and Stage Questionnaire were below than the average. Repetitive transcranial magnetic stimulation with an additional psychotherapy as behavior therapy could accelerate the improvement of Obsessive compulsive disorder's symptoms. Furthermore, using Repetitive transcranial magnetic stimulation during the first of trimester probably couldn’t be safe for pregnant woman.