Safety and feasibility of repetitive transcranial magnetic stimulation (rTMS) as a treatment for major depression during pregnancy

Dear Editor, In the USA, the Food and Drug Administration has not approved any antidepressant drug to be used for pregnant women. Thus, it is important to find alternative therapies for depressed women during pregnancy (Ter Horst et al. 2008). As was demonstrated in recent reviews and meta-analysis, the efficacy of repetitive transcranial magnetic stimulation (rTMS) in treating major depression has been gradually recognized and accepted (Daskalakis et al. 2008). A 28-year-old woman was diagnosed with major depression according to DSM-IV criteria for major depressive episode. At a regularly scheduled clinic visit, she reported that she had recently become pregnant. Approximately 14 weeks into her pregnancy, the patient experienced a relapse, which was characterized by severe depressive symptoms. After discussing the treatment possibilities with her doctor, she agreed to receive rTMS rather than an antidepressant treatment, fearing that the medicine might affect the fetus. TMS was administered with a magnetic stimulator (magstim Rapid, Magstim Co. Ltd., UK) with a figure 8 coil (70 cm in diameter) known to produce a more focal magnetic field than any other coil shapes. Prior to the commencement of treatment, single-pulse TMS was used to measure resting motor threshold for the abductor pollicis brevis in the right hand using standard methods (Fitzgerald et al. 2002). In the first course of treatment, low frequency of rTMS was administered on the left side of the dorsolateral prefrontal cortex (DLPFC) with the handle held posteriorly and parallel to the floor, localized according to the previous reports 5 cm in front of the best spot for inducing motor-evoked potential size from APM muscle (Pascual-Leone et al. 1996). The parameters of rTMS were as follows: 1-Hz frequency, 90% motor threshold intensity, 20-s stimulation interval, and 1,200 pulse of stimulus in total. One session was applied per day. One course of treatment lasted two consecutive weeks, and no other medication was used during the treatment. Hamilton Rating Scales for Depression (HRSD; 24-item version) was used to evaluate the therapeutic effect. After the treatment, the HRSD score decreased from 35 to 12, and at the end of the first course of treatment, the patient was euthymic. However, 2 months later, the patient experienced a relapse again and required another course of rTMS treatment. Before the treatment, abdominal Doppler B scan showed that the fetus was normal, and the scores of HRSD and Hamilton Rating Scale for Anxiety (HRSA; 14-item version) for the patient were 18 and 24, respectively. During the second course of treatment, the rTMS was applied on both right DLPFC and the left DLPFC with the same parameters because of occurrence of the anxiety symptom. After 14 days of treatment, the score of HRSD and HRSA decreased to 8 and 7, respectively. However, two and a half months later, prior to delivery, the patient’s condition became unstable. She needed X. Zhang Jining Mental Hospital, Jining, Shandong Province, People’s Republic of China