Home-Based Transcranial Direct Current Stimulation for Menstrual Pain and Premenstrual Symptoms: A Randomized Controlled Trial

Tatiana CLA Silva,1 Yvinna T Rodrigues,1 Emilė Radytė,2 Ervinas Bernatavičius,2 Alexander A Cook,2 Ieva Karvelyte,2 Maria LAS Carvalho,1 Luiza Macedo,1 Joyce Maria Pereira de Oliveira,1 Talita Duarte Martins,1 Maria Fonseca,1 Jeysse AB Nascimento,1 Rodrigo Pegado,1 Maria TABC Micussi1 1Department of Physical Therapy, Federal University of Rio Grande do Norte, Natal, Rio Grande do Norte, Brazil; 2Samphire Neuroscience Ltd, London, UKCorrespondence: Maria TABC Micussi, Department of Physical Therapy, Federal University of Rio Grande do Norte, Av. Senador Salgado Filho s/n, Lagoa Nova, Natal, Rio Grande do Norte, 59078-970, Brazil, Email thereza.micussi@ufrn.brBackground: Primary dysmenorrhea (PD) and premenstrual syndrome (PMS) are common gynecological conditions that impair quality of life and productivity. Current treatments are mostly pharmacological and often come with side effects. Transcranial direct current stimulation (tDCS) has emerged as a promising non-invasive neuromodulation technique for pain and mood symptoms.Methods: We conducted a double-blind, randomized, sham-controlled clinical trial to evaluate the effects of home-based, self-administered dual-target tDCS on menstrual pain, mood symptoms, functional capacity, and quality of life in women with PD and PMS. Forty participants were randomized to receive either active or sham tDCS over five days in a menstrual cycle. Primary and secondary outcomes were assessed at baseline, post-intervention, and one-cycle follow-up.Results: No significant group-by-time interaction was found for menstrual pain (VAS) (F(2,64)=1.09, p=0.34). Menstrual pain decreased over time in both groups (F(2,64)=7.93, p< 0.001). At follow-up (T2), mean VAS was 23.44 ± 29.31 in the active group vs 39.43 ± 31.10 in the sham group (Cohen’s d = − 0.53; 95% CI − 37.2;5.2). Exploratory analyses suggested improvements in negative mood (Estimate = 3.50, SE = 1.41; 95% CI 0.74– 6.26) and psychological quality of life (Estimate = 0.36, SE = 0.15; 95% CI 0.07– 0.65). No serious adverse events were reported, and most adverse effects were mild.Conclusion: Home-based self-administered tDCS may be a safe and potentially beneficial non-pharmacological approach for managing menstrual pain and emotional symptoms in women with PD and PMS. Larger trials with longer follow-up periods are warranted to confirm these preliminary findings and to better understand possible longer-term effects.Keywords: transcranial direct current stimulation, neuromodulation, menstrual pain, home-based therapy