This randomized, sham-controlled mechanistic trial will examine whether a single session of high-frequency repetitive transcranial magnetic stimulation, rTMS, applied to the left dorsolateral prefrontal cortex can modify heart-brain coupling in women with recurrent pregnancy loss and elevated body mass index, BMI. Women with recurrent pregnancy loss often experience reproductive, metabolic, and emotional stress at the same time, and this combined vulnerability may be associated with altered autonomic regulation and exaggerated cardiac responses to stress. The left dorsolateral prefrontal cortex is a key brain region involved in cognitive control, emotion regulation, and top-down modulation of autonomic function.
Eligible participants will be randomly assigned in a 1:1 ratio to receive either real or sham rTMS at the same left dorsolateral prefrontal target. The stimulation protocol will use 10 Hz rTMS at 100% motor threshold, delivered in 30 cycles of 5 s stimulation followed by 11 s inter-train interval, with simultaneous 3-lead electrocardiography recording. The primary endpoint will be the between-group difference in mean heart-brain coupling across 30 stimulation cycles. Safety and tolerability will also be monitored. This study is intended to provide mechanistic evidence and methodological support for future multi-session randomized trials in this population.
1.Female participants aged 18-45 years and right-handed.
2.Fulfillment of the prespecified definition of recurrent pregnancy loss in this study, defined as at least two consecutive spontaneous miscarriages occurring before 28 weeks of gestation.
3.BMI ≥24 kg/m², classified as overweight or obesity according to the Chinese adult criteria for overweight and obesity.
4.Currently not pregnant and in a clinically stable condition. If there is a recent history of missed abortion, appropriate management must have been completed and obstetric assessment must confirm the absence of acute vaginal bleeding, infection, marked abdominal pain, or hemodynamic instability.
1.Presence of contraindications to transcranial magnetic stimulation or elevated seizure risk, including but not limited to epilepsy or a history of unexplained seizures, intracranial ferromagnetic metal implantation, or the presence of electronic or metallic implanted devices within 30 cm of the coil that are judged unsuitable for transcranial magnetic stimulation.
2.Current pregnancy.
3.Hemodynamic instability or cardiovascular abnormalities that may substantially affect interpretation of the primary endpoint, including systolic blood pressure >180 mmHg or <90 mmHg, atrial fibrillation or other clinically significant arrhythmias, valvular heart disease, marked sinus bradycardia, symptomatic coronary artery disease, or other cardiovascular conditions judged by the research team to make participation unsuitable.
4.Uncontrolled major medical or neurologic disorders, particularly those that may substantially affect autonomic state, ECG recording, or interpretation of the primary endpoint, including uncontrolled thyroid dysfunction, uncontrolled diabetes mellitus, significant cerebrovascular disease, neurologic disorders, or active pulmonary disease.