Effect of Peripartum 40 Hz Audiovisual Stimulation on Postpartum Depression in Women Undergoing Elective Cesarean Section: A Randomized Clinical Trial

This is a single-center, prospective, randomized clinical trial evaluating whether short-term 40 Hz audiovisual stimulation during and after elective cesarean section can prevent postpartum depression. A total of 204 women (aged ≥18 years, singleton full-term pregnancy, ASA II-III) will be enrolled and randomized 1:1 to intervention or placebo control.

The intervention comprises three 30-minute sessions of combined 40 Hz flashing light and pulsed sound: initiated immediately after fetal delivery, then at 24 and 48 hours post-delivery. The control group receives identical-appearing non-flickering light and white noise. All participants receive standardized multimodal analgesia (epidural morphine 2.0 mg + regular acetaminophen) to minimize pain as a confounding variable.

The primary outcome is EPDS score at postpartum day 42. Secondary outcomes include EPDS at day 7, postpartum depression incidence (EPDS ≥ 10), ISI, and GAD-7 scores at days 1, 7, and 42. Sample size is 204 (102 per group), calculated for 80% power to detect a 2.0-point difference in EPDS (α=0.05, two-sided), accounting for 20% attrition.

Randomization uses block design with concealed allocation. Participants, outcome assessors, and data analysts are blinded. Analysis follows ITT principle, using ANCOVA for the primary outcome and linear mixed models for repeated measures. All participants provide written informed consent.

Inclusion criteria

• Women scheduled for elective cesarean section under combined spinal-epidural anesthesia;
• Age ≥ 18 years;
• Singleton, full-term pregnancy;
• American Society of Anesthesiologists (ASA) physical status II-III.

Exclusion criteria

• Refusal to sign informed consent;
• Prior or current diagnosis of psychiatric disorders, including major depressive disorder, bipolar disorder, schizophrenia, etc.;
• Preoperative Edinburgh Postnatal Depression Scale (EPDS) score ≥ 13 or presence of suicidal ideation;
• Current use of antidepressants, antipsychotics, or mood stabilizers;
• History of epilepsy or seizure-like episodes (any type);
• Presence of retinal disease, glaucoma, macular degeneration, cataract, or other ocular conditions that may affect light perception or cause abnormal sensitivity to light stimulation;
• Severe pregnancy complications: severe preeclampsia, HELLP syndrome, severe gestational diabetes mellitus with organ complications, significant placental abruption, or placenta previa with bleeding risk;
• Allergy to spinal anesthetics (ropivacaine, lidocaine, etc.);
• Participation in other interventional studies that may affect psychological status;
• Inability to receive light stimulation.