A Study of Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) for Insomnia During Pregnancy

Brief Summary

The goal of this clinical trial is to learn whether transcutaneous auricular vagus nerve stimulation (taVNS) can treat insomnia during pregnancy. It will also learn about the safety of taVNS for pregnant women and their fetuses. The main questions it aims to answer include: Can taVNS improve sleep quality in patients with gestational insomnia, as measured primarily by the Insomnia Severity Index (ISI)? Compared with a 2-week delayed intervention, can starting taVNS intervention 2 weeks earlier lead to superior improvements in sleep and mood outcomes? Does taVNS have any adverse effects on maternal electrocardiogram, fetal ultrasound, or fetal heart rate? What medical problems (adverse events) do participants experience when receiving taVNS treatment? Researchers will compare active taVNS with sham stimulation (the device looks and operates the same but delivers no effective current), while also incorporating a delayed-intervention group (no intervention during the first 2 weeks) as a temporal control, to observe whether taVNS can treat gestational insomnia and whether earlier intervention offers additional advantages. Participants will: Receive active taVNS or sham stimulation according to their randomized group assignment during specified time periods, at a frequency of 2-3 times daily, 30 minutes per session, for 14 consecutive days (the early-intervention group begins immediately upon enrollment; the late-intervention group has a 2-week waiting period after enrollment before starting intervention; the early-intervention group undergoes crossover at Day 15). Complete a 3-day pre-trial period after enrollment for device operation training and individualized stimulation intensity setting. Attend hospital follow-up visits at baseline (Day 0), Day 15, and Day 30 to complete sleep assessments (ISI, AIS, PSQI, ESS) and mood assessments (HAMA, HAMD). Undergo repeated maternal electrocardiogram, fetal ultrasound, and fetal heart rate monitoring before and after treatment to evaluate safety. Maintain a daily treatment diary (recording usage time, frequency, and any adverse symptoms), with device-internal usage logs cross-checked against diaries to ensure adherence.