Sleep to Reduce Incident Depression Effectively in Peripartum

This study is testing whether treating insomnia during pregnancy using an online Cognitive Behavioral Therapy for Insomnia (CBT-I) program can prevent the development of postpartum depression. Insomnia is known to be a strong risk factor for depression, and this study aims to break that link during the peripartum period. **You may be eligible if...** - You have a single (not multiple) pregnancy and are between 14 and 31 weeks along - You have been diagnosed with insomnia disorder lasting at least 1 month - Your insomnia severity score is 11 or higher - You do not currently have major depression (Edinburgh score below 13 at screening) - You are 18 years or older - You have reliable internet access - You are not currently in therapy for insomnia or major depression **You may NOT be eligible if...** - You have a high-risk pregnancy (such as pre-eclampsia or placenta previa with bleeding) - You have active suicidal thoughts - You work night or rotating shifts, or plan to travel across 3+ time zones in the 2 months after baseline - You have untreated restless legs syndrome - Your daytime sleepiness score is very high (Epworth Sleepiness Scale above 15) - You have a sleep or mental disorder that would make sleep restriction unsafe (such as narcolepsy, bipolar disorder, or epilepsy) Talk to your doctor to see if this trial is right for you.