Sertraline-Associated Microscopic Colitis Flare in Pregnancy.

Microscopic colitis (MC) is a histologically confirmed cause of chronic diarrhea with normal endoscopy, and limited data complicate diagnosis and management during pregnancy. We report a 31-year-old woman with lymphocytic colitis, initially misdiagnosed as irritable bowel syndrome, who experienced an MC flare at 15 weeks' gestation after starting sertraline. Symptoms resolved with sertraline discontinuation and budesonide, with remission maintained postpartum. This case underscores the importance of medication review, early recognition, and multidisciplinary care in pregnant patients with persistent diarrhea, particularly when coordinating gastrointestinal and psychiatric management.