Q: Does ocp causes constipation A: If by “OCP” you mean oral contraceptive pills, constipation is not a common side effect, but it can happen in some people. More common pill side effects are nausea, spotting, breast tenderness, headache, and mood changes. Constipation may be indirect, related to: - hormonal sensitivity especially progestin effects in some users, - reduced fluid/fiber intake, - less activity, - other meds iron, pain meds, antacids, etc.. If constipation started soon after beginning the pill and keeps happening, discuss with your clinician. They may switch pill type/formulation. Seek medical care sooner if you have red flags: - severe abdominal pain, - vomiting, - blood in stool, - weight loss, - no bowel movement for many days despite treatment.