Could Birth Control Pills Cause Brown Discharge During Periods?

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I've been on birth control for a few weeks now (Ortho Tri-Cyclen Lo) and tomorrow is my last working pill before I go on the placebos. I started having brown discharge today, and I'm due for my period. I've had protected sex and just twice within the past two months, but I'm wondering if the brown discharge is normal for the first month of birth control. Thank you.