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Change in period bleeding pattern could be due to hormonal, ovarian or uterine problems. The bleeding during and after intercourse could indicate possible cervical problems like erosion, pre-cancerous changes, cervical polyps etc.
Do not delay your visit to your gynecologist. Get examination, vaginal and PAP smear test, hormonal and blood work-up done. Further investigations (colposcopy, ultrasound scan, hysteroscopy etc) will be done if needed as directed by the initial investigation results.
Take care.