A 30-year old woman with family history of hearing loss from her mother's side developed hearing problem during pregnancy. Hearing loss is bilateral, slowly progressive, with bilateral tinnitus that bothers her at night. Pure tone audiometry shows conductive hearing loss with an apparent bone conduction hearing loss at 2000 Hz. What is the most likely diagnosis?

Otosclerosis is characterized by abnormal removal of mature dense otic capsule bone by osteoclasts, and replacement with the woven bone of greater thickness, cellularity, and vascularity. When disease involves the annular ligament of the oval window and stapes footplate, a conductive hearing loss (CHL) occurs which is slowly progressive, usually bilateral and asymmetric. The hallmark of bone conduction thresholds in otosclerosis is the Carha notch which is as a result from the disruption of normal ossicular resonance, approximately at 2000 Hz. One of the earliest signs of otosclerosis is an abnormal acoustic reflex. Hormonal influences during pregnancy might cause a more rapid progression in women, bringing them to clinical attention.