A lady has B/L hearing loss since 4 years which worsened during pregnancy. Type of impedence auditometry graph will be :

**Core Concept**
Middle ear dysfunction, particularly otosclerosis, can affect tympanic membrane mobility and middle ear function, leading to conductive hearing loss. During pregnancy, changes in blood volume, venous pressure, and fluid shifts can exacerbate middle ear problems.

**Why the Correct Answer is Right**
In otosclerosis, the stapes bone is fixed due to abnormal bone growth, leading to reduced mobility of the ossicular chain. Impedance audiometry measures middle ear function by assessing the movement of the tympanic membrane and ossicles. A type B tympanogram, characterized by a flat peak or no peak at all, indicates a non-compliant tympanic membrane and immobile ossicles, which is typical in otosclerosis.

**Why Each Wrong Option is Incorrect**
* **Option A:** A type A tympanogram represents a normal, compliant tympanic membrane, which is not consistent with otosclerosis.
* **Option B:** A type C tympanogram shows a high compliance, often seen in Eustachian tube dysfunction, which is not the primary issue in this case.
* **Option D:** A type Ad tympanogram indicates a middle ear fluid, which can cause conductive hearing loss, but the pattern is different from what is expected in otosclerosis.

**Clinical Pearl / High-Yield Fact**
Otosclerosis is a leading cause of conductive hearing loss in young adults, particularly women, and is associated with a higher risk of developing sensorineural hearing loss over time.

**Correct Answer: C. Type B tympanogram.**