Im suffering from unilateral pulsatile tennitus for 2 months, im 20 weeks pregnant, i visited an ent he said my ear has no problem! what's the cause plz?

Tinnitis: Pulsatile tinnitus is ringing in the ears in tune with rhythm with the pulse of your heart. In a pregnant woman this is related to increased blood volume to carry a fetus. Increased blood flow through the base of the skull and the temporal bone leads to increase ringing in the ear in relation to your pulse. This is a natural byproduct of pregnancy.