Is this true ?

I heard that some discharge can be an early sign of pregnancy? Is this true ?

If so what kind ?

I am having discharge which is unusual especially if my period is suppose to come soon.

I do spot when I’m about to begin my period but this time I’m having more of a yellow/ clear discharge with. Some time slot of red or light pink mixed into it.

I did letrozole this month( I have irregular cycle-PCOS)

Negative pregnancy test. Last time I got my period was June 16.