Brown discharge at 18 weeks?

[Julietee]

I've been wearing white knickers today and noticed a brown staining building up throughout the day.

Nothing but whitish or yellowish when I wipe.
Could the yellow be drying brown?
I'm slightly worried it could indicate blood, but wouldn't it be present on the paper if so?

Could this be a thrush thing?

First off don't worry, weird discharge is all the rage during pregnancy! Best thing for it is to pop a sanitary towel in and give your midwife a call, then, gross as it sounds, save the used towel so she can have a look at it and put your mind at rest.