Can anyone tell me what this is or what is causing it? Do I need to call the doctor?

Devin

Not sure what this is or what is causing it. Should I be concerned? I am 16 weeks with twins and my next appointment isn’t until the 17th. There’s not much of a consistency to it. When I rub my finger across it, nothing comes off the liner. When I wipe, there isn’t anything on the toilet paper. Any help is greatly appreciated!!