I know it is probably nothing to be worried about, but I am 18/19 weeks pregnant with my second child. Although I think I only started to feel the baby movements this week I also noticed that I have a very slight pinkish vaginal discharge. I went to the doctor 4 days ago and all seemed fine - even the urine test showed no infection. Should I be worried and contact my doctor or could it be just because of the increase in bloodflow?

I would contact your doctor. He is the one to diagnose you.

Any time you have unusual discharge you should contact your OB. If it's normal all it took was a phone call. Your OB would tell you that as well. Call them up. The nurse can even answer that one for you.