Brown to pink discharge at 30 weeks

2 days na po ako may discharge, pero minsan minsan lang. Wala ung ob ko kahapon pero in-advised ako na magpa ultra, okay naman sa ultra, cervix closed and everything is normal. May naka-experience na po ba neto? I’m going to my OB tomo, for urinalysis po ako to detect if may infection. May naka-experience po ba neto? Thank you!