Brown tissue in urine 6 week and 2 days

Angela • PCOS. Male factor infertility after cancer. Pregnant with first after 1st Fresh IVF round. Due 27th Oct 19. *3 lovely step children*

Hi ladies, sorry for the TMI but was a bit worried. The other day I saw a bit of small tissue in my urine which was a browny-red colour and today I have noticed the same thing but more brown. They are only small bits and haven't noticed anything when I wipe or in my undies. Has anyone else had this before and is it anything to worry about? I haven't had any pain. Please help xxx