Pill and bleeding

Hi,

I had cgin last year while pregnant, had a llettz, and got clear margins. Had a repeat smear, endocervical, endometrial etc done in July this year. Results were clear. Was due back in jan. However I started the pill 28 days ago and never stopped bleeding. It was not heavy. I know this can be normal, but because of my history it has been recommended I have a review of my cervix. Has this happened to anybody else?