If you are not pregnant then most likely cause for delay in your periods is the kidney infection
itself and not the CIPROFLOXACIN
as this medicine doesn't
commonly cause changes in your menstrual cycle.
Any woman can miss a period, spot or start early at any time or get delayed.Even if you have been regular till now,it doesn't prevent you from ever having an irregular cycle or two.
Just wait and watch.Once the infection is over,you shall be all right.
Failure to get back normal periods even after your UTI is over will necessitate a date with your gynecologist.