Last week, I noticed that my colleague had a blood stain on her backside. It was very obvious that her period had either started unexpectedly or she had leaked through protection. This was not what I would categorise as a small stain. As soon as I realised that she was unaware and was going to keep walking around like that, I simply told her that she has a stain. I did not even utter the words blood or period. Ever since, she has been trying to avoid me as much as she can, and I can tell she's upset that I said it in front of our other colleagues. Because we're nurses, I really did not think it was a big deal. We all have an understanding of the human body and its functions. She is considerably younger so that may be it. I have considered apologising but do not want to make the work atmosphere more tense. Was I wrong to say anything?