We appreciate the sensitive nature of this question. It can be challenging to navigate that staining that often occurs with
Mirena.
Since the fluid was not found
immediately after intercourse (i.e., some time had passed), it did not automatically render you
niddah. The usual laws of
stains (ketamim) apply.
Therefore, if the stain was smaller than a
gris (the size of a US dime or Israeli shekel), it may be disregarded. If it was larger than a
gris, and you did not transfer the stain to a white cloth to be
evaluated, you should assume that it did render you
niddah, since reddish/pinkish stains are generally a
niddah color.
(Please note that the halacha of blood found on the male member after relations is more stringent, even when not found immediately after intercourse. To head off potential future questions, it would be advisable for your husband to clean himself without looking, using a dark towel or disposable tissues.)
Please feel free to get back to us with any further questions.