IUD insertion in clean days

Whether IUD insertion itself renders a woman niddah is subject to halachic debate.  Our site's position is that IUD insertion itself is generally carried out with a very small instrument and does not render a woman niddah.  The question that remains is whether any bleeding that results (over the next few days) can be ascribed to trauma from the insertion, in which case it would not render a woman niddah or invalidate her clean days.

Our site's rabbinic supervisor, R Yehuda Henkin rules that bleeding following insertion does render a woman niddah, unless she can establish medically that the blood is from uterine trauma.  To establish this medically, either the doctor would have to say he caused uterine trauma consistent with the bleeding, or such trauma would have to be visible on inspection.  Ideally, at insertion, a woman should ask her physician if he caused trauma or sees bleeding from the insertion.  

Thus, depending on your local rabbi's ruling on this issue, you may have to make a new hefsek taharah and count a new seven days.  That would be Rav Henkin's ruling, barring any additional medical information, as above.