The actual removal of the IUD will not make you niddah. However, the hormonal changes caused by the removal may cause withdrawal bleeding. We therefore suggest you check for staining before having intercourse, for a week or so, to be sure you are not niddah. We recommend checking by wiping externally with toilet paper, not immediately after urinating. If you find a stain you should refrain from intercourse (as blood found immediately after relations, or on the husband’s body, would be problematic). However, the staining on the toilet paper will not make you niddah.
If you would like to avoid becoming niddah from possible staining, you should wear colored underwear and wait at least a few seconds (ideally, about 15 seconds) after urinating before wiping. If you suspect you are staining, but not enough to necessarily consider yourself niddah, you should avoid having relations for about 24 hours from finding a stain, and check as described above prior to having relations.
If you want to become niddah on purpose, you could rely on those opinions that are more stringent about IUD removal and consider yourself niddah from the time of removal, or you could perform an internal bedikah at a time you suspect you are staining.
Please remember that if you are not using other forms of birth control, you could become pregnant before your first period. However, you can reduce the chances by waiting until you ovulate and an additional two days before having relations. For more information please read our article on the Fertility Awareness Method.
This response has been updated to reflect the rulings of our current Rabbinic Supervisor, Rav Kenneth Auman, regarding waiting before wiping.