Just to clarify a couple of things, in case others read this thread and are put off the IUD as a method of contraception:
The IUD (or the IUS, for that matter) is very definitely NOT a "recognised method for very early stage termination", and never has been.
2048- it's true that a copper IUD can be used as a form of emergency contraception, up to 5 days after unprotected sex, or up to day 19 of a 28 day cycle if unprotected sex occurred more than 5 days previously ie. it can (and is) used to prevent pregnancy where there has been a risk already in that cycle. Pregnancy is defined in law as starting at implantation, not at fertilisation.
At the risk of boring you with science: after fertilisation, it takes between 6 and 18 days for implantation to occur. This is where the 5 days/day 19 rule comes from - the IUD has to be in place before there is any chance of implantation, otherwise there would be a risk of it damaging an already-implanted pregnancy.
So if you have sex the night before an IUD fitting, even without a condom, as long as the IUD fit is successful, it will still prevent pregnancy. However, usually the advice is to use alternative contraception, or abstain, prior to the fitting in case the fitting is unsuccessful.
There are some people who have a moral objection to any method which prevents implantation but doesn't prevent fertilisation, which is fair enough, in which case they probably shouldn't choose the IUD/IUS.
Good luck RedSpringer!