Please I will like to know if inserting a coil after three weeks of pregnancy can get rid of the baby

Define coil.

Please don't put any foreign objects up into your uterus. This could cause injury and infection in your uterus that could be fatal. Your uterus is a very welcoming place for bacteria so if you get any up there they'll grow. The result could be blood infections and possible death. If you damage the uterus than you'll start to bleed internally. It could also render you unable to carry a child to term but your body will try and either still birth the child or cause a uterine tear. There are so many health risks, don't do it.

If you need to abort a fetus than talk to your doctor, you might be able to take some drugs that will terminate the pregnancy or they'll be able to do a safe abortion. For your health, now and later on in life, talk to your doctor and get his help. Don't do this on your own.

As CravenMorhead said, if you are pregnant and wanting to end it, do not think about trying to do so yourself.

Or, if you are saying that you are 3 weeks pregnant, but had an IUD inserted and now want to know if it will cause you to have a miscarriage, it's possible, but women do sometimes become pregnant with an IUD in place, and the majority of the time it is simply removed without any problems and the pregnancy continues normally.

If you are asking, will the insertion of an IUD end a pregnancy that you are not wanting to continue with, then it's possible, but not guaranteed. Usually, IUDs are inserted during a period to avoid inserting it during a possible pregnancy. If you are already pregnant, you wouldn't have a period, and the doctor should do a pregnancy test. Obviously if you are shown to be pregnant, then they won't insert it.

Please clarify with some more information what your situation is.