[underthesun]

If life begins at conception, use of an IUD is abortion.

This is only true if conception actually takes place. There are 2 types of IUDs, one is copper and the other progesterone releasing both of these act as spermicides, so IUDs while they do prevent implatation will also prevent conception.

[SoothingDave]

There are 2 types of IUDs, one is copper and the other progesterone releasing both of these act as spermicides, so IUDs while they do prevent implatation will also prevent conception.

How does the IUD owner/user know which method was used to prevent a pregnancy?

SD

[lugsoul]

Neither acts as a spermicide. They may act as a physical barrier to conception, though most docs are unclear on the extent to which this occurs. Progesterone is most definitely not a spermicide. The negative effect of progesterone is to thicken the cervical mucus and slow the mobility of sperm.

The primary effect of IUDs is to prevent implantation.