How Does the Copper IUD Work?

The IUD (IntraUterine Device) is pretty cool — a small T-shaped device that’s inserted (by your doc) into the uterus. The copper IUD has copper wiring and collars around the T-shaped frame and it does not contain any hormones.

It works by affecting the motility and viability in sperm i.e. it creates an inhospitable environment for the sperm. Plus, there’s a local inflammatory response that’s also created in the uterus.

T shape with magenta coil around the vertical part of the T. The words "copper IUD" are beside it in green.

Since it doesn’t contain any hormones and it works locally, it doesn’t actually affect your ovulation or production of hormones like the pill does or like the hormonal IUD can in some situations. So, you can still reap the rewards of naturally cycling hormones while you have the benefit of non-hormonal contraception.

But, it can cause heavier bleeding and more discomfort/pain for many people especially in the first 3-6 months of being inserted which unfortunately (and understandably) is a big reason people ditch the copper IUD soon after insertion.


– Effective as a contraceptive

– Non-hormonal and does not interfere with ovulation

– 10-year shelf-life, so it’s no fuss (apart from insertion at the doctor’s office)

– Effective as emergency contraception


– Doesn’t protect against STIs

– May cause heavy bleeding especially in the first 3-6 months

– It can be painful/uncomfortable to insert and may lead do some uterine cramping in the first few weeks after insertion

– It releases a bit of copper locally which hasn’t shown to be problematic, but it is not suitable for those with a copper allergy

– It can come out (slim chance which is more likely soon after insertion, especially if inserted post-partum) and there is a small risk of uterine perforation