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How can a small piece of copper prevent you from getting pregnant?

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Birth control comes in all shapes and sizes, from the incredibly high-tech to the ridiculously simple. So if you're worried about the long-term effects of taking hormones, or tired of taking a daily birth-control pill, there's always another method of birth control that's simple, cheap and effective: the Copper T. The only downside? It requires a doctor to implant it for you.

The Copper T has been in use for over five decades, touting a greater than 99% pregnancy prevention rate. What is the process behind inserting a Copper T, and how exactly can it prevent a pregnancy?

What is a Copper T?
The Copper T is a simple intra-uterine device (IUD) made of a flexible, "T" shaped piece of plastic wrapped with a thin copper containing wire. This shape is chosen as it fits the area around the uterus, allowing for the Copper T to sit in place for years without moving around.


When inserted, the ends of the "T" are folded and inserted into the patient with a straw-like tube. Once in place, the spermicidal effects of the Copper T are in effect, and the the tiny piece of plastic and copper becomes a birth control device.


How does it work?
Copper ions destroy biochemical structures with ease — they confound enzyme structures, making them useless. The ions can also bore holes into cell membranes, by interacting with the cells lipid bilayer, spilling the contents of the cell into the surrounding environment.

Once a Copper T is in place, copper ions separate from the coiled copper wire and begin to alter the biochemistry around the uterus. "Alter" sounds like a strong and permanent word, but it really isn't. The copper ions leach into uterine fluids and the cervical mucus — when these fluids come in contact with sperm, the copper ions sound the death knell for the squiggly beasts.

Copper ions prevent pregnancy by inhibiting the movement of sperm, because the copper-ion-containing fluids are directly toxic to sperm. Even if an aggressive little spermatozoa fertilizes an egg, the copper ion laden environment prevents implantation of the fertilized egg, and thus pregnancy.

Low maintenance
Once implanted in a simple outpatient procedure, a Copper T can work successfully as a form of birth control for over a decade. The long lasting effects make this IUD an exceptionally inexpensive method, which doesn't require taking a pill or putting on a condom.


The only maintenance necessary is a monthly check to see if the piece of thin thread used to track the position of the IUD is in place around the cervix. This piece of plastic thread is used by a physician to remove the IUD and reverse the procedure, allowing a woman to become pregnant within weeks after removal.


Emergency contraception and STDS
The Copper T presents another interesting application. The device can be used as a form of emergency contraception if implanted up to five days after ovulation.

The emergency contraceptive application is due to the timetable necessary to implant a fertilized egg, which can happen anywhere from six to twelve days after ovulation. This is more than enough time for the copper ions released to prevent implantation.


Copper IUDs do not prevent against sexually transmitted diseases, however, and they open the user up to a variety of pelvic infections if an STD/STI arises. These infections are very serious and require immediate treatment — with infertility one possible effect, if the pelvic inflammation goes untreated.

Top image: Lukiyanova Natalia / frenta/ Additional images from Grace Herbert/Flickr and The Contraceptive CHOICE Project/PD. Sources linked within the article.