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How does the Paragard IUD work?

Medically reviewed by Carmen Fookes, BPharm. Last updated on Sep 5, 2022.

Official answer


Paragard is a small T-shaped intrauterine contraceptive device that works by continuously releasing a small number of copper ions into the uterine cavity which prevents pregnancy. These copper ions change the fluid within the fallopian tube and the uterus, disrupting the motility of sperm and making them unable to fertilize an egg. Paragard may also prevent the implantation of a fertilized egg.

What is Paragard?

Paragard is a small T-shaped intrauterine device (also called an IUD) made of soft, flexible plastic that is inserted into a woman’s uterus to prevent pregnancy. The vertical bar of the device is wrapped in thin copper wire and each horizontal bar of the T has a copper collar. Once in place, Paragard starts working immediately.

Copper is a mineral that occurs naturally in food and our environment. It has been FDA approved for over 30 years and found to be safe and effective. Copper also has antimicrobial properties and will help protect against bacteria and viruses.

Paragard weighs less than 1gm and measures 32mm (1 17/64th inch) horizontally, 36mm (1 27/64th inch) vertically, and has a 3mm (1/8th inch) diameter bulb at the top of the vertical stem. A very thin thread is tied through the tip, which results in two white threads hanging down, which make detection and removal of the device easier. The T-frame of the device contains barium sulfate which enables it to be seen under x-ray. Paragard contains no latex.

Paragard belongs to the class of devices called intrauterine copper contraceptives.


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