How the non-hormonal coil (IUD) works

This coil does not release any hormones, so the natural hormones of your menstrual cycle will continue.

The non-hormonal coil works locally, just in the womb (uterus) by creating a very mild inflammatory reaction. This is enough to stop both sperm and egg from surviving and to prevent eggs from implanting.

When will it stop you getting pregnant? 

The non-hormonal coil will start to prevent pregnancy as soon as it’s inserted.

Types of non-hormonal coil

Different types of coil use slightly different methods to keep small amounts of copper in the uterus.

The T-shaped coil

The most common non-hormonal coil is a T-shaped plastic frame wrapped with copper wire:

  • the T-shaped frame is designed to fit within the triangular shape of the womb (the arms of the T fold down so they can pass through the neck of the womb)

  • the size of the device shows how much copper is on it and how long it will last, but it will be between 5 and 10 years depending on the design. For a 10-year coil, the copper is on the arms and the stem of the T-shape. With the 5-year coil the copper is often only on the stem of the T

The frameless coil

A new style of IUD is a ‘frameless device’, which consists of copper beads on a soft wire. These are also called the intrauterine ball or IUB. These are not currently available in the UK.

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