Reading Dr Lloyd's letter1 in the July 2013 issue of the Journal has prompted me to write in on this topic.

Removal of an intrauterine device (IUD) involves traction on the threads causing the horizontal arms of the device to come together in the narrower lower half of the uterus during its downward movement.

It is relatively easy for the collar of hormone in an intrauterine system (IUS) to be dislodged. The combined diameter of the folded arms is marginally greater than the vertical limb of the device. Shearing could cause the hormonal collar to slip upwards on downward traction of the device during removal.

This is different to a copper IUD where there is a difference in the diameters of the vertical limb and the folded horizontal arms of the device.

Neither collar, copper nor hormone, should be retained in the uterus if conception is being considered by the woman. However, it is also important to remove them to exclude the small possibility of actinomyces infection.