Risk of Perforation: 1 to 2 per 1000 insertions

Risk of Perforation in women who are breastfeeding: 6 per 1000 insertions

Risk of Expulsion: 1 in 20

Following an IUC insertion, women are advised to feel for the threads at their cervix. If they are unable to feel the threads, they are advised to have a speculum examination to have the threads visualised.

Non-visible threads

IUC threads may not be visible in the vagina as a consequence of IUD expulsion, perforation or pregnancy, but often the cause is retraction of the threads into the cervical canal or uterus. If no threads are visible on speculum examination, pregnancy should be excluded, additional precautions advised, and an ultrasound scan undertaken to locate the device.

Although some uterine perforations are identified at the time of insertion, there can be a delay before perforation is identified. For those women in whom perforation is identified at the time of insertion, the procedure should be stopped, the IUC removed, and vital signs (blood pressure and pulse rate) and level of discomfort monitored until stable.

Mild lower abdominal pain, ‘lost threads’, changes in bleeding (LNG-IUS) and a history of pain at the time of insertion may indicate uterine perforation. The threads may remain in the vagina and may break off at attempted removal if an IUC has become embedded in the uterine wall or has perforated the cervix.

If there is any possibility of perforation at the time of insertion or later, an ultrasound scan should be arranged as soon as possible in order to locate the device. Women should be advised to use additional contraceptive precautions in the interim.

FSRH Clinical Guideline: Intrauterine Contraception (April 2015, amended September 2019) - Faculty of Sexual and Reproductive Healthcare

Acute Referral to Gynaecology:

Symptoms and signs of bowel perforation (peritonitis)

Symptoms and signs of vessel perforation (collapse)

Ongoing severe or worsening pelvic pain