This is an updated guideline from the FSRH. There isn’t really anything very new in this, so I’ve just summarised some of the things I wasn’t aware of or was a bit hazy on. I have further updated this blog in Mar 21 to reflect the new LNG-IUS coils available.
Method of action
Copper intrauterine devices (Cu-IUD) provide a hostile environment to fertilisation, have a cervical mucous effect and an anti-implantation effect.
Levonorgestrel Intrauterine Systems (LNG-IUS) like Mirena have an uncertain method of action. They seem to work through cervical mucous changes and by effects on the endometrium. Some women stop ovulating with an LNG-IUS. There may be a ‘foreign body effect’ too.
All women should be screened for their risk of STIs. Women who are at risk should be tested. As a minimum this should include Chlamydia testing. If women are symptomatic for infection, this should be treated before an IUC (intrauterine contraception) is fitted. If women are asymptomatic, then the IUC can be fitted before the results are received, as long as the woman can easily be contacted