Most women can use an IUS, including women who have never been pregnant and those who are HIV positive. Your GP or clinician will ask about your medical history to check if an IUS is the most suitable form of contraception for you.

Your family and medical history will determine whether or not you can use an IUS. For example, this method of contraception may be unsuitable if you think you may already be pregnant or if you have:

• breast cancer (or have had it) in the last five years
• cervical cancer
• liver disease
• unexplained vaginal bleeding between periods or after sex
• arterial disease or history of serious heart disease or stroke
• thrombosis (blood clots) in any vein or artery
• an untreated sexually transmitted infection (STI) or pelvic infection
• problems with your uterus or cervix

Like the IUD, IUS can be unsuitable for women who have untreated STIs. A doctor will usually perform an internal examination to make sure you don't have any existing infections.

Using an IUS after giving birth

An IUS can usually be fitted four to six weeks after giving birth (vaginal or caesarean). You'll need to use alternative contraception from three weeks (21 days) after the birth until the IUS is put in. In some cases, an IUS can be fitted within 48 hours of giving birth.

It is safe to use an IUS when you're breastfeeding and it won't affect your milk supply.

Using an IUS after a miscarriage or abortion

An IUS can be fitted by an experienced doctor or nurse straight after an abortion or miscarriage, as long as you were pregnant for less than 24 weeks. If you were pregnant for more than 24 weeks, you may have to wait a few weeks before an IUS can be fitted.