Levonorgestrel 13.5 mg IUD

The levonorgestrel 13.5 mg intrauterine device is the lowest-dose hormonal intrauterine device, with a small frame and a 3-year duration. It suits patients who want shorter-term, highly effective contraception with easier insertion and minimal hormonal exposure, accepting that bleeding suppression is modest.

Design and release. The frame measures 28 mm by 30 mm and the inserter tube is 3.8 mm in diameter. A silver ring near the top of the stem shows on ultrasound and X-ray. Release is about 14 micrograms daily at first and falls to about 5 micrograms daily by 3 years.

Mechanism. Cervical mucus thickening and local endometrial effects. Ovulation continues in most cycles.

Effectiveness. About 4 pregnancies per 1,000 women in the first year, and about 9 per 1,000 over 3 years.

Onset, duration and return to fertility. Immediate protection if inserted within 7 days of menses start. Duration 3 years. Fertility returns immediately on removal.

Bleeding profile. About 6 in 100 users are amenorrhoeic at 1 year and about 12 in 100 at 3 years.

Ideal candidates. Nulliparous patients, adolescents and patients planning pregnancy within about 3 years who want a hormonal device with a small inserter.

Not the device of choice. Heavy menstrual bleeding treatment, endometrial protection with oestrogen therapy, and patients who want amenorrhoea.

Examination and investigations. Bimanual and speculum examination; pregnancy exclusion; STI testing for those at increased risk.

Eligibility. The same categories as other levonorgestrel devices. Current breast cancer is category 4. Acute venous thromboembolism, decompensated cirrhosis, liver tumours and lupus with positive or unknown antiphospholipid antibodies are category 3. Breastfeeding within 48 hours of delivery is category 2.

Interactions. Enzyme-inducing medicines do not reduce effectiveness.

Counselling points. Most patients continue to bleed monthly; irregular spotting is common for 3 to 6 months. No STI or HIV protection. Plan replacement at 3 years.

Regimen line. Levonorgestrel 13.5 mg intrauterine device, releasing about 14 micrograms daily at first.

• Transcervical insertion through a 3.8 mm inserter.
• Start within 7 days of menses start with no backup, or at any other time if reasonably certain not pregnant with backup for 7 days.
• Insert within 48 hours or from 4 weeks postpartum, or immediately after abortion.
• Replace at 3 years; no missed-use rule.
• No adjustment for weight, kidney disease or enzyme inducers.
• Avoid initiation in severe liver disease and liver tumours.

Switching. From a hormonal method used correctly, insert at any time with no backup. From a copper device after day 7, advise condoms or abstinence for 7 days before the exchange and backup for 7 days after it.

Follow up. Review at 3 to 6 weeks. Book removal or replacement before 3 years; protection beyond 3 years is not assured.

Expected effects. Irregular light bleeding, acne, breast tenderness and headache, usually mild. Functional ovarian cysts are less frequent than with higher-dose devices.

Unscheduled bleeding. Exclude pregnancy, STI and malposition. Give mefenamic acid 500 mg orally three times daily for 5 days or ibuprofen 400 mg orally three times daily with food for 5 days (maximum 2.4 g daily).

Device complications. Expulsion, perforation (about 1 to 2 for every 1,000 insertions) and early infection.

Pregnancy. Rare; a high proportion are ectopic. Arrange urgent ultrasound.

Referral and escalation. Refer for suspected perforation, ectopic pregnancy or a device not located.