Health Risks, Side effects

Breast cancer

There may be an association between current or recent hormonal contraception use (including LNG-IUDs) and breast cancer; however, any increased risk appears to be small.

Ovarian cysts

Ovarian cyst incidence is elevated during LNG-IUD use with 80%–90% resolving spontaneously within 3 months. The vast majority are asymptomatic. Ovarian cysts can cause pelvic pain, dyspareunia and rare serious adverse events e.g. cyst rupture. LNG-IUD discontinuation rates due to ovarian cysts are about 0.5% across the lifetime of the various LNG-IUDs.

Bone mineral density

Current evidence suggests there is no significant effect on serum estradiol levels or bone mineral density (BMD) in LNG-IUD users.

Bleeding

Inform potential LNG-IUD users about possible bleeding pattern changes, to inform decision-making and improve satisfaction rates.

Prolonged, frequent and irregular bleeding and number of bleeding/spotting days generally reduce over the first year of LNG-IUD use and rates of amenorrhoea and infrequent bleeding increase. By the end of licensed duration of use, amenorrhoea is 11%–12% of 13.5 mg users, 23% of 19.5 mg users and 42% of 52 mg users.

LNG-IUD replacement appears to induce a small, temporary increase in bleeding/spotting in the first 90 days after the procedure. Bleeding/spotting then returns to a very low and constant level, with higher rates of amenorrhoea than in first-time users at 4-6 weeks post-insertion.

Discontinuation due to bleeding is low across the 13.5 mg, 19.5 mg and 52 mg devices at ≤ 5% over 3–5 years.

Other Side effects

Acne, breast tenderness, headache and mood changes are reported. Evidence is too limited to confirm or exclude a causative effect. These symptoms are more prevalent in the first few months after insertion but decrease with time.

In the general population there are no significant differences in weight gain when LNG-IUDs are compared with Cu-IUDs and no evidence to support a causal association between IUC use and weight gain.