Higher dose levonorgestrel-releasing intrauterine systems lowers risk of ectopic pregnancy

The incidence rate of ectopic pregnancy during usage per 100 woman-years was calculated using the time of intrauterine device (IUD) installation prior to ectopic pregnancy and the quantity of LNG-IUS marketed throughout the research period (Pearl Index).

The key findings of this study were as follow:

1. There were 105 women with an ectopic pregnancy diagnosis who had a known kind of hormonal IUD in place; 94 of these women were taken into account in the Pearl Index calculations.

2. For the LNG-IUS 13.5-mg, the estimated Pearl Index for ectopic pregnancy was 0.136; for the LNG-IUS 19.5-mg, 0.037; and for the LNG-IUS 52-mg, 0.009.

3. The relative risk (RR) for ectopic pregnancy was greater for LNG 13.5 mg during the first year and for both 13.5 mg and 19.5 mg during the whole trial period, using the 52 mg LNG-IUS as the referent.

In conclusion, the findings indicate that the likelihood of an ectopic pregnancy increases with decreasing IUD dosage. When giving contraceptive advice to a woman with established risk factors for ectopic pregnancy who is thinking about a hormonal IUD, higher-dose LNG-IUS should be taken into account.

Reference:

Elgemark, K., Graner, S., McTaggart, J., Ramirez Löfström, J., Sörensen, D., Envall, N., & Kopp Kallner, H. (2022). The 13.5-mg, 19.5-mg, and 52-mg Levonorgestrel-Releasing Intrauterine Systems and Risk of Ectopic Pregnancy. In Obstetrics & Gynecology (Vol. 140, Issue 2, pp. 227–233). Ovid Technologies (Wolters Kluwer Health). https://doi.org/10.1097/aog.0000000000004846