Pregnancy during the use of levonorgestrel intrauterine system.

Objectives: This study was undertaken to evaluate the pregnancy rate with the levonorgestrel intrauterine system (LNG IUS) and to analyze the outcome of pregnancies with the LNG IUS in situ in regular use.

Study Design: Questionnaires from 17,360 users of the LNG IUS were analyzed. With the consent of women reporting pregnancy during the use of the LNG IUS, related hospital records were reviewed concerning the pregnancies.

Results: Originally 132 pregnancies were reported. Medical records were reviewed from 108 of these women. In 64 pregnancies, conception occurred with the LNG IUS in situ. Thirty-three pregnancies were ectopic. The 5-year cumulative pregnancy rate per 100 users was 0.5 and the 5-year Pearl rate was 0.11.

Conclusion: Pregnancy with the LNG IUS in situ is rare. Ectopic pregnancies constitute 53% of all pregnancies. Typical pregnancy symptoms occur during pregnancies with the LNG IUS. The importance to counsel about the risk of pregnancy before insertion is emphasized.