The levonorgestrel intrauterine system in nulliparous women.

The levonorgestrel intrauterine system (LNG-IUS) has been used internationally for over 15 years by 7 million women. Concern about providing the LNG-IUS to nulliparous women still exists, despite growing evidence of its safety and efficacy in this population. Expulsion rates do not vary by parity and, although evidence in nulliparas is scant, perforation rates are low in all women. Efficacy of the LNG-IUS is excellent regardless of parity, with less than 1 pregnancy per 100 woman-years of use. Efficacy with immediate post-abortal insertion is also excellent and unvaried by parity. The presence of an LNG-IUS does not increase the risk of PID or infertility in either parous or nulliparous women and the LNG may be protective against infection. Acceptability is high in nulliparous women when compared either to parous LNG-IUS users or to nulliparous users of combined oral contraceptive pills. In conclusion, LNG-IUS is both safe and extremely efficacious for use in nulliparous women.