Two low-dose levonorgestrel intrauterine contraceptive systems: a randomized controlled trial

Area of Science:

• Reproductive Health
• Contraception
• Gynecology

Background:

• Levonorgestrel intrauterine systems (LNG-IUS) are utilized for contraception.
• Evaluating lower-dose formulations of LNG-IUS is crucial for expanding contraceptive options.

Purpose of the Study:

• To assess the efficacy and safety of two distinct low-dose levonorgestrel intrauterine contraceptive systems.
• To compare pregnancy rates and adverse events between a 13.5 mg and a 19.5 mg LNG-IUS over three years.

Main Methods:

• A randomized controlled trial involving nulliparous and parous women aged 18-35 years.
• Participants were assigned to either a 13.5 mg or 19.5 mg LNG-IUS for three years.
• The primary efficacy endpoint was the pregnancy rate, calculated using the Pearl Index.

Main Results:

• Pregnancy rates were low and comparable between systems: 0.33 per 100 women-years for 13.5 mg and 0.31 for 19.5 mg.
• Partial expulsions occurred in 4.56% (13.5 mg) and 3.58% (19.5 mg) of users.
• Discontinuation due to adverse events was reported in 21.9% (13.5 mg) and 19.1% (19.5 mg) of participants.

Conclusions:

• Both low-dose levonorgestrel intrauterine contraceptive systems are highly effective for three years.
• These systems are generally well-tolerated, offering a safe contraceptive choice.