What is the comparison between Levonorgestrel (a progestin) and Norethindrone (a progestin) for contraceptive use in adolescents?

From the Guidelines

Levonorgestrel is generally preferred over norethindrone for contraceptive use in adolescents due to its better side effect profile and efficacy, as evident from the studies published in Pediatrics 1. When comparing levonorgestrel and norethindrone for contraceptive use in adolescents, several factors come into play.

• Levonorgestrel is typically dosed at 0.15 mg daily in combined oral contraceptives or 1.5 mg as a single dose for emergency contraception, while norethindrone is usually prescribed at 0.35 mg daily for mini-pills or 5-10 mg daily for menstrual disorders.
• Levonorgestrel tends to cause fewer androgenic side effects, such as acne and hirsutism, compared to norethindrone, making it more suitable for adolescents concerned about these issues 1.
• Levonorgestrel also has higher progestational activity at lower doses, allowing for more effective contraception and menstrual regulation with fewer metabolic effects.
• However, norethindrone may be preferred in specific situations where its unique properties are beneficial, such as when treating endometriosis or when estrogen-containing options are contraindicated.
• Both medications require counseling about potential side effects, including irregular bleeding, headaches, and mood changes, especially during the first few months of use, as highlighted in the studies 1.
• Regular follow-up appointments are important to monitor tolerance and address any concerns, ensuring the best possible outcome in terms of morbidity, mortality, and quality of life for the adolescent patients.

From the Research

Comparison of Levonorgestrel and Norethindrone for Contraceptive Use in Adolescents

• The efficacy and acceptability of levonorgestrel and norethindrone as contraceptive options for adolescents have been compared in several studies 2, 3.
• A study published in 2009 compared the performance of a combined injectable contraceptive containing norethisterone enanthate and estradiol valerate with a combined oral contraceptive containing levonorgestrel and ethinyl estradiol in adolescents, and found that the injectable contraceptive had significant differences in baseline social risk, confidence, psychiatric problems, consumption of alcohol, and number of sexual partners 2.
• Another study published in 1992 found that there was no significant difference in compliance or pill satisfaction between a levonorgestrel-containing triphasic pill and a monophasic norethindrone-containing pill in adolescent patients, but that socioeconomic factors were the overriding predictors of compliance 3.
• The use of levonorgestrel implants has also been studied in adolescents, with one study published in 1995 finding that levonorgestrel implants provided superior protection against unintended pregnancy, but caused more side effects than oral contraceptives in the early months after initiation 4.
• A study published in 1994 found that the levonorgestrel implant was a highly effective and desirable form of contraception for adolescents, with timely and reassuring counseling from nurse practitioners effective in allaying fears and dissatisfaction 5.

Side Effects and Satisfaction

• The studies found that levonorgestrel and norethindrone had different side effect profiles, with levonorgestrel implants causing more menstrual irregularity and cramping, amenorrhea, nervousness, abnormal hair growth or loss, rashes, and an increase in appetite than oral contraceptives 4.
• However, another study found that adolescents experienced fewer side effects with a triphasic levonorgestrel pill than with a monophasic norethindrone pill 3.
• Satisfaction with the contraceptive method was high among adolescents using levonorgestrel implants, with 93% of users expressing overall satisfaction despite experiencing side effects 4.

Continuation Rates and Effectiveness

• The studies found that the continuation rates and effectiveness of levonorgestrel and norethindrone varied, with one study finding that the final continuation rates at 12 months were 41.9% and 37.8% for the injectable contraceptive and oral contraceptive, respectively 2.
• Another study found that levonorgestrel implants provided superior protection against unintended pregnancy, with no pregnancies occurring among implant users, compared to six pregnancies among oral contraceptive users 4.
• The use of emergency contraception, including levonorgestrel, has also been discussed as a necessary option for adolescents seeking to prevent unintended pregnancy 6.