What is a subdermal contraceptive (subcutaneous contraceptive)?

From the Guidelines

Subdermal contraceptives, such as Nexplanon, are a highly effective and recommended form of birth control, with a failure rate of 0.2% and approval for use up to 3 years, as stated in the study by the Society for Maternal-Fetal Medicine 1.

Key Points

• The subdermal implant, Nexplanon, contains 68 mg of etonogestrel and is inserted under the skin of the upper arm.
• It works by releasing a steady, low dose of progestin that prevents pregnancy in three ways: by stopping ovulation, thickening cervical mucus to block sperm, and thinning the uterine lining.
• The American College of Rheumatology guideline for the management of reproductive health in rheumatic and musculoskeletal diseases also recommends the use of subdermal progestin implants as a highly effective form of contraception, with a pregnancy rate of less than 1% per year 1.

Benefits and Considerations

• Subdermal contraceptives are over 99% effective, making them one of the most reliable contraceptive methods available.
• The implant is inserted during a quick office procedure using local anesthesia and lasts for up to 3 years, though it can be removed earlier if desired.
• Side effects may include irregular bleeding patterns (especially in the first 6-12 months), headaches, breast tenderness, and mood changes.
• The implant does not protect against sexually transmitted infections, so condoms are still recommended for STI prevention.
• Most women can use subdermal contraceptives safely, though they aren't recommended for those with certain conditions like current or past breast cancer, liver disease, or unexplained vaginal bleeding.

Recommendations

• The use of subdermal contraceptives, such as Nexplanon, is strongly recommended for women who desire a highly effective and long-acting form of birth control, as stated in the study by the American College of Rheumatology 1.
• Women with certain medical conditions, such as rheumatic and musculoskeletal diseases, may also benefit from the use of subdermal contraceptives, as they are a highly effective form of contraception with a low risk of adverse effects 1.

From the FDA Drug Label

The FDA drug label does not answer the question.

From the Research

Subdermal Contraceptive Implants

• Subdermal contraceptive implants involve the delivery of a steroid progestin from polymer capsules or rods placed under the skin, providing contraceptive effectiveness for 1-5 years 2.
• The period of protection depends upon the specific progestin and the type of polymer, with advantages including long-term contraceptive action without requiring user or provider attention, low dose of highly effective contraception without estrogen, and readily reversible fertility after implant removal 2.

Types of Subdermal Contraceptive Implants

• The levonorgestrel implant Norplant R system is the only one approved for distribution, with the highest observed contraceptive efficacy amongst effective methods and an annual pregnancy rate of 0.2 during the first and second year and 1.1 on the fifth year 2.
• Other implants under development include Norplant-2, Nestorone, 3-Keto-desogestrel, and Uniplant, which aim to simplify the method and minimize side effects 2.
• Implanon, a single rod etonogestrel implant, is currently approved for 3 years of use and provides excellent efficacy throughout its use, with ease of insertion and removal 3.

Safety and Efficacy

• Subdermal contraceptive implants have been shown to be safe to use during lactation, may improve dysmenorrhea, and do not significantly affect bone mineral density, lipid profile, or liver enzymes 3.
• Implanon has been found to be effective in treating endometrial intraepithelial neoplasia, with regression of the lesion observed after implant insertion 4.
• Studies have also demonstrated the efficacy and safety of Implanon in treating pelvic endometriosis, with relief of symptoms and satisfaction with treatment reported by women 5.

Acceptability and Return of Fertility

• Implanon has been found to be a safe, effective, and well-accepted method of contraception, with a high return of ovulation and pregnancy rate after removal 6.
• The majority of women who discontinued Implanon due to side effects, such as polymenorrhagia, irregular bleeding, or amenorrhea, did so within the first year of use 6.