Safest Birth Control Method
Long-acting reversible contraception (LARC)—specifically the etonogestrel subdermal implant and levonorgestrel-releasing intrauterine devices (IUDs)—represent the safest birth control options, with failure rates below 1% and minimal serious health risks compared to other methods. 1
Efficacy and Safety Profile
Most Effective Methods (LARC)
The contraceptive implant has the lowest failure rate at 0.05% for both typical and perfect use, followed closely by levonorgestrel IUDs at 0.2%. 1 These methods provide:
- User-independent protection that eliminates adherence issues affecting other methods 1
- No estrogen-related risks such as venous thromboembolism, making them safe for women with estrogen contraindications 1
- Highest continuation rates at 80-84% at one year, compared to 56-67% for shorter-acting hormonal methods 1
Safety Advantages Over Other Methods
LARC methods avoid the cardiovascular risks associated with estrogen-containing contraceptives. Combined oral contraceptives increase venous thromboembolism risk from 2-10 events per 10,000 women-years to 7-10 events per 10,000 women-years 2. In contrast:
- Progestin-only implants and IUDs carry minimal serious health risks 2
- IUDs do not increase pelvic inflammatory disease risk beyond the first 20 days after insertion 1
- Previous concerns about IUD-related infertility have been disproven—infertility was attributable to STIs, not the device itself 1
Specific Method Recommendations
For Women Without Cardiovascular Disease
The etonogestrel implant (Nexplanon) is the single safest option, providing 3 years of protection with 1:
- Failure rate of 0.05% 1
- Safe for nulliparous women and adolescents 1
- No user action required after insertion 1
Common pitfall: The main reason for premature removal is unpredictable bleeding—patients must be thoroughly counseled about this before insertion 1.
For Women With Cardiovascular Disease
The levonorgestrel-releasing IUD is the safest and most effective option for women with cyanotic congenital heart disease, pulmonary vascular disease, or other cardiovascular conditions. 1 This method:
- Reduces menstrual blood loss by 40-50% 1
- Avoids systemic hormonal effects 1
- Has failure rates of 0.2% 1
Critical caveat: For women with highly complex heart disease (Fontan circulation, Eisenmenger syndrome), IUD insertion should only occur in a hospital setting due to 5% risk of vasovagal reactions 1.
Copper IUD Considerations
The copper T380-A IUD offers 10-12 years of hormone-free protection with a 0.6-0.8% failure rate 1, making it safe for women who cannot use hormonal methods. However:
- It is contraindicated in cyanotic women with hematocrit >55% due to increased menstrual bleeding risk 1
- It may increase menstrual bleeding in healthy women 1
Methods to Avoid for Safety Reasons
Combined hormonal contraceptives (pills, patch, ring) carry the highest serious health risks among reversible methods:
- Venous thromboembolism risk increases 3.5-5 fold 2
- Failure rates of 9% with typical use 1—significantly higher than LARC
- Require daily adherence, increasing pregnancy risk 1
Depot medroxyprogesterone acetate (DMPA) should be avoided in women with heart failure due to fluid retention tendency 1.
Clinical Implementation
When counseling patients, present methods in order of effectiveness, starting with LARC 1. The algorithm should be:
- First-line: Offer implant or levonorgestrel IUD based on patient preference and medical history 1
- Second-line: Copper IUD if hormones contraindicated and no bleeding concerns 1
- Third-line: Progestin-only pills for women who decline LARC 1
- Avoid: Combined hormonal methods in women >35 who smoke, have cardiovascular disease, or thrombophilia 1
For adolescents specifically, both ACOG and CDC support immediate postpartum LARC insertion to remove barriers to care, with no effects on breastfeeding performance or infant health 1.