Birth Control Methods and Their Efficacy Rates
Long-acting reversible contraceptives (LARCs) are the most effective birth control methods, with failure rates of less than 1% per year, and should be presented first when counseling about contraceptive options. 1
Contraceptive Methods Ranked by Effectiveness
Most Effective Methods (>99% effective)
- Single-rod contraceptive implant (Implanon/Nexplanon): 0.05% failure rate
- Levonorgestrel IUD (Mirena): 0.2% failure rate
- Copper IUD (ParaGard): 0.8% failure rate
- Female sterilization: 0.5% failure rate
- Male sterilization: 0.15% failure rate
Highly Effective Methods (91-99% effective)
- DMPA injection (Depo-Provera): 6% typical use failure rate
- Combined hormonal methods (pills, patch, ring): 9% typical use failure rate
- Progestin-only pills: 9% typical use failure rate
Moderately Effective Methods (70-90% effective)
- Male condoms: 18% typical use failure rate
- Female condoms: 21% typical use failure rate
- Diaphragm: 12% typical use failure rate
- Withdrawal: 22% typical use failure rate
Least Effective Methods (<80% effective)
- Fertility awareness-based methods: 24% typical use failure rate
- Spermicides: 28% typical use failure rate
- No method: 85% pregnancy rate
Key Features of Most Effective Methods
Implants
- Highly effective with typical and perfect use failure rates of less than 0.05% 1
- User-independent and coitus-independent
- Effective for 3 years
- Rapid return to fertility after removal
- Main side effect is unpredictable bleeding patterns 1
IUDs
- Levonorgestrel IUD: 0.2% failure rate, approved for 3-5 years (depending on type)
- Copper IUD: 0.8% failure rate, approved for 10 years
- Both are safe for nulliparous women and adolescents 1
- Primary mechanism is preventing fertilization by inhibiting sperm motility 1
- High continuation rates (78-80% at 1 year) 1
Injectable Contraception (DMPA)
- 6% typical use failure rate
- Requires injection every 3 months
- 56% continuation rate at 1 year 1
Combined Hormonal Methods
- 9% typical use failure rate for pills, patch, and ring
- Requires consistent daily, weekly, or monthly use
- 67% continuation rate at 1 year 1
- Increased risk of venous thrombosis (7-10 events per 10,000 women-years compared to 2-10 events in non-users) 2
Important Considerations for Contraceptive Selection
Effectiveness Factors
- Perfect use refers to consistent and correct use every time
- Typical use includes varying degrees of adherence
- The gap between perfect and typical use is smallest with user-independent methods (LARCs) 1
Continuation Rates
- Higher continuation rates with LARCs (78-84% at 1 year)
- Lower continuation rates with user-dependent methods (41-67% at 1 year) 1
Safety Considerations
- Estrogen-containing methods increase risk of venous thrombosis 2
- Progestin-only and non-hormonal methods have fewer serious risks 2
- Medical eligibility criteria should be considered for each method 1
Non-Contraceptive Benefits
- Hormonal methods can improve conditions like acne, endometriosis, and premenstrual symptoms 2
- Extended-cycle regimens can reduce menstrual bleeding, cramping, and frequency 3
Common Pitfalls in Contraceptive Selection
Overestimating user adherence: The effectiveness gap between perfect and typical use is largest with user-dependent methods like pills and condoms.
Outdated concerns about IUDs: Modern IUDs are safe for nulliparous women and do not increase risk of pelvic inflammatory disease beyond the first 20 days after insertion 1.
Not considering continuation rates: Methods with higher discontinuation rates may lead to gaps in contraceptive coverage and unintended pregnancy.
Focusing only on contraceptive benefits: Consider non-contraceptive benefits and side effects when selecting a method.
Not discussing emergency contraception: Emergency contraception should be discussed as a backup option, with copper IUDs being the most effective emergency contraceptive (>99% effective) 3.
For optimal contraceptive effectiveness, counseling should prioritize the most effective methods first (LARCs), while considering the individual's medical eligibility, preferences, and ability to use the method consistently and correctly.