Birth Control Patch: Effectiveness and Usage
The birth control patch (Ortho Evra) is an effective contraceptive option with a typical use failure rate of 9%, similar to combined oral contraceptives, but offers the convenience of weekly application rather than daily dosing. 1
What Is the Birth Control Patch?
The birth control patch is a transdermal contraceptive system that:
- Contains 0.6 mg norelgestromin and 0.75 mg ethinyl estradiol 1, 2
- Delivers approximately 150 mcg norelgestromin and 35 mcg ethinyl estradiol daily 2, 3
- Measures approximately 1.75 × 1.75 inches (15.75 cm²) 1, 2
- Is applied once weekly for three consecutive weeks, followed by one patch-free week 1
Application and Usage Instructions
The patch should be applied to:
- Abdomen
- Upper torso (excluding breasts)
- Upper outer arm
- Buttocks 1
Usage schedule:
- Apply a new patch on the same day each week for three consecutive weeks
- Remove the patch during week 4 (patch-free week)
- Apply a new patch after the 7-day patch-free interval 1
Effectiveness
- Typical use failure rate: 9% (similar to combined oral contraceptives) 1
- Perfect use failure rate: <1% 1
- Important note: Effectiveness may be reduced in women weighing more than 198 pounds (90 kg), with perfect use failure rates of 0.9% versus 0.3% in women weighing less 1, 4
Mechanism of Action
The patch works primarily by:
- Inhibiting ovulation through suppression of gonadotropins
- Thickening cervical mucus
- Altering the endometrium to reduce probability of implantation 5
Advantages
- Weekly application instead of daily dosing
- Better adherence rates compared to oral contraceptives (87-93% perfect use reported in adolescent studies) 1
- Less than 2% of patches require replacement due to complete detachment 6
- Not affected by physical exercise, water immersion, or humid climates 5, 4
- Eliminates variability in gastrointestinal absorption and avoids hepatic first-pass metabolism 7
Side Effects and Risks
The patch has similar side effects to combined oral contraceptives, plus some unique effects:
Common side effects:
- Breakthrough bleeding/spotting
- Breast tenderness (may be more common than with oral contraceptives)
- Headaches
- Nausea 1, 5
Patch-specific side effects:
- Application site reactions (redness, irritation)
- Skin effects (hyperpigmentation, contact dermatitis) 1
Important safety concerns:
- Higher estrogen exposure: The patch delivers 1.6 times higher estrogen exposure than a low-dose combined oral contraceptive 1
- Increased VTE risk: The 2012 package insert contains a black box warning citing studies suggesting a possible increased risk of venous thromboembolism (VTE) compared to combined oral contraceptives, with odds ratios of 1.2 to 2.2 1, 3
Management of Delayed Application or Detachment
If patch detachment or delayed application occurs:
- Less than 48 hours: Apply a new patch immediately and keep the same patch change day. No additional contraceptive protection needed 1
- 48 hours or more: Apply a new patch immediately, but use backup contraception (e.g., condoms) for 7 consecutive days 1
- If delayed application or detachment occurs in the third patch week, omit the hormone-free week and start a new patch immediately 1
Practical Considerations
- Store at 20° to 25°C (68° to 77°F) 2
- Do not store unpouched 2
- Apply immediately upon removal from pouch 2
- The patch does not protect against HIV or other sexually transmitted infections 2
Who Should Consider Other Methods
- Women weighing more than 198 pounds (90 kg) due to slightly reduced efficacy 1, 4
- Women at high risk for venous thromboembolism 1
- Women concerned about the higher estrogen exposure compared to combined oral contraceptives 1
- Women who experience significant skin reactions to the patch 1
The birth control patch provides an effective alternative to daily oral contraceptives with the benefit of weekly application, but users should be aware of the increased estrogen exposure and potentially higher risk of venous thromboembolism compared to combined oral contraceptives.