What is the birth control patch, specifically Ortho Evra (ethinyl estradiol and norelgestromin), and how does it work?

Birth Control Patch: Everything You Need to Know

The birth control patch (Ortho Evra) is an effective contraceptive option with a 9% typical use failure rate, but due to its higher estrogen exposure (1.6 times that of combined oral contraceptives) and potentially increased risk of venous thromboembolism, other methods may be safer first-line choices for many women. 1

What Is the Birth Control Patch?

The birth control patch (Ortho Evra) is a transdermal contraceptive system that:

• Contains 0.6 mg norelgestromin and 0.75 mg ethinyl estradiol 1
• Measures approximately 1.75 × 1.75 inches 1
• Delivers 150 μg norelgestromin and 20 μg ethinyl estradiol daily to the bloodstream 2
• Is applied to the skin once weekly for three consecutive weeks, followed by one patch-free week 1

Application Sites

The patch can be placed on:

• Abdomen
• Upper torso (except breasts)
• Upper outer arm
• Buttocks 1

How Does It Work?

The birth control patch works through multiple mechanisms:

• Primary mechanism: Inhibition of ovulation through suppression of gonadotropins 3
• Secondary mechanisms:
  • Thickening cervical mucus to prevent sperm penetration 3
  • Inducing endometrial changes that reduce probability of implantation 3
  • Suppressing follicular development 3

Effectiveness

• Typical use failure rate: 9% (similar to combined oral contraceptives) 1
• Perfect use failure rate: Less than 1% 1
• Note: Effectiveness may be reduced in women weighing more than 198 pounds (90 kg) 1, 4

Advantages

• Weekly application instead of daily pill-taking 3
• Improved compliance compared to daily oral contraceptives in some studies 4, 3
• Not affected by vomiting or diarrhea (unlike oral contraceptives) 1
• Provides a simple regimen with comparable efficacy to other combined hormonal methods 1

Disadvantages and Side Effects

Major Concerns

• Higher estrogen exposure: 1.6 times higher than with low-dose combined oral contraceptives 1, 2
• Increased VTE risk: Potentially twice the risk compared to combined oral contraceptives, with odds ratios of 1.2 to 2.2 1, 2

Common Side Effects

• Breast symptoms/tenderness (more common than with oral contraceptives) 4, 3
• Headache 4
• Nausea and vomiting 4
• Dysmenorrhea 4
• Abdominal pain 4

Unique to the Patch

• Application site reactions (irritation, redness) 4, 3
• Patch detachment issues: approximately 5% of users experienced at least one patch that did not stay attached 4
• Skin effects: hyperpigmentation, contact dermatitis 1

Practical Considerations

What to Do if the Patch Detaches or Application Is Delayed

If detachment or delayed application is less than 48 hours:

• Apply a new patch as soon as possible
• Keep the same patch change day
• No additional contraceptive protection needed 1

If detachment or delayed application is 48 hours or more:

• Apply a new patch immediately
• Use backup contraception (e.g., condoms) for 7 consecutive days
• If in the third patch week, omit the hormone-free week and start a new patch immediately 1

Adhesion Concerns

• Physical exercise, water immersion, and humid climates do not significantly affect patch adhesion 3
• Less than 2% of patches need replacement due to complete detachment 5, 3

Important Warnings and Precautions

• The FDA has issued a black box warning about the potentially increased risk of venous thromboembolism 1
• Women with risk factors for thrombosis should consider alternative methods
• The patch may be less effective in women weighing more than 198 pounds 1
• The patch has the same contraindications as other combined hormonal contraceptives

Continuation Rates

Despite theoretical advantages of weekly versus daily dosing, some studies have shown lower continuation rates with the patch:

• One study found 57% continuation of the patch at 1 year compared to 76% for the pill 1
• This suggests that ease of use doesn't necessarily translate to better long-term adherence

Clinical Bottom Line

While the birth control patch offers convenience through weekly application, its higher estrogen exposure and potentially increased VTE risk make it a second-line option for many women. Other methods like combined oral contraceptives, vaginal rings, or long-acting reversible contraceptives may offer better safety profiles while maintaining similar or better efficacy. The decision to use the patch should carefully weigh these risks against the benefits of a weekly dosing schedule, particularly for women who struggle with daily pill adherence.