The Cardinal Rule: Don't Be Inconsistent
The single most significant factor that reduces the pill's effectiveness is not taking it correctly [1.2.5]. Oral contraceptives work by maintaining a steady level of hormones in your body. Forgetting to take your pill, or not taking it at the same time each day, can disrupt this balance and potentially lead to ovulation.
- Combination Pills (Estrogen and Progestin): While these are more forgiving, you should still aim to take them at the same time daily to build a habit. If you miss one pill, take it as soon as you remember, even if it means taking two in one day. No backup contraception is usually needed [1.6.3]. If you miss two or more pills, you should use a backup method like condoms for seven days [1.6.5].
- Progestin-Only Pills (Mini-Pills): These are much more time-sensitive. You must take a progestin-only pill within the same three-hour window every day. If you take it more than three hours late, you should use a backup method for the next 48 hours [1.9.3].
Don't Ignore Drug and Supplement Interactions
Many people are unaware that other medications and even herbal supplements can interfere with how your body processes oral contraceptives, potentially rendering them less effective [1.2.4].
Medications That Can Interfere
Always inform your doctor and pharmacist that you are on birth control before starting any new medication. Some known drugs that can decrease the pill's efficacy include:
- Certain Antibiotics: Specifically rifampin and rifabutin [1.3.4]. While many common antibiotics don't have a significant effect, it's always best to check [1.2.3].
- Some Antifungals: Griseofulvin is a key example [1.2.3].
- Certain Antiseizure Medications: Drugs like carbamazepine, phenytoin, and topiramate can lower hormone levels [1.3.5, 1.2.2].
- Antiretrovirals for HIV: Medications like efavirenz and some protease inhibitors can interact with the pill [1.3.4].
- The Anti-Nausea Medication Emend (aprepitant): This requires a backup method during and for one month after use [1.2.3].
Herbal Supplements to Avoid
The most well-documented supplement to avoid is St. John's Wort. It is known to speed up the breakdown of contraceptive hormones, which can lead to breakthrough bleeding and increase the risk of an unwanted pregnancy [1.4.3, 1.4.6]. Other supplements like alfalfa and saw palmetto may also interfere with hormone levels [1.4.5].
Don't Engage in Risky Lifestyle Habits
Your daily habits can also play a role in both the pill's effectiveness and your overall health while taking it.
Smoking
This is the most critical lifestyle factor. Smoking while using combination birth control pills dramatically increases your risk of serious cardiovascular side effects, including blood clots, heart attack, and stroke [1.5.6]. This risk is especially high for women over 35 who smoke [1.5.6].
Excessive Alcohol
Alcohol itself doesn't directly make the pill less effective. However, it can lead to mistakes. Intoxication can cause you to forget to take your pill on time [1.5.2]. Furthermore, if you vomit within two hours of taking your pill, it may not have been fully absorbed, and you should treat it as a missed dose [1.5.3].
Comparison of Common Mistakes and Risks
| Factor / Mistake | Risk Level | Why It's a Problem | Recommended Action |
|---|---|---|---|
| Missing One Combination Pill | Low | A minor dip in hormone levels. | Take the pill as soon as you remember. No backup method needed [1.6.3]. |
| Missing a Progestin-Only Pill by >3 Hrs | Moderate | The window of protection is very short, risking ovulation. | Take the pill immediately and use a backup method (e.g., condoms) for 48 hours [1.9.3]. |
| Vomiting/Severe Diarrhea | Moderate | The pill's hormones may not be fully absorbed by the body [1.2.5]. | Use a backup method of contraception for the next seven days [1.6.1]. |
| Taking St. John's Wort | High | Accelerates the breakdown of contraceptive hormones, reducing effectiveness [1.4.3]. | Stop taking the supplement and use a reliable backup method. Consult your doctor. |
| Smoking (especially if over 35) | Very High | Dramatically increases the risk of blood clots, stroke, and heart attack [1.5.6]. | It is strongly advised to quit smoking. Discuss estrogen-free contraceptive options with your doctor [1.2.2]. |
Don't Ignore Serious Warning Signs
A helpful acronym to remember the rare but serious side effects of the pill is ACHES [1.7.1, 1.7.4]. Contact your doctor immediately if you experience any of these:
- Abdominal pain (severe)
- Chest pain (severe), shortness of breath, or coughing up blood
- Headaches (severe)
- Eye problems (blurred vision, loss of vision)
- Severe leg pain or swelling
These symptoms can indicate a serious problem like a blood clot, stroke, or liver issue [1.7.4].
Conclusion: Empower Your Health Choices
Taking the pill is a reliable method of contraception, but its success depends heavily on correct and consistent use. By knowing what not to do when taking the pill—from avoiding certain medications and supplements to making smart lifestyle choices and recognizing warning signs—you take control of your reproductive health. Always keep an open line of communication with your healthcare provider to ensure your chosen method remains safe and effective for you.
For more detailed information on contraceptive methods, a great resource is Planned Parenthood.
