Plan B, or the “morning-after pill,” is an over-the-counter emergency contraceptive containing a high dose of the hormone levonorgestrel. It is designed to be used after unprotected sex or birth control failure to prevent pregnancy. While a valuable tool for contraception, it is crucial for users to understand its downsides, including potential side effects, limitations in efficacy, and its role compared to other contraceptive methods.
Common Side Effects
As with most medications, Plan B can cause a range of side effects, which typically resolve within a few days. These are generally temporary and harmless but can be uncomfortable for some individuals.
- Changes to your next period: Your next menstrual cycle may be heavier, lighter, earlier, or later than usual. Spotting or irregular bleeding between periods is also common.
- Nausea and vomiting: These are frequently reported side effects. If you vomit within two hours of taking the pill, you should contact a healthcare professional to determine if another dose is needed.
- Abdominal pain or cramps: Lower stomach discomfort is a possible side effect.
- Fatigue, headache, and dizziness: These symptoms can be experienced temporarily after taking the pill.
- Breast tenderness: Some users may experience temporary breast pain or tenderness.
Effectiveness is Not Guaranteed
Plan B is not 100% effective and its efficacy can be influenced by several factors. Its effectiveness decreases over time, and it is less reliable than routine contraception.
- Timing is critical: While Plan B can be taken up to 72 hours (three days) after unprotected sex, it is most effective the sooner it is taken. Its efficacy declines with each passing hour.
- Body weight: Studies suggest that levonorgestrel-based emergency contraception, like Plan B, may be less effective for individuals with a higher body mass index (BMI). For those over 165 pounds, other options like Ella or a copper IUD may be more effective.
- Ovulation timing: Plan B works by delaying or preventing ovulation. If ovulation has already occurred, the pill will not be effective.
- Drug interactions: Certain medications and herbal supplements can make Plan B less effective. These include some medications for seizures, tuberculosis, HIV/AIDS, and St. John's wort.
Key Differences from Regular Birth Control
Plan B is a backup method, not a primary form of contraception. It is important to distinguish it from regular birth control.
- Not a long-term solution: Relying on Plan B for routine contraception is less effective, more expensive, and can cause more side effects than regular birth control methods.
- No STI protection: Plan B provides no protection against sexually transmitted infections (STIs). Regular use of condoms is necessary for STI prevention.
- Higher hormone dose: Plan B contains a much higher dose of hormones than daily birth control pills, which is why it can cause more noticeable side effects.
- Not an abortion pill: The high-dose levonorgestrel in Plan B works to prevent pregnancy before it starts; it will not end an existing pregnancy. The medication abortion pill (mifepristone) works differently and is used to terminate a pregnancy.
When to Seek Medical Attention
While most side effects are mild, certain symptoms after taking Plan B warrant immediate medical attention.
- Severe lower abdominal pain: This could be a sign of an ectopic pregnancy, a rare but life-threatening condition where a fertilized egg implants outside the uterus. If you experience this symptom, especially with unusual vaginal bleeding, see a doctor immediately.
- Heavy bleeding: If you experience abnormally heavy bleeding or persistent irregular bleeding, it is important to contact a healthcare provider.
- Late period: If your period is more than a week late after taking Plan B, you should take a pregnancy test and consult a healthcare professional.
Alternative Emergency Contraception Options
For those concerned about the downsides of Plan B or seeking more effective options, alternatives are available.
| Feature | Plan B (Levonorgestrel) | Ella (Ulipristal Acetate) | Copper IUD (Paragard) |
|---|---|---|---|
| Availability | Over-the-counter; no ID or prescription needed | Prescription only | Doctor's office insertion only |
| Timing | Within 72 hours (3 days), but sooner is better | Up to 120 hours (5 days); effectiveness consistent throughout | Up to 120 hours (5 days); most effective option |
| Effectiveness | 75-89% when taken within 72 hours | More effective than Plan B, especially closer to ovulation | Over 99% effective |
| Effect on Weight | Less effective for individuals over 165 lbs | Effective for individuals up to 195 lbs | Not affected by weight |
| Long-Term Use | Backup method only | Backup method only | Can provide long-term contraception for up to 10 years |
Conclusion: Weighing the Downsides of Plan B
Plan B is a safe and effective option for preventing unplanned pregnancy after unprotected sex. However, its downsides—including potential temporary side effects, reduced effectiveness over time and with higher body weight, and lack of STI protection—highlight that it should be used as a backup, not a primary, birth control method. Being aware of these limitations allows for a more informed decision regarding reproductive health. For ongoing contraception, or if you need emergency contraception outside of Plan B's optimal window or weight range, other options are more effective and reliable.
Sources:
- Plan B One-Step®: How Plan B Works
- CVS: Plan B One-Step Emergency Contraceptive Tablet
- Plan B One-Step®: Plan B FAQs
- Deacon Health | Wake Forest University: Morning After Pill
- Planned Parenthood: Plan B Morning-After Pill | How Plan B Works & Side Effects
- NPR: How Plan B and other emergency contraception work
- Planned Parenthood: How often can you take the morning-after pill?
- Planned Parenthood: What Kind of Emergency Contraception Is Best For Me?
- GoodRx: Levonorgestrel (Plan B One-Step): Uses, Side Effects, Dosage & …
