Common side effects of emergency contraception
After taking an emergency contraceptive (EC) pill, such as a levonorgestrel-based pill (like Plan B One-Step) or ulipristal acetate (ella), some users may experience temporary side effects. These are generally mild and subside within a day or two as the body adjusts to the temporary hormonal surge.
Mild and temporary symptoms
Most side effects are manageable and short-lived. A few of the most commonly reported temporary symptoms include:
- Nausea: An upset stomach is one of the most frequent side effects, sometimes accompanied by vomiting. If vomiting occurs within two hours of taking the pill, a healthcare provider should be consulted about a potential second dose.
- Headache: Mild to moderate headaches can be a temporary response to the hormonal changes.
- Dizziness and fatigue: Feeling tired, dizzy, or lightheaded is common for some users following EC pill use.
- Breast tenderness: Some individuals may experience temporary soreness or tenderness in their breasts.
- Abdominal pain: Mild cramps or lower stomach pain are possible side effects.
Menstrual cycle changes
One of the most notable short-term negatives of the emergency pill is its potential to temporarily disrupt the menstrual cycle. The high dose of hormones can cause irregular bleeding or changes to the timing and flow of your next period.
- Irregular bleeding (spotting): Light bleeding or spotting may occur between periods.
- Delayed or early period: The next menstrual period may arrive earlier or later than expected, often by a few days to a week. If a period is more than a week late, a pregnancy test is recommended.
- Heavier or lighter flow: The heaviness or lightness of the next period may also be different from a normal cycle.
Factors affecting effectiveness
Emergency contraceptive pills are not foolproof and their effectiveness can be compromised by several factors. Unlike more consistent birth control methods, they are less effective overall.
Timing is a key factor
The effectiveness of oral EC is highly dependent on how soon it is taken after unprotected sex. Both levonorgestrel and ulipristal acetate pills are most effective when taken as soon as possible. As time passes, their efficacy decreases, especially for levonorgestrel. Ulipristal acetate maintains a higher level of effectiveness for the entire 5-day window, but it is still recommended to take it promptly.
Body weight considerations
For individuals with a higher body mass index (BMI), certain EC pills may be less effective at preventing pregnancy. Studies indicate that levonorgestrel-based pills, like Plan B, may lose efficacy in individuals weighing over 165 pounds or with a BMI over 30. Ulipristal acetate (ella) is a more effective option for heavier individuals, though its efficacy can also decrease at higher weight thresholds. The most effective emergency contraception for individuals of all body weights is a copper intrauterine device (IUD).
Medication interactions
Certain medications can interfere with the effectiveness of emergency pills. For example, drugs like some anti-seizure medications and the herbal supplement St. John's wort can decrease the efficacy of levonorgestrel and ulipristal acetate. It is important to consult a healthcare provider about potential drug interactions.
Limitations and downsides of use
Understanding the limitations of emergency contraception is essential for making informed decisions about sexual health. It is not designed to be a routine form of contraception and has other important drawbacks.
- No STI protection: The emergency pill does not protect against sexually transmitted infections (STIs), including HIV. Consistent and correct condom use is necessary for STI prevention.
- Not for regular use: Because hormonal EC pills are significantly less effective than long-term birth control methods, relying on them frequently is not recommended. Frequent use can also lead to unpredictable and irregular menstrual cycles.
- Potential for failure: Even when taken correctly, emergency pills can fail. The primary sign of failure is a missed period, at which point a pregnancy test is advised.
Ectopic pregnancy: Understanding the risk
An ectopic pregnancy is a medical emergency where a fertilized egg implants and grows outside the uterus, most often in the fallopian tube. Some early studies and case reports raised concerns about a potential link between hormonal EC failure and ectopic pregnancy, suggesting EC might increase the risk. However, larger reviews and more recent studies have found that the rate of ectopic pregnancy following EC pill failure does not exceed the rate observed in the general population. Instead, by effectively preventing pregnancy, EC reduces the chance that any act of unprotected sex will result in an ectopic pregnancy.
This means that taking an EC pill does not increase the risk of an ectopic pregnancy. However, if a user experiences severe abdominal pain or abnormal bleeding after taking an EC pill, it is crucial to seek immediate medical attention, as these can be symptoms of an ectopic pregnancy.
Comparison of oral emergency contraceptive pills
| Feature | Levonorgestrel (e.g., Plan B One-Step) | Ulipristal Acetate (ella) |
|---|---|---|
| Availability | Available over-the-counter for all ages in the U.S. No prescription needed. | Requires a prescription from a healthcare provider. |
| Timeframe for use | Most effective within 72 hours (3 days), but can be used up to 120 hours (5 days). Efficacy declines over time. | Can be used up to 120 hours (5 days) after unprotected sex. Maintains effectiveness throughout the window. |
| Effectiveness by weight | May be less effective in individuals over 165 pounds or with a BMI over 30. | Effective for individuals with a BMI up to 35, making it a better option for heavier individuals. |
| Mechanism | Works primarily by delaying or preventing ovulation. | Delays ovulation even when the luteinizing hormone (LH) surge has already begun. |
| Resuming regular contraception | Can resume or start regular hormonal birth control immediately after taking. | Wait at least 5 days to begin or resume hormonal birth control, as it can reduce ella's effectiveness. |
Conclusion
While emergency contraceptive pills are a vital tool for preventing unintended pregnancy, they come with a distinct set of negatives and considerations. Users should be prepared for temporary side effects such as nausea, headaches, and a disrupted menstrual cycle. More importantly, understanding the limitations regarding decreased effectiveness over time and for individuals with higher body weight (especially for levonorgestrel) is critical for success. EC pills do not offer protection against STIs and are significantly less effective than regular, long-term contraception. However, it is a common misconception that EC causes long-term fertility issues or increases the rate of ectopic pregnancy. By understanding these nuances, individuals can make the most informed choices for their reproductive health, opting for more reliable, long-term contraception if frequent use is anticipated.
