Introduction

Emergency contraception (EC) is a method used to prevent pregnancy after unprotected sex or contraceptive failure, such as a broken condom or missed birth control pills. It is not intended for regular use but as a backup option to reduce the risk of unintended pregnancy. There are several types of emergency contraception available, each with different mechanisms of action, timing, and effectiveness. This lecture explores the various types of emergency contraception, how they work, and their effectiveness in preventing pregnancy.

1. Types of Emergency Contraception

A. Emergency Contraceptive Pills (ECPs)

1. Levonorgestrel-Based Pills (Plan B One-Step, Next Choice, etc.)

   • Description and Mechanism:

     • Levonorgestrel-based emergency contraceptive pills (ECPs) contain a high dose of levonorgestrel, a synthetic progestin. They work primarily by preventing or delaying ovulation, thereby reducing the chance of fertilization.
     • If taken before ovulation, these pills can effectively prevent the release of an egg. However, they do not work if ovulation has already occurred, and they do not terminate an established pregnancy.

   • Timing and Use:

     • Levonorgestrel-based ECPs are most effective when taken as soon as possible after unprotected intercourse, ideally within 72 hours (3 days). Their effectiveness decreases the longer the delay in taking them, but they can be taken up to 120 hours (5 days) after unprotected sex with reduced effectiveness.

   • Effectiveness:

     • When taken within 72 hours of unprotected intercourse, levonorgestrel-based ECPs reduce the risk of pregnancy by approximately 75-89%. Effectiveness decreases as the time between intercourse and pill intake increases.

   • Availability:

     • Levonorgestrel-based ECPs are available over-the-counter without a prescription in many countries.

2. Ulipristal Acetate (Ella)

   • Description and Mechanism:

     • Ulipristal acetate (brand name Ella) is a selective progesterone receptor modulator. It works by inhibiting or delaying ovulation, and it may also prevent implantation by altering the endometrial lining.
     • Ulipristal acetate is effective even if taken closer to the time of ovulation, making it a more effective option compared to levonorgestrel-based pills.

   • Timing and Use:

     • Ulipristal acetate is most effective when taken as soon as possible after unprotected intercourse and can be used up to 120 hours (5 days) after sex without a decrease in effectiveness.

   • Effectiveness:

     • Ulipristal acetate reduces the risk of pregnancy by about 85% when taken within 120 hours of unprotected sex. Unlike levonorgestrel, its effectiveness does not decrease significantly within this time frame.

   • Availability:

     • Ulipristal acetate typically requires a prescription and is not as widely available as levonorgestrel-based ECPs.

B. Copper Intrauterine Device (IUD) as Emergency Contraception

• Description and Mechanism:

  • The copper IUD (such as Paragard) is a small, T-shaped device made of plastic and copper that is inserted into the uterus by a healthcare provider. For emergency contraception, the copper IUD can be inserted up to 5 days after unprotected intercourse.
  • The copper IUD works by releasing copper ions, which create a hostile environment for sperm, preventing fertilization. It also alters the endometrial lining, preventing implantation if fertilization has already occurred.

• Timing and Use:

  • The copper IUD must be inserted by a healthcare provider within 120 hours (5 days) of unprotected intercourse. It is the most effective form of emergency contraception and provides ongoing contraception for up to 10-12 years after insertion.

• Effectiveness:

  • The copper IUD is over 99% effective as emergency contraception, making it the most effective EC option available. It works regardless of where a woman is in her menstrual cycle, including after ovulation.

• Availability:

  • The copper IUD requires a visit to a healthcare provider for insertion, and it may not be immediately accessible in all settings.

2. Mechanisms of Action

A. Prevention of Ovulation

• How It Works:
  • Both levonorgestrel-based pills and ulipristal acetate work primarily by preventing or delaying ovulation. By inhibiting the release of an egg from the ovary, these methods reduce the likelihood that sperm will encounter an egg for fertilization.
  • Timing is crucial for this mechanism, as the pills are most effective when taken before ovulation occurs.

B. Prevention of Fertilization and Implantation

• How It Works:
  • The copper IUD prevents fertilization by creating a toxic environment for sperm in the uterus and fallopian tubes. It may also prevent implantation by altering the uterine lining, though this is less certain.
  • Unlike ECPs, the copper IUD remains effective regardless of the timing of ovulation, as it directly interferes with sperm viability and motility.

3. Effectiveness and Considerations

A. Comparing Effectiveness

• Levonorgestrel-Based ECPs:

  • Most effective when taken within 72 hours of unprotected sex, with decreasing effectiveness up to 120 hours. Best used for women who are early in their menstrual cycle and have not yet ovulated.

• Ulipristal Acetate:

  • More effective than levonorgestrel-based pills, especially closer to ovulation. Effective for up to 120 hours without a significant decrease in effectiveness. Suitable for women who may be closer to ovulation.

• Copper IUD:

  • The most effective form of emergency contraception, with over 99% effectiveness. Works regardless of the timing of ovulation and provides ongoing contraception for up to 10-12 years.

B. Side Effects and Considerations

• Levonorgestrel-Based ECPs:

  • Side effects may include nausea, fatigue, headache, dizziness, breast tenderness, and changes in menstrual bleeding. These side effects are generally mild and short-lived.

• Ulipristal Acetate:

  • Side effects are similar to those of levonorgestrel-based ECPs but may also include delayed menstruation. It’s important to take a pregnancy test if the period is delayed by more than a week.

• Copper IUD:

  • Insertion can cause discomfort, cramping, and spotting. The copper IUD may also cause heavier periods and increased menstrual cramps, particularly in the first few months of use.

C. Accessibility and Cost

• Levonorgestrel-Based ECPs:

  • Widely available over-the-counter without a prescription in many countries, making them easily accessible. Cost may vary but is generally affordable.

• Ulipristal Acetate:

  • Requires a prescription and may be more expensive than levonorgestrel-based ECPs. Accessibility can be limited by availability in certain regions.

• Copper IUD:

  • Requires a visit to a healthcare provider for insertion, which can be a barrier to immediate access. The upfront cost may be higher, but it is cost-effective over time due to its long duration of use.

Real-World Case Studies

Case Study 1: Emergency Contraception After Condom Failure

Scenario:
A 25-year-old woman experiences a condom break during intercourse and is concerned about the risk of pregnancy. She is unsure which form of emergency contraception to use and wants to know her options.

Discussion Points:

• What are the pros and cons of levonorgestrel-based ECPs versus ulipristal acetate in this scenario?
• How does the timing of intercourse in relation to her menstrual cycle affect her choice?
• Should she consider the copper IUD for emergency contraception, and why?

Resolution:
The woman is advised that if she is early in her cycle and far from ovulation, levonorgestrel-based ECPs may be a suitable option, especially if she can take them within 72 hours. If she is closer to ovulation or wants a more effective option, ulipristal acetate may be better. If she desires ongoing contraception and the highest level of effectiveness, the copper IUD is recommended.

Case Study 2: Delayed Access to Emergency Contraception

Scenario:
A 30-year-old woman had unprotected sex four days ago and was unable to access emergency contraception immediately. She is now concerned about her options given the time that has passed.

Discussion Points:

• What are the most effective options for emergency contraception at this point?
• How does the timing affect the effectiveness of levonorgestrel-based ECPs compared to ulipristal acetate?
• What should she consider if choosing between ECPs and the copper IUD?

Resolution:
The woman is informed that since four days have passed, ulipristal acetate would be more effective than levonorgestrel-based ECPs, as it remains effective up to 120 hours after intercourse. The copper IUD is also highly recommended as it is the most effective option at this stage and offers ongoing contraception.

End of Lecture Quizzes

1. Which of the following is the most effective form of emergency contraception?

   • A) Levonorgestrel-based ECPs
   • B) Ulipristal acetate
   • C) Copper IUD
   • D) Combined oral contraceptive pills
     Answer: C
     Rationale: The copper IUD is over 99% effective as emergency contraception and works regardless of the timing of ovulation.

2. How soon should levonorgestrel-based ECPs be taken for maximum effectiveness?

   • A) Within 24 hours
   • B) Within 72 hours
   • C) Within 5 days
   • D) Within 7 days
     Answer: B
     Rationale: Levonorgestrel-based ECPs are most effective when taken within 72 hours of unprotected intercourse, with decreasing effectiveness up to 120 hours.

3. Which emergency contraceptive option requires a prescription?

   • A) Levonorgestrel-based ECPs
   • B) Copper IUD
   • C) Ulipristal acetate
   • D) Both B and C
     Answer: C
     Rationale: Ulipristal acetate typically requires a prescription, while the copper IUD requires a visit to a healthcare provider for insertion.

4. What is a common side effect of both levonorgestrel-based ECPs and ulipristal acetate?

   • A) Increased menstrual bleeding
   • B) Nausea
   • C) Weight gain
   • D) Hypertension
     Answer: B
     Rationale: Nausea is a common side effect of both levonorgestrel-based ECPs and ulipristal acetate.

Curated List of Online Resources for Further Information

1. Planned Parenthood – Emergency Contraception:
   Detailed information on types of emergency contraception, how they work, and where to obtain them.
   Planned Parenthood

2. Mayo Clinic – Emergency Contraception:
   Overview of emergency contraception options, including timing, effectiveness, and side effects.
   Mayo Clinic

3. Centers for Disease Control and Prevention (CDC) – Emergency Contraception:
   CDC guidelines on the use of emergency contraception and its effectiveness.
   CDC – Emergency Contraception

4. American College of Obstetricians and Gynecologists (ACOG) – Emergency Contraception:
   Clinical guidelines and patient resources on emergency contraception.
   ACOG

5. World Health Organization (WHO) – Emergency Contraception:
   Global perspectives on emergency contraception and its role in reproductive health.
   WHO – Emergency Contraception

Summary

Emergency contraception provides a vital option for preventing pregnancy after unprotected intercourse or contraceptive failure. The three main types of emergency contraception—levonorgestrel-based pills, ulipristal acetate, and the copper IUD—each offer different benefits, timing considerations, and effectiveness levels. Levonorgestrel-based pills are most effective within 72 hours, while ulipristal acetate remains effective for up to 120 hours. The copper IUD is the most effective option and offers ongoing contraception. Understanding the mechanisms, timing, and accessibility of these options is crucial for informed decision-making in emergency situations.

These lecture notes provide a comprehensive overview of emergency contraception, equipping students with the knowledge needed to understand the types, effectiveness, and considerations of each method.