Emergency contraceptives are effective if used within

Options

A. coitus
B. ovulation
C. menstruation
D. implantation

Explanation

**Step-by-Step Solution:**

1. **Understanding Emergency Contraceptives**: Emergency contraceptives are medications designed to prevent pregnancy after unprotected sexual intercourse or contraceptive failure.

2. **Time Frame for Effectiveness**: These contraceptives are most effective when taken within a specific time frame. Research indicates that they should be used within 72 hours (3 days) after coitus (sexual intercourse).

3. **Mechanism of Action**: The primary mechanism of emergency contraceptives is to delay or disrupt ovulation. This means that they work by preventing the ovary from releasing an egg, which in turn reduces the chances of fertilization.

4. **Types of Emergency Contraceptives**: Emergency contraceptives can include high doses of progesterone or combinations of progesterone and estrogen. These hormones play a crucial role in regulating the menstrual cycle and can prevent pregnancy when taken within the appropriate time frame.

5. **Conclusion**: Based on the information provided, emergency contraceptives are effective if used within 72 hours of coitus.

**Final Answer**: Emergency contraceptives are effective if used within **72 hours of coitus**.

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