Questions: A client who has become sexually active asks, "What's the most effective way to prevent a pregnancy?" Which method of preventing pregnancy would the nurse tell her is most effective? Using birth control pills Using spermicidal foam Abstaining from sexual intercourse Having an intrauterine device inserted

The answer is the third one: Abstaining from sexual intercourse.

Explanation for each option:

1. Using birth control pills: Birth control pills are highly effective when taken correctly, with a typical use effectiveness rate of about 91%. However, they are not the most effective method because they rely on consistent and correct usage.

2. Using spermicidal foam: Spermicidal foam is less effective compared to other methods, with a typical use effectiveness rate of about 72%. It is often used in combination with other methods to increase effectiveness.

3. Abstaining from sexual intercourse: This is the most effective way to prevent pregnancy, as it completely eliminates the possibility of sperm fertilizing an egg. It is 100% effective in preventing pregnancy.

4. Having an intrauterine device inserted: Intrauterine devices (IUDs) are one of the most effective forms of reversible contraception, with an effectiveness rate of over 99%. However, they are slightly less effective than complete abstinence.

In summary, while IUDs and birth control pills are highly effective, abstaining from sexual intercourse is the only method that is 100% effective in preventing pregnancy.