Grade by Grade
C. Healthy Living · Healthy Living: Informed Choices for Body, Mind and Relationships

Preventing Unintended Pregnancy and STIs: Methods, Effectiveness and Support

C1.4About 70 minutes
Learning goals
  • I can describe methods of preventing unintended pregnancy and compare how effective they are.
  • I can describe ways to prevent sexually transmitted infections (STIs), including HIV, and how effective they are.
  • I can explain why abstinence is the only method that is 100% effective and why dual protection is used by people who are sexually active.
  • I can identify reliable sources of information and support in Ontario.

Words to know

abstinence
Choosing not to have sexual activity. When practised consistently, it is 100% effective at preventing pregnancy and sexually transmitted infections.
contraception
Methods used to prevent pregnancy, also called birth control.
STI (sexually transmitted infection)
An infection passed from one person to another through sexual contact, such as chlamydia, gonorrhea, syphilis, HPV, herpes or HIV. Also called STBBIs (sexually transmitted and blood-borne infections).
HIV
Human immunodeficiency virus, which attacks the immune system. Without treatment it can lead to AIDS (acquired immunodeficiency syndrome). It is treatable but not curable.
typical use
How well a method works in real life, including mistakes like forgetting a pill or not using a condom every time.
perfect use
How well a method works when used correctly every single time.
dual protection
Using a condom (for STIs and pregnancy) plus another method (for extra pregnancy protection).

A note before you start

This lesson is part of Ontario's human development and sexual health learning for Grade 9. It sticks to facts and uses the correct terms. Read it with a trusted adult if you can, and remember: any question you have is a good question to ask a parent, a doctor or nurse, or a school counsellor.

Knowing the facts before you need them

Most Grade 9 students are not sexually active, and choosing to wait is common and healthy. But everyone deserves accurate information before they ever need it, so that when they do make decisions, now or years from now, they make them safely.

The Grade 9 curriculum asks you to describe the relative effectiveness of various methods of preventing unintended pregnancy or sexually transmitted infections, including HIV/AIDS, and identify sources of information and support (C1.4).

Remember from Grade 8

In Grade 8 you learned which methods protect against pregnancy, which protect against STBBIs, and which do both (abstinence and condoms), and the essentials of consent. This year you'll compare how effective each method is, and why.

Perfect use vs. typical use

Every method has two effectiveness numbers:

  • Perfect use: used exactly right, every time.
  • Typical use: real life, including mistakes (a missed pill, a condom put on late or not used every time).

Typical use is the more honest number for planning. Methods that don't depend on remembering something each day or each time (like an IUD) have typical-use rates very close to perfect use.

Typical-use effectiveness at preventing pregnancy (first year)Abstinence (used every time)100%IUD (hormonal or copper)more than 99%Injection (shot)about 96%Pill, patch or ringabout 93%External condomabout 87%Withdrawalabout 80%Internal condomabout 79%Percent of people who do NOT become pregnant in a year of typical (real-life) use. Approximate.
Approximate typical-use effectiveness at preventing pregnancy (based on widely used figures from public health agencies). Abstinence used consistently is 100%; withdrawal is one of the least reliable methods.
MethodHow it worksPregnancy protection (typical use)STI protection
AbstinenceNo sexual activity100% when used consistently100% from sexual contact
External condomA thin latex or non-latex cover worn on the penis; blocks sperm and fluidsAbout 87%Yes, lowers risk of many STIs including HIV
Internal condomA pouch inserted into the vagina; blocks sperm and fluidsAbout 79%Yes, lowers risk of many STIs
Pill, patch or ringHormones stop ovulation; must be taken or changed on scheduleAbout 93%No
InjectionHormone shot from a health care provider every 3 monthsAbout 96%No
IUD (hormonal or copper)Small device placed in the uterus by a health care provider; lasts yearsMore than 99%No
Emergency contraceptionPills taken after unprotected sex, or a copper IUD inserted within a few daysLowers the chance of pregnancy; works best the sooner it's usedNo
WithdrawalPulling out before ejaculationAbout 80%; not reliableNo
Methods compared. Only abstinence and condoms protect against both pregnancy and STIs.

Preventing STIs, including HIV

  • Abstinence from sexual contact.
  • Condoms (external or internal), used correctly every time, greatly lower the risk of many STIs, including HIV. They protect less against infections spread by skin-to-skin contact (HPV, herpes) because they don't cover all skin.
  • Vaccines: HPV and hepatitis B vaccines are offered free to Grade 7 students in Ontario school clinics. If you missed them, ask your doctor or public health unit about catch-up doses (many students can still get them free).
  • Testing: many STIs have no symptoms. Regular testing for sexually active people finds infections early. Bacterial STIs like chlamydia, gonorrhea and syphilis are curable with antibiotics; viral STIs like HIV and herpes are treatable but not curable.
  • HIV facts: HIV spreads through blood, semen, pre-seminal fluid, vaginal fluids, rectal fluids and breast milk, including by sharing needles. It does not spread by hugging, sharing food, toilet seats or mosquito bites. People with HIV who take treatment and keep the virus undetectable do not pass it on through sex. PrEP is a medication that people at higher risk can take to prevent HIV.
  • Don't share needles (for drugs, tattoos or piercings).
Which methods protect against what?Pregnancy onlySTIs onlyBothpill, patch, ringinjectionIUDemergencycontraceptionHPV vaccinehepatitis BvaccinePrEP (for HIV)abstinenceexternal orinternal condoms(used correctly,every time)Condoms lower the risk of many STIs but do not prevent every one (e.g. HPV, herpes).
Only abstinence and condoms sit in the middle: they lower the risk of both pregnancy and STIs. That's why people who are sexually active often use dual protection: a condom plus another method.

Sources of information and support in Ontario

  • Your doctor or nurse practitioner, or a sexual health clinic run by your local public health unit (free and confidential, including STI testing and low-cost birth control).
  • In Ontario, there is no minimum age to consent to your own health care; it depends on whether you understand the treatment. Health care providers keep your information confidential, except in rare situations involving safety.
  • Pharmacists (emergency contraception is sold without a prescription in Canada).
  • Sexandu.ca (a Canadian sexual health website from the Society of Obstetricians and Gynaecologists of Canada).
  • Kids Help Phone: 1-800-668-6868 or text CONNECT to 686868.
  • Trusted adults: parents and caregivers, school nurses or counsellors.
Worked example

Let's read the effectiveness numbers

100 couples use a method for one year. About how many pregnancies would you expect with typical use of (a) the pill, (b) external condoms, (c) an IUD?

  1. Typical-use effectiveness of the pill is about 93%, so about 7 in 100 become pregnant.
  2. External condoms: about 87%, so about 13 in 100.
  3. IUD: more than 99%, so fewer than 1 in 100.
  4. Why the difference? The pill must be taken every day and condoms used correctly every time. Mistakes happen. An IUD works without daily action.

About 7 (pill), 13 (condoms) and fewer than 1 (IUD). Effectiveness depends on the method and on how consistently it's used.

Worked example

Let's choose protection for two goals

A person who is sexually active wants the best protection against both pregnancy and STIs. Using the table and the diagram, what would you recommend and why?

  1. The hormonal and IUD methods are very effective for pregnancy but give no STI protection.
  2. Condoms protect against both, but typical-use pregnancy protection is lower.
  3. Combining a condom with a highly effective method (like an IUD or the pill) covers both goals: this is dual protection.
  4. Add regular STI testing and vaccines (HPV, hepatitis B).
  5. And remember: abstinence (choosing not to have sex, or to wait) is always an option and the only 100% method.

Dual protection (condom plus another method), regular testing and vaccination, or choosing abstinence. A health care provider can help choose.

Hands-on activity

Find your local support

You need: a computer or phone and a grown-up.

  1. Search for your local public health unit and find its sexual health clinic page. Write down: address, hours, phone number, and whether you need an appointment.
  2. Write down two reliable websites from this lesson and one way to tell if a site is reliable (made by health professionals or government; no ads selling products; up-to-date).
  3. Write three questions you might one day ask a doctor or nurse (e.g. "How do I know if a method is right for me?").
  4. Share the list with your grown-up and talk about which adults you could go to with questions.

What to look for: correct local information, reliable sources, and respectful, practical questions.

Your turn

1

Which method is 100% effective at preventing pregnancy and STIs when used consistently?

2

Which two methods protect against both pregnancy and STIs?

3

What is the difference between perfect use and typical use?

4

About how effective is the pill with typical use?

5

Name three STIs that are curable with antibiotics.

6

Name two ways HIV is not spread.

7

Name two places a teen in Ontario can get confidential sexual health information.

More practice: warm-up

1

Do birth control pills protect against STIs?

2

What does STI stand for?

3

Which vaccine offered in Grade 7 protects against a virus that can cause several cancers?

4

Is withdrawal a reliable method?

5

Can many STIs have no symptoms?

More practice: on your own

1

Explain why an IUD's typical-use effectiveness is almost the same as its perfect-use effectiveness.

2

Why do condoms protect less against HPV and herpes than against HIV?

3

Explain dual protection and why people use it.

4

A friend says, "I'd know if I had an STI." Respond accurately.

5

What is emergency contraception and when is it used?

Challenge

1

Rank these from most to least effective at preventing pregnancy (typical use): withdrawal, IUD, pill, external condom, injection. Explain the pattern.

2

Evaluate this claim: "The pill is 99% effective, so you don't need anything else."

3

Explain how the law and health system in Ontario help teens get sexual health care, and why confidentiality matters.

Check your understanding

Quiz

1.

Which is the only method that is 100% effective at preventing both pregnancy and STIs?

2.

Which method protects against both pregnancy and many STIs?

3.

"Typical use" effectiveness means...

4.

Which STI is caused by bacteria and curable with antibiotics?

5.

HIV can be spread by...

6.

Which is the most effective at preventing pregnancy with typical use?

For parents and teachers

About this content: This lesson is part of the human development and sexual health expectations of Ontario's Grade 9 course, Healthy Active Living Education (PPL1O, 2015 curriculum). It follows the curriculum's wording, uses correct terms and stays factual; it does not describe how to do sexual activities. Families who have concerns about this part of the course can talk to the school about its policy and options. At home, you may choose to read it together, add your family's values, or teach the topic in your own way.

Big idea: C1.4: describe the relative effectiveness of various methods of preventing unintended pregnancy or sexually transmitted infections, including HIV/AIDS, and identify sources of information and support. The lesson states clearly that abstinence is the only 100% effective method and that choosing to wait is common.

Facts used: approximate typical-use effectiveness figures published by public health agencies (e.g. the U.S. Centers for Disease Control and Prevention): IUD over 99%, injection about 96%, pill/patch/ring about 93%, external condom about 87%, internal condom about 79%, withdrawal about 80%. Emergency contraception pills are sold without a prescription in Canada. Ontario has no minimum age of consent to health treatment (Health Care Consent Act; based on capacity). HPV and hepatitis B vaccines are offered to Grade 7 students in Ontario. No humour block is included.

How to help at home: share your family's values and expectations, and also make sure your teen knows they can ask you (or a doctor) anything. Teens who can talk openly with parents tend to make safer decisions.

Common difficulties: confusing perfect and typical use; thinking hormonal methods protect against STIs; believing they'd know if they had an STI.