Contraception
Laura Armstrong
Teacher
Contents
Recall Questions
This topic requires prior knowledge of hormones that regulate the menstrual cycle.
Which hormone causes an egg cell to mature in the ovaries?
FSH (Follicle-Stimulating Hormone).
What is ovulation and when does it occur?
Ovulation is the release of an egg from the ovary, usually around day 14 of the menstrual cycle.
What does progesterone do in the menstrual cycle?
Maintains the uterus lining and inhibits the release of FSH and LH.
Topic Explainer Video
Check out this @lauradoesbiology video that explains contraception, then read the study notes. Once you’ve gone through them, don’t forget to try the practice questions!
Contraception
What is Contraception?
Contraception is the use of methods or devices to prevent pregnancy. It works by:
- Stopping the release of an egg from the ovaries.
- Preventing sperm from reaching the egg so fertilisation does not occur.
- Stopping fertilised eggs from implanting in the uterus.
Hormonal Methods of Contraception
|
Method |
How it Works |
Pros |
Cons |
|
Combined Pill |
Contains oestrogen + progesterone. Inhibits FSH and LH, so no egg matures and ovulation does not occur. |
Highly effective if used correctly. Regulates periods. |
Must be taken daily, so may be forgotten. Side effects (nausea, mood swings). No STI protection. |
|
Mini Pill (Progesterone-only pill) |
Contains progesterone only. Thickens cervical mucus and prevents ovulation (as it inhibits FSH and LH). |
Good for women who can't take oestrogen. Fewer side effects than the combined pill. |
Must be taken every day. Less effective than the combined pill as it does not contain oestrogen. No STI protection. |
|
Injection |
Contains progesterone. Stops ovulation and thickens cervical mucus. |
Lasts 8–13 weeks. No daily pill to remember! |
No STI protection. Side effects. Delay in return to fertility. |
|
Implant |
Slowly releases progesterone. Prevents ovulation and thickens mucus. |
Lasts up to 3 years. Very effective. |
Minor surgical procedure which may be uncomfortable. No STI protection. Delay in return to fertility. |
|
Patch |
Sticks to skin and releases oestrogen and progesterone. Works like the combined pill. |
Easy to use weekly. Doesn’t involve remembering a daily pill. |
Can cause skin irritation. It only lasts for 7 days so need to remember to replace it. |
|
Hormonal Coil |
Releases progesterone. Thickens mucus and prevents implantation. |
Lasts 3–5 years. Lighter periods. Very effective. |
Insertion can be uncomfortable. No STI protection. Will need to have it removed and wait for fertility to return if the woman wants a baby. |
Non-Hormonal Methods of Contraception
|
Method |
Type of contraception |
How it works |
Pros |
Cons |
|
Condoms (male/female) |
Barrier method |
Prevent sperm reaching the egg, so no fertilisation can occur. |
Protects against STIs. Easy to use. |
Can split or slip. Must be used correctly every time to be effective. |
|
Diaphragm + Spermicide |
Barrier method |
Sits over the cervix. Prevents sperm entering the uterus. Used with spermicide to kill sperm. |
Reusable. No side effects. |
Less effective than condoms. Must be fitted correctly. |
|
Spermicides |
Chemical method |
Kills sperm. Used alongside other methods. |
Easy to use with barrier methods. |
Not effective alone. Can cause irritation. |
|
Copper Coil |
Non-hormonal |
Copper is toxic to sperm and egg; prevents fertilisation and implantation. |
Lasts 5–10 years. Hormone-free. |
Can cause heavier periods and cramps. No STI protection. Needs to be removed by a professional. |
|
Abstinence |
Natural method |
Avoid intercourse during fertile window. |
No side effects. Free. |
Unreliable without careful tracking. No STI protection. |
|
Sterilisation |
Surgical method |
Cuts sperm ducts or oviducts. Prevents sperm/egg meeting. |
Permanent. No daily effort. |
Irreversible. Involves surgery which has risks. No STI protection. |
Key Terms
- FSH: Stimulates egg maturation - hormonal contraceptives block this hormone.
- LH: Stimulates ovulation - hormonal contraceptives block this hormone.
- Ovulation: Release of an egg - hormonal contraception prevents this.
- Barrier method: Prevents sperm reaching the egg.
- Contraception: is the use of methods or devices to prevent pregnancy.
No answer provided.
Exam Tip
In evaluation questions, give advantages and disadvantages. If they provide you with information about contraceptives, use the information in your answers, but add your own knowledge too!
No answer provided.
Practice Questions
Question: The table shows some information about three methods of contraception.
|
Method |
Effectiveness |
Other information |
|
Combined pill |
99.5% |
• Must be taken every day • Free from your GP or sexual health clinic • May cause headaches |
|
Male condom |
98.0% |
• May split or leak • Only used when you have sexual intercourse • Inexpensive in supermarkets or free from a sexual health clinic |
|
Sterilisation |
100.0% |
• Needs an operation in hospital • Usually cannot be reversed |
A man and a woman plan to start a family in 5 years’ time.
Compare the risks and benefits for this couple of the three methods of contraception. (6 marks)
Model Answer
With advantages and disadvantages (A and D):
Combined Pill
• A – easy to take, very effective and free on NHS.
• D – it can cause headaches/side effects, must remember to take it every day.
Condom
• A – only need it when you have sex, no side effects, very inexpensive.
• D – it is not as reliable, more difficult to use.
Sterilisation
• A – 100% effective.
• D – probably will not be able to have a family as it cannot usually be reversed, risks of surgery.
More Practice
Try to answer these practice questions from the TikTok videos on your own, then watch the videos to see how well you did!