GCSE Biology revision

Contraception

Hormonal coordination in humans

AQA 4.1.1.1

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AQA student objectives

Learning pathway

All · Most · Some

ALL 🎯

Identify and describe How Pregnancy Begins, Hormonal Contraception: How It Works and The Contraceptive Pill in the context of contraception.

MOST 🎯🎯

Explain the relationships between How Pregnancy Begins, Hormonal Contraception: How It Works and The Contraceptive Pill and how they contribute to contraception.

SOME 🎯🎯🎯

Apply and analyse knowledge of How Pregnancy Begins, Hormonal Contraception: How It Works and The Contraceptive Pill to interpret unfamiliar information about contraception.

Revision summary

Key knowledge

Read on screen, then print for Cornell-style active revision.

How Pregnancy Begins

FSH stimulates egg development in the ovaries, and LH triggers ovulation, releasing the egg into the fallopian tube.
If a sperm fertilises the egg in the fallopian tube, the fertilised egg travels to the uterus and implants into the uterine wall to develop into a foetus.
Contraception works by interrupting this process at one or more stages to prevent pregnancy.

1. How Pregnancy BeginsAQA

Notes

FSH stimulates egg development in the ovaries, and LH triggers ovulation, releasing the egg into the fallopian tube.
If a sperm fertilises the egg in the fallopian tube, the fertilised egg travels to the uterus and implants into the uterine wall to develop into a foetus.
Contraception works by interrupting this process at one or more stages to prevent pregnancy.

Hormonal Contraception: How It Works

Oestrogen, when released steadily, inhibits FSH production, preventing egg development and ovulation.
Progesterone stimulates the production of thick mucus in the cervix, blocking sperm from reaching the egg.
Many hormonal contraceptives use a combination of oestrogen and progesterone to provide dual protection against pregnancy.

2. Hormonal Contraception: How It WorksAQA

Notes

Oestrogen, when released steadily, inhibits FSH production, preventing egg development and ovulation.
Progesterone stimulates the production of thick mucus in the cervix, blocking sperm from reaching the egg.
Many hormonal contraceptives use a combination of oestrogen and progesterone to provide dual protection against pregnancy.

The Contraceptive Pill

The combined oral contraceptive pill contains both oestrogen and progesterone and is over 99% effective when taken correctly.
The combined pill can cause side effects such as headaches or nausea in some users.
The progesterone-only pill is equally effective but tends to cause fewer side effects than the combined pill.

3. The Contraceptive PillAQA

Notes

The combined oral contraceptive pill contains both oestrogen and progesterone and is over 99% effective when taken correctly.
The combined pill can cause side effects such as headaches or nausea in some users.
The progesterone-only pill is equally effective but tends to cause fewer side effects than the combined pill.

Hormonal Patches, Injections & Implants

The contraceptive patch is worn on the upper arm, releases oestrogen and progesterone, and each patch lasts one week.
The contraceptive injection delivers progesterone into the upper arm and remains effective for 2 to 3 months per dose.
The contraceptive implant is a small device inserted under the skin of the arm that slowly releases progesterone for up to 3 years.

4. Hormonal Patches, Injections & ImplantsAQA

Notes

The contraceptive patch is worn on the upper arm, releases oestrogen and progesterone, and each patch lasts one week.
The contraceptive injection delivers progesterone into the upper arm and remains effective for 2 to 3 months per dose.
The contraceptive implant is a small device inserted under the skin of the arm that slowly releases progesterone for up to 3 years.

Intrauterine Devices (IUDs)

The plastic IUD is placed inside the uterus and releases progesterone, stimulating thick cervical mucus to block sperm.
The copper IUD (copper coil) is a non-hormonal device that kills sperm inside the uterus, preventing fertilisation.
Both the plastic and copper IUD can last over 3 years, making them long-term contraceptive options.

5. Intrauterine Devices (IUDs)AQA

Notes

The plastic IUD is placed inside the uterus and releases progesterone, stimulating thick cervical mucus to block sperm.
The copper IUD (copper coil) is a non-hormonal device that kills sperm inside the uterus, preventing fertilisation.
Both the plastic and copper IUD can last over 3 years, making them long-term contraceptive options.

Barrier Methods of Contraception

Male condoms are worn over the penis to trap sperm, while female condoms are worn inside the vagina to achieve the same effect.
Condoms are the only form of contraception that also protect against sexually transmitted diseases (STDs).
The diaphragm is a shallow plastic cup placed over the cervix to block sperm from entering the uterus, but must be used alongside spermicide due to its low reliability alone.
Spermicide is a substance that kills sperm but is only effective around 7 out of 10 times when used alone, making it an unreliable sole method.

6. Barrier Methods of ContraceptionAQA

Notes

Male condoms are worn over the penis to trap sperm, while female condoms are worn inside the vagina to achieve the same effect.
Condoms are the only form of contraception that also protect against sexually transmitted diseases (STDs).
The diaphragm is a shallow plastic cup placed over the cervix to block sperm from entering the uterus, but must be used alongside spermicide due to its low reliability alone.
Spermicide is a substance that kills sperm but is only effective around 7 out of 10 times when used alone, making it an unreliable sole method.

Sterilisation

Female sterilisation involves cutting or tying the fallopian tubes, preventing eggs from travelling from the ovaries to the uterus.
Male sterilisation (vasectomy) involves cutting and tying the sperm ducts, preventing sperm from being released during ejaculation.
Sterilisation is considered a permanent procedure and is generally chosen only by those who do not wish to have any more children.

7. SterilisationAQA

Notes

Female sterilisation involves cutting or tying the fallopian tubes, preventing eggs from travelling from the ovaries to the uterus.
Male sterilisation (vasectomy) involves cutting and tying the sperm ducts, preventing sperm from being released during ejaculation.
Sterilisation is considered a permanent procedure and is generally chosen only by those who do not wish to have any more children.

Natural Methods & Abstinence

Natural methods include only having sex at certain times of the month or withdrawing before ejaculation, but both are highly unreliable.
Abstaining from sex altogether is the only method that is 100% effective at preventing pregnancy.

Comparing Contraceptive Methods: Key Considerations

Hormonal methods vary in how invasive they are, ranging from taking a daily pill to having a device implanted under the skin.
The duration of effectiveness varies greatly across methods, from a single day (condom) to several years (IUD or implant).
Choosing a contraceptive method involves weighing up effectiveness, side effects, invasiveness, and duration of protection.

9. Comparing Contraceptive Methods: Key ConsiderationsAQA

Notes

Hormonal methods vary in how invasive they are, ranging from taking a daily pill to having a device implanted under the skin.
The duration of effectiveness varies greatly across methods, from a single day (condom) to several years (IUD or implant).
Choosing a contraceptive method involves weighing up effectiveness, side effects, invasiveness, and duration of protection.