Contraceptives
Fertility is the natural, physical capability to conceive a child and produce offspring.
Fertility can be controlled using hormonal and non-hormonal contraception.
Hormonal methods
Oral contraceptive pill
This pill contains hormones (usually oestrogen + progesterone or progesterone only).
The pill prevents FSH being released, so the egg doesn’t mature and ovulation doesn’t happen.
The contraceptive pill mainly prevents pregnancy by stopping ovulation, and it also thickens cervical mucus to make it harder for sperm to reach an egg and thins the uterus lining to make implantation less likely.
Progesterone only, long term methods
These long term options include injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years.
Hormone-releasing IUD (hormonal coil)
It releases progesterone which prevents pregnancy by making it difficult for sperm to reach the egg and making the uterus lining thinner so implantation is less likely.
The presence of the IUD device itself also makes implantation less likely.
Non-Hormonal Methods
Barrier methods
Examples include condoms and diaphragms. These physically stop sperm reaching egg.
An advantage of this method over other is that condoms also reduce STI transmission between an infected individual an uninfected individual.
Non hormonal IUD
This is a copper coil that is placed in the uterus. In this case it does not release hormones.
It prevents pregnancy by making it harder for sperm to survive / move due to slowly releasing copper ions.
Also makes implantation less likely due to the structure of the coil.
Spermicides
Spermicides are chemicals that kill or disable sperm. They are not entirely effective on their own, so they need to be combined with barrier methods, such as condoms.
Natural method (fertility awareness / abstaining at fertile time)
This methods works by avoiding intercourse when egg likely present in oviduct.
It is only completely successful if intercourse is permanently avoided.
If intercourse is only partially avoided it not very reliable.
Sterilisation
This is a more permanent method of contraception.
In males the vas deferens cut. This is the tube that carries the sperm from the testes.
In females the oviducts are blocked or cut. This prevents the egg reaching the uterus.
In both cases pregnancy is prevented because sperm and egg cannot meet.
Evaluating Contraception Methods
Reliability – How effective is the method at preventing pregnancy?
Example: The pill is very reliable if taken correctly, condoms are fairly reliable, and natural methods like fertility awareness are less reliable.
Protection from STIs – Does the method reduce the risk of sexually transmitted infections?
Example: Only condoms provide protection against STIs.
Side effects – Are there any health effects to consider?
Example: Hormonal methods like the pill or implant can cause side effects such as mood changes or nausea.
Permanence – Is the method temporary or permanent?
Example: Sterilisation is permanent, while pills, condoms, or implants are temporary.
Ease of use – How easy is the method to use correctly?
Example: Taking a pill every day requires more effort than having an implant or using a condom.
Why Contraception Issues Aren’t Just Science
Science can tell us how contraception works and how effective different methods are, but it cannot answer all questions about contraception. This is because:
People have different personal or religious beliefs about contraception.
Contraception decisions often involve ethical or cultural choices, not just biological facts.
Access to contraception can be affected by social or economic factors.
Deciding whether or which contraception to use involves personal, social, and moral considerations.
Everyday and Technological Applications
Science has many applications in daily life and technology.
Science is used in everyday life or in new technologies.
Example: Hormonal contraceptives are a technological application of biology.
Evaluate(advantages and disadvantages) implications of these applications:
Personal: How it affects individuals’ health and choices
Social: Impact on society and relationships
Economic: Costs and access
Environmental: Any effects on the environment (e.g., disposal of medical devices)
Make decisions based on evidence and arguments.
In contraception, this means weighing scientific evidence about effectiveness and safety alongside social, economic, and ethical considerations before deciding what’s best.
Practice Questions
1.Explain how the oral contraceptive pill prevents pregnancy.
2.A couple want contraception that is temporary, reliable, and protects against STIs. Which method(s) would you recommend and why?
3.Compare hormonal and non-hormonal contraception methods in terms of reliability, side effects, permanence, and protection against STIs.
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