My Biology Notebook

Contraception


Previous Topic Next Topic

Contraception 


Non-Hormonal


Surgery:

- Surgically cutting and sealing oviducts/sperm ducts is an extremely effective procedure.
- It is irreversible.


Condoms:

- Rolling a rubber tube over the penis or inserting it into the vagina creates a physical barrier to sperm.
- When used correctly, it proves to be highly effective in preventing infection from most STIs.
- May slip off; must withdraw raw after ejaculation.


Diaphragm:

- A latex or silicone device placed over the cervix to block sperm from entering the uterus. 
- Reusable and cheap, with no health risks.
- Use this product in conjunction with spermicide cream and leave it on for a few hours after sexual activity.


Spermicidal Cream:

- It is toxic to sperm and should not be used alone.
- It enhances the effectiveness of other contraceptive methods.
- Can cause allergies.


Hormonal


Combined Pill:

- Take oestrogen and progesterone daily for 21 days, followed by a 7-day break.
- When taken correctly, it can be very effective in reducing the risk of certain cancers.
- Sickness or taking the pill can have an impact. The risk of blood clots and breast/cervical cancer can escalate significantly.


POP:

- Women who don't suit the combined pill, are older, or have high blood pressure should take progesterone every day at the same time.
- When taken correctly, it can be very effective in reducing the risks of certain cancers.
- Neglecting to take a pill can have an impact.


IUDs:

- Inserted into the uterus, it prevents implantation and releases progesterone. The copper coil is toxic to sperm.
- Lasts over 3 years.
- An uncomfortable surgical insertion procedure may result in longer or more painful periods.


Injections:

- It releases progesterone and lasts for several months.
- Reliable
- Fertility may not return straight after the effective time frame.


Implants:

- Releases progesterone slowly.
- Long-lasting and reliable.
- The procedure is invasive and visible beneath the skin.

- The pills inhibit the release of the pituitary hormones that control egg maturation and release. They also thicken cervical mucus, helping to prevent sperm from reaching the egg.

- Researchers have also developed a micro-implant that can store and release regular, controlled doses of a contraceptive for up to 16 years. You can control it wirelessly and turn it off at any time to start a family.


Natural Planning Methods:

- You have to know your body very well.
- Avoid having sex when an egg is likely to be in the ovary.
- A woman's "fertile time," or ovulation, is linked with:
→ Her menstrual cycle is ≈ 14 days.
→ A slight increase in body temperature.
→ The mucus secreted from the cervix is thinning.
- By estimating when ovulation occurs, it's possible to avoid having sex when eggs are in the oviduct. 


Factors:

Consider the following factors when deciding on the type of contraception to use:
- They can afford to start a family.
- How long-lasting the contraception is.
- How quickly reversible contraception is.
- How soon the woman wants to be pregnant after contraception. 
- Religious/ethical factors.


Fertility and IVF


Infertility:

- When a couple cannot get pregnant.
- As a woman gets older, fertility levels begin to decrease; therefore, the quality of the egg cell decreases.
- Even healthy young couples can have fertility problems.
- The NHS recommends fertility investigations for those who have been trying to conceive for a year, or six months for women over 35.


Fertility Drug:

- Injection of FSH and LH. This helps treat infertility.
→ Common problem: Women aren't ovulating.
→ Give FSH + LH to stimulate ovaries.
→ Women given this are warned of the possibility of multiple births.

- 'In vitro' fertilisation, also known as IVF, occurs outside the body.
→ Very expensive but now very common.


Procedure:

1. Reproductive hormones stimulate the ovaries.
2. The woman's ovaries produce the eggs.
3. A petri dish contains a mixture of eggs and sperm.
4. Fertilisation happens in the dish.
5. Choose one or two tiny embryos.
6. The uterus receives the embryo, where it may implant normally.

- IVF success rates are, on average, 20-25%.
- A person who is younger, has previously given birth, has a BMI between 19 and 30, does not smoke, and consumes little alcohol or caffeine is more likely to succeed.
- Couples are offered counselling before and during IVF: the aim is to be optimistic yet prepared for failure. 


Disadvantages:

- Stressful, not very successful yet, very expensive, and emotionally and physically invasive for women. 
- This raises ethical concerns: can we screen embryos without transplants for genetic defects to create designer babies?

Previous Topic Next Topic