💉 Step 1: give hormones
The mother is given FSH and LH. These stimulate the maturation of several eggs, not just one.
Hormonal Coordination in Humans » Hormones and Infertility Treatment
What you'll learn this session
Study time: 30 minutes
AQA spec: 4.5.3.6 (Higher tier only)
- How FSH and LH can be given as a fertility drug
- The steps of IVF treatment
- The drawbacks of fertility treatment
- The social and ethical issues, and how microscopes made IVF possible
Higher tier only
This whole lesson is for students sitting the Higher tier paper.
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Unlock This CourseWhy do some couples need help?
Some women find it hard to become pregnant. This is called infertility. You already know that FSH and LH control the maturing and release of an egg. Doctors can use hormones as a medicine, so that a woman has a chance to have a baby of her own.
Key terms:
- Infertility: not being able to become pregnant in the normal way.
- Fertility drug: a medicine containing FSH and LH that helps eggs to mature.
- IVF (in vitro fertilisation): a treatment where eggs are fertilised by sperm in a laboratory, outside the body.
- Embryo: a tiny ball of cells formed from a fertilised egg as it begins to develop.
Treatment 1: a fertility drug
The simplest treatment is to give a woman FSH and LH in a fertility drug. The extra hormones help her eggs to mature. She may then become pregnant in the normal way. This means the egg is fertilised inside her body, with no laboratory involved.
Treatment 2: IVF
If a fertility drug is not enough, doctors can use in vitro fertilisation. "In vitro" means "in glass", because the eggs are fertilised in the laboratory and not inside the body. IVF has four main steps.
🧪 Step 2: collect and fertilise
The eggs are collected from the mother. They are fertilised by sperm from the father in the laboratory.
🌱 Step 3: embryos develop
The fertilised eggs develop into embryos.
✅ Step 4: insert
When the embryos are tiny balls of cells, one or two are inserted into the mother's uterus (womb).
Notice why Step 1 uses hormones. Giving FSH and LH means that several eggs mature, so there are more eggs to collect and a better chance that at least one will be fertilised and develop.
Worked example
Put the IVF steps in order: (A) embryos inserted into the uterus, (B) eggs collected and fertilised with sperm, (C) mother given FSH and LH, (D) fertilised eggs develop into embryos.
Answer: C, B, D, A. The hormones come first so that eggs are ready to collect. Insertion comes last, once the embryos are tiny balls of cells.
Microscopes made IVF possible
IVF depends on working with eggs, sperm and very young embryos, which are far too small to see clearly with the eye alone. Developments in microscopy techniques have allowed doctors and scientists to see them in detail. Without these developments, IVF treatments could not have been developed.
The drawbacks of fertility treatment
Fertility treatment gives a woman the chance to have a baby of her own, but it has drawbacks:
😥 Stressful
It is very emotionally and physically stressful.
📉 Low success
The success rates are not high. Many couples go through the treatment and do not have a baby.
👶 Multiple births
It can lead to multiple births (twins or more). These are a risk to both the babies and the mother.
Multiple births can happen when more than one embryo is inserted into the uterus.
Social and ethical issues
You need to understand the social and ethical issues, and be able to look at IVF from the point of view of a patient. Science can tell us how IVF works, but people also have to decide whether it is right.
- In favour: it gives people who could not otherwise have a child the chance to become parents.
- Against: the treatment is stressful, often does not work, and multiple births put babies and the mother at risk.
- Questions people raise: several embryos may be made, so what should happen to the ones that are not used? Who should be offered the treatment?
Different people reach different conclusions, depending on their own beliefs and circumstances. For a patient, the decision means weighing a chance of a baby against the stress, the low success rate and the risks.
Common mistakes
Writing that IVF only needs FSH. It uses FSH and LH. Another slip is saying fertilisation happens inside the mother in IVF. It happens in the laboratory, and the embryos are put into the uterus afterwards. Finally, a fertility drug on its own is not IVF: the woman becomes pregnant in the normal way.
Exam-style question
(a) Describe how IVF is used to treat infertility. [4 marks]
(b) Give two drawbacks of IVF treatment for a woman. [2 marks]
(c) Describe one risk of multiple births. [1 mark]
Model answer
(a) The mother is given FSH and LH (1) to make several eggs mature (1). The eggs are collected and fertilised by sperm in the laboratory (1). The fertilised eggs develop into embryos, and one or two tiny balls of cells are put into the uterus (1).
(b) Any two from: it is very emotionally and physically stressful (1); the success rates are not high (1); it can lead to multiple births, which are a risk to the mother and the babies (1).
(c) They are a risk to the babies and the mother (1).
Exam tip
In a "describe IVF" question, write the steps in order and name both hormones. Each step is usually worth one mark.