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Human
sexual reproduction:
Part 7.
Treating infertility
- methods of increasing fertility, increasing chance of pregnancy,
hormone treatment, IVF, insemination
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Sub-index of biology notes on human sexual reproduction
(7) Methods of increasing fertility
- increasing the chance of pregnancy
How can hormones be used to control fertility?
In this case for conception purposes.
How does In Vitro Fertilisation' (IVF) work?
This is page
is all about the complete opposite of
contraception!
The desire for children is a very powerful motivation in
human nature but to be infertile means you cannot reproduce naturally.
Unfortunately some women are infertile,
unable to get pregnant and reproduce naturally, but, help is at
hand from various hormonal treatments to greatly improve their fertility
and ultimately deliver a baby.
Hormones are a key factor in
fertility, and can be used to increase fertility - to increase the
chance of pregnancy.
Using hormones to increase fertility
Some women have too low a
level of FSH (follicle-stimulating hormone) to stimulate the
eggs to mature in the ovary. Therefore no ovulation, no eggs are released and
pregnancy cannot happen.
FSH and LH (luteinising hormone)
can be administered as a fertility drug to stimulate
ovulation.
The method obviously improves
fertility - the chances of getting pregnant, but there are
'negatives'.
(i) The treatment is
expensive and doesn't always work.
(ii) Sometimes too many eggs
are stimulated at the same time resulting in multiple
pregnancies e.g. twins or triplets.
Women can be infertile due to
lack of ovulation (none or irregular ovulation), so another
similar approach is to use the medication clomifene therapy
(clomiphene).
Clomifene (clomiphene) works by causing
more FSH and LH to be released by the body - this in turn
stimulates eggs to mature and be released (ovulation).
If you know when the woman is
more likely to ovulate, a couple can have intercourse during
the treatment period to increase the chances of the woman
becoming pregnant.
However, there are some
unpleasant side effects from using clomifene e.g. pelvic pain
and hot flushes.
IVF treatment - In Vitro
Fertilisation
What is IVF?
IVF stands for 'In Vitro Fertilisation',
is an option for treating infertility in which eggs are
fertilised outside the woman's body by sperm from the father.
Why choice of IVF?
Sometimes giving FSH and LH in a ‘fertility drug’ to a woman
whose own level of FSH is too low to stimulate
eggs to mature doesn't always work.
If women are unable to get
pregnant with hormonal treatment they may try IVF treatment.
IVF is an example of
Assisted Reproductive Technology (ART), defined as a
fertility treatment involving the handling of eggs (usually
fertilised) outside of the body.
The IVF procedure
IVF involves giving a mother
FSH and LH to stimulate the maturation of several eggs where they would not have been released
- this must be done before egg collection, and it also means
more than one egg can be collected.
In IVF treatment, after the
potential mother has been treated with FSH and LH, eggs are collected from
her ovaries and
fertilised in the laboratory by sperm from the father.
The mixture is monitored
microscopically, over a period of 16-20 hours, to look for
successful fertilisation.
IVF treatment can also
involve a technique called Intra-Cytoplasmic Sperm Injection
(ICSI), where the sperm is directly injected into an
egg.
This may be applied if the sperm count of the man is
low.
In either case, in a laboratory,
the fertilised
eggs grow and develop into embryos in a incubator.
At the stage when
the fertilised eggs are just tiny balls of cells (~100), one or two embryos
are inserted into the mother’s uterus (womb) to attempt a pregnancy.
The initial success rate is
not that high, 20-30% of each cycle of treatment
The chance of pregnancy
decreases with each successive round and the cost increases too.
However, the cumulative
effect of three full cycles of IVF treatment can give an over
45% chance of pregnancy.
IVF techniques are more
successful if the woman has (i) been pregnant before, (ii)
younger, (ii) has a BMI of between 10 and 30, (iv) has a low
alcohol and caffeine intake and doesn't smoke.
Advantages and disadvantages
of IVF treatment - the 'pros and cons'
Some women, for various
medical reasons, cannot conceive in the conventional way.
BUT, IVF has enabled many mothers to
get pregnant and give birth to healthy children - a wonderful application of
medical science and technology.
BUT it doesn't always work
for an infertile couple and there other downsides too.
About half of the embryos
produced by IVF have an incorrect number of chromosomes -
genetically defective.
Also, about 1/3rd of the
normal embryos selected, will not implant in the uterus.
Sadly, tragically, there
are raised incidences of premature births, stillbirths, low
birth-weights and infant deaths.
It is possible for several
eggs to be simultaneously matured resulting in multiple pregnancies eg
twins, triplets and more develop from the growth of more than one embryo
into a baby!
This increases the risk
for mother and babies - multiple pregnancy puts extra strain
on the mother - there is an increased risk of an
unsuccessful birth e.g. miscarriage or stillbirth.
IVF has a low success
rate, averaging 26% in the UK. It ranges from 29% for women
under 35, down to 23% or less for women over 35. Age is an
important factor and fertility decreases as a woman gets
older.
This low success rate
makes the whole process very stressful both physically
and mentally - the situation is emotionally draining,
especially if IVF treatment fails several times.
Women can suffer side-effects
from the hormone treatment which can be physically and emotionally
demanding e.g. abdominal pain, dehydration, vomiting - an overlap of side
effect symptoms from hormonal contraception
BUT, most infertile couples would regard IVF treatment is worth
the risk.
Advances in IVF techniques
Microscope techniques
have become more advanced and improved the success rate of
IVF fertility treatment.
This involves using
special micro-tools to manipulate sperm and eggs under the
microscope.
You can now remove single
cells from the embryo for genetic testing to check if the
genome will facilitate a healthy embryo-baby.
With a microscope and
camera, you can also use time lapse imaging of the embryo
growing in the incubator, allowing you to continuously
monitor the growth of the embryos to see which are the most
likely to result in a successful pregnancy
Objections to IVF treatments -
ethical issues
Most objections centre around
the ethical issues of IVF.
(i) IVF procedures often
result in unused embryos being destroyed and some people
consider this unethical - immoral, because you have destroyed a
potential human life.
Is right that the bundle
of cells of the embryo are arbitrarily used or discarded?
and destroyed.
Are the inevitable losses
of potential life, albeit genetically defective, worth the
price of successfully developed embryos?
(ii) The
genetics and genetic testing of
embryos before implantation in the mother's womb raises the
ethical issue of preferential choice of characteristics of the
baby e.g. choice of gender, eye colour or even whether you allow
a child to be born with disabilities.
With advances in
microscopic and genetic techniques it is possible to screen
the embryos for abnormalities e.g. genetic defects, this
means we are making a life or death decision on the test
outcome.
Couples, where one is a
normal fertile women, could use IVF to select, and allow/not
allow to develop, a child with particular characteristics
e.g. sex. Many would regards this as unethical and a misuse
of IVF.
(iii) Some people consider
that IVF as just getting round natural obstacles to getting
pregnant
But IVF is not natural,
and some consider it unnatural, because it replaces the
physical and emotional relationship of conceiving by
intercourse with a 'synthetic' laboratory technique.
Evaluation of IVF
You might be expected to evaluate the benefits of, and the problems that may
arise from, the use of hormones to control fertility,
including In Vitro Fertilisation (IVF)
and might be given information data to work on.
Artificial insemination (AI)
AI, also known as intrauterine insemination
(IUI), is a fertility treatment that involves directly
inserting sperm into the woman's womb.
You need a sperm donor, a 'partner' (known
father) or frozen sperm from a sperm bank (anonymous father)..
Key points
about fertility treatments
Source of information is based on textbooks & syllabus-specifications for students taking the AQA
GCSE, Edexcel GCSE and OCR
GCSE level biology examinations (~US grades 9-10).
Revision notes for biology students on methods
of increasing fertility, including hormone treatments,
IVF, artificial insemination, and
their advantages and disadvantages.
What Is Infertility?
Infertility is when a couple cannot
conceive naturally after regular unprotected sex. It can be caused by:
-
Low levels of reproductive hormones
(e.g. FSH or LH)
-
Blocked fallopian tubes
-
Poor sperm quality or low sperm count
-
Age-related decline in fertility
Hormone Treatments (Fertility Drugs)
Hormones Used:
How It Works:
Advantages:
Disadvantages:
In Vitro Fertilisation (IVF)
What Is IVF?
IVF is fertilisation that occurs
outside the body in a lab.
Steps:
-
Woman is given FSH and LH to stimulate
egg production.
-
Eggs are collected from the ovaries.
-
Eggs are fertilised with sperm in a lab
dish.
-
Embryos develop for a few days.
-
1 or 2 embryos are implanted into the
uterus.
Advantages:
-
Helps couples with blocked tubes or
low sperm count.
-
Can use donor eggs or sperm.
-
Embryos can be screened for genetic diseases.
Disadvantages:
-
Expensive and not always available on
the NHS.
-
Low success rate, especially in older
women.
-
Risk of multiple births and
side effects from hormone drugs.
-
Ethical concerns about unused embryos.
Artificial Insemination (AI)
What Is It? Sperm is inserted directly into the uterus or cervix
using a syringe.
When Is It Used?
Advantages:
Disadvantages:
Comparing Fertility Treatments
|
Method |
How It Works |
Advantages |
Disadvantages |
|
Hormone Therapy |
Stimulates ovulation using FSH & LH |
Simple, non-invasive |
May not work; risk of multiple births |
|
IVF |
Fertilisation outside the body |
Helps with severe infertility; embryo screening |
Expensive; emotional stress; ethical concerns |
|
AI |
Sperm inserted into uterus |
Less invasive; useful with donor sperm |
Lower success rate; may need repetition |
Why This Is Important in Human Biology
-
Demonstrates how hormones regulate reproduction.
-
Shows how medical science can support
fertility.
-
Encourages understanding of ethical, social, and
economic issues.
-
Reinforces knowledge of homeostasis,
hormonal control, and reproductive systems.
Exam Tips
-
Use key terms: FSH, LH,
ovulation, IVF, insemination,
fertility drugs, embryo.
-
Be able to describe and evaluate each
method.
-
Understand the advantages and disadvantages
from both medical and ethical perspectives.
Keywords, phrases and learning objectives for this part on ways of increasing
fertility
Be able to describe and discuss how methods of
increasing fertility to increase the chance of pregnancy work,
including IVF In Vitro Fertilisation procedure, FSH and LH hormone
treatment, artificial insemination, which may involve embryo
selection.
Be able to describe the advantages and disadvantages
of these 'fertility' procedures and their relative success rate.
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igcse/gcse biology notes on methods of treating infertility, Edexcel gcse
biology notes on methods of treating infertility, OCR 21st century GCSE
biology notes on methods of treating infertility, OCR gateway
GCSE biology notes on methods of treating infertility, WJEC gcse biology notes on
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insemination
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insemination
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IVF & artificial insemination when studying GCSE level biology, exam revision
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treating infertility, hormone treatment, IVF & artificial insemination in GCSE
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hormone treatment, IVF & artificial insemination? what do I need to know about
methods of treating infertility, hormone treatment, IVF & artificial
insemination for GCSE biology exams, how to prepare for questions on
methods of treating infertility, hormone treatment, IVF & artificial
insemination in GCSE
biology examination? methods of treating infertility, hormone treatment,
IVF & artificial insemination for
syllabus-specifications
for students taking the IGCSE/GCSE level biology examinations, summary
revision notes key points on methods of treating infertility, hormone
treatment, IVF & artificial insemination for students studying AQA
igcse/gcse biology notes on methods of treating infertility, hormone treatment,
IVF & artificial insemination, Edexcel gcse
biology notes on methods of treating infertility, hormone treatment,
IVF & artificial insemination, OCR 21st century GCSE
biology notes on methods of treating infertility, hormone treatment,
IVF & artificial insemination, OCR gateway
GCSE biology notes on methods of treating infertility, hormone
treatment, IVF & artificial insemination, WJEC gcse biology notes on
methods of treating infertility, hormone treatment, IVF & artificial
insemination, CCEA
gcse biology notes on methods of treating infertility, hormone
treatment, IVF & artificial insemination, CIE Cambridge igcse
biology, notes on
methods of treating infertility, hormone treatment, IVF & artificial
insemination useful for US grade 9-10 biology student courses
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