Reproductive biology 1/ Reproductive organs and hormonal control 2/ The biology of fertility control 3/ Ante-natal and post-natal screening

The biology of fertility control -The biology of controlling fertility. -Contraception -Treatments for infertility -Risks and ethics associated with fertility treatments.

What fundamental difference is there between the fertility of men and women? Males are continuously fertile due to relatively constant levels of pituitary hormones. Females’ fertility is cyclical, usually restricted to 1-2 days immediately following ovulation.

What are the three ways of predicting ovulation in women? The time of ovulation can be estimated by - the number of days after menstruation - a slight rise in body temperature on the day of ovulation - the thinning of the cervical mucus.

What is fertilisation? Where does it take place? Fertilisation is the fusion of the male and female gametes which creates the zygote. it takes place in the oviduct.

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At which stage of embryo development does implantation take place? The developing embryo implants (i.e. adheres to and grows into the wall of the uterus) at the blastocyst stage (6-12 days old embryo). fsRU fsRU

Recap of learning outcomes The biology of controlling fertility. -Males are continuously fertile due to relatively constant levels of pituitary hormones. -Females’ fertility is cyclical, usually restricted to 1-2 days immediately following ovulation.

-The time of ovulation can be estimated by 3 indicators - the number of days after menstruation - a slight rise in body temperature on the day of ovulation -the thinning of the cervical mucus.

-Fertilisation (i.e. the fusion of the male and female gametes) which creates the zygote takes place in the oviduct. - The developing embryo implants (i.e. adheres to and grows into the wall of the uterus) at the blastocyst stage (6-12 days old embryo).

The biology of fertility control -The biology of controlling fertility. -Contraception

What are the two approaches to contraception? Physical and chemical methods What do physical methods encompass? all attempts to: – block the ability of sperm to reach the ova – prevent implantation from taking place.

Examples of devices acting as a barrier to block the ability of sperm to reach the ova? Condom Diaphragm Cervical cap Can be left for a few days

What is the medical name of the “coil” and how does it work – Intra Uterine Device (IUD) – To interfere with sperm viability and implantation

How can fertile periods be avoided? Good luck….

Sterilisation

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Which two types of oral contraception (i.e. taken in the form of a pill) are considered as physical barriers? ‘morning-after pills’ : prevents implantation ‘progesterone- only pill’: causes the thickening of cervical mucus

Chemical methods: contraceptives How do they work? Chemical contraceptives are based on combinations of synthetic hormones that mimic negative feedback preventing the release of FSH/LH.

Recap of learning outcomes Physical methods: they encompass all attempts to block the ability of sperm to reach the ova or attempts to prevent implantation from taking place. Using a device as a barrier to block the ability of sperm to reach the ova: condom, diaphragm, cervical cap, To interfere with sperm viability and implantation: intra uterine device (IUD) Avoiding fertile periods. Sterilisation Some prevent implantation (‘morning-after pills’) Some cause the thickening of cervical mucus (‘progesterone- only pill’).

Chemical methods: contraceptives – Chemical contraceptives are based on combinations of synthetic hormones that mimic negative feedback preventing the release of FSH/LH.

The biology of fertility control -The biology of controlling fertility. -Contraception -Treatments for infertility -Risks and ethics associated with fertility treatments.

Treatments for infertility (3 types) Treatments which stimulates ovulation Artificial insemination In vitro fertilisation

Treatments which stimulates ovulation Female infertility may be due to failure to ovulate. -What are the most common causes of failure to ovulate? -stress, weight fluctuations and Polycystic Ovarian Syndrome (PCOS).

Treatments which stimulates ovulation -Could you suggest how ovulation could be stimulated? Treatment with drugs which -mimic FSH and LH -prevent the negative feedback effect of oestrogen on FSH secretion. This will stimulate ovulation

Treatments which stimulates ovulation What is often the outcome of stimulated ovulation? Super ovulation. What is a likely consequence of super ovulation? Multiple births For what else is super ovulation useful? To collect ova for in vitro fertilisation (IVF) programmes.

Recap of learning outcomes Treatments which stimulate ovulation Failure to ovulate can be treated with drugs which mimic FSH and LH These drugs can cause super ovulation that can result in multiple births or be used to collect ova for in vitro fertilisation (IVF) programs. Drugs can also be given to prevent the negative feedback effect of oestrogen on FSH secretion. This will stimulate ovulation.

Treatments for fertility (3) Treatments which stimulates ovulation Artificial insemination

When is artificial insemination the right choice of treatment? Artificial insemination is particularly useful where the male has a low sperm count. How is the semen collected? Several samples of semen are collected over a period of time. What can be done if a partner is sterile? If a partner is sterile a donor may be used.

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Recap of learning outcomes Artificial insemination Artificial insemination is particularly useful where the male has a low sperm count. Several samples of semen are collected over a period of time. If a partner is sterile a donor may be used.

Treatments for fertility Treatments which stimulates ovulation Artificial insemination In vitro fertilisation

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What does IVF stand for? In Vitro Fertilisation (IVF) What are the first 2 steps of IVF (for the female only) Stimulation of ovaries by hormones The ova are surgically removed from the ovaries What is then happening outside of the female body? The ova are then mixed with sperm in a culture dish outside the female’s body. Mixture incubated until ready to be transferred At which stage are the embryo transferred to the uterus for implantation? When they have formed at least 8 cells and are then transferred to the uterus for implantation.

What does ICSI stand for? IntraCytoplasmic Sperm Injection When is it useful? During IVF if mature sperm are defective or very low in number. Describe the technique. The head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.

What is done in conjunction with IVF? Pre-implantation Genetic Diagnosis (PGD) NyI NyI What sort of problems is PGD able to identify? Single gene disorders and chromosomal abnormalities.

Recap of learning outcomes In vitro fertilisation In vitro fertilisation (IVF) is when ova are surgically removed from the ovaries after stimulation by hormones. The ova are then mixed with sperm in a culture dish outside the female’s body. The fertilised eggs are incubated until they have formed at least 8 cells and are then transferred to the uterus for implantation. Intracytoplasmic sperm injection (ICSI) can be used during IVF if mature sperm are defective or very low in number. The head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.

The biology of fertility control -The biology of controlling fertility. -Contraception -Treatments for infertility -Risks and ethics associated with fertility treatments.

Risks and ethics associated with fertility treatments. Some people support PGD as it offers reassurance to couples who are at high risk of having a child with a genetic disease. Some of these people would choose to remain childless without the help of PGD. Supporters claim that a reduced frequency of genetic diseases and disorders is of great benefit to society as a whole. People opposed to PGD claim that it is morally wrong to interfere with conception. They argue that these procedures are the start of eugenics-selective breeding in humans- and lead to designer babies