(a) Fertility

• Infertility treatments and contraception are based on the biology of fertility.
• Women show cyclical fertility leading to a fertile period.
• Women are only fertile for a few days during each menstrual cycle.
• Men continually produce sperm in their testes so show continuous fertility.
• Identification of the fertile period – a woman’s body temperature rises by around 0·5 °C after ovulation and her cervical mucus becomes thin and watery.

(b) Treatments for infertility (female)

• Ovulation stimulated by drugs that prevent the negative feedback effect of oestrogen on FSH secretion.
• Other ovulatory drugs mimic the action of 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) programmes.

(b) Treatments for infertility (male)

Artificial insemination.

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

Intra-cytoplasmic sperm injection (ICSI).

• If mature sperm are defective or very low in number ICSI can be used — the head of the sperm is drawn into a needle and injected directly into the egg to achieve fertilisation.

Treatments for infertility (IVF and PGD)

In vitro fertilisation (IVF) involves:

• Surgical removal of eggs from ovaries after hormone stimulation.
• The eggs are mixed with sperm in a culture dish.
• The fertilised eggs (zygotes) are incubated until they have formed at least eight cells and are then transferred to the uterus for implantation.

Pre-implantation genetic diagnosis (PGD).

• IVF can be used in conjunction with PGD to identify single gene disorders and chromosomal abnormalities.

(c) Contraception

• Physical methods such as
  • barrier methods,
  • intra uterine (inside uterus) devices
  • sterilisation procedures
• The oral contraceptive pill is a chemical method of contraception.
• It contains a combination of synthetic oestrogen and progesterone that mimics negative feedback preventing the release of FSH and LH from the pituitary gland.
• The progesterone-only (mini) pill causes thickening of the cervical mucus.
• Emergency hormonal contraceptive pills, like the ‘morning after pill’, prevent or delay ovulation.