contraception and fertility

• fertility can be controlled by a variety hormonal and non-hormonal methods of contraception
• oral contraceptives : contain hormones than inhibit FSH production so no eggs mature -

  • advantages: 99% effective at preventing pregnancy and progesterone only pill has less side effects
  • disadvantages: only effective if the woman remembers to take it as regularly as necessary, combined pill with oestrogen and progesterone can have strong side effects including mood swigs, depression and increased blood pressure
• injection, implant or skin patch of slow release progesterone to inhibit the maturation and release of eggs for a number of months or years and thickens the mucus in the cervix so sperm cannot swim and fertilised eggs cannot implant into lining:

  • advantages: woman doesn't have to remember to take a pill,
  • disadvantages: will eventually need to be replaced, women might not have access to healthcare that can carry out these procedures
• barrier methods (eg condoms and diaphragms) that prevent sperm from reaching an egg:

  • advantages: prevents pregnancies and transmission of STD's, more widely and readily available
  • disadvantages: can tear and let sperm reach egg, not the most effective method
• spermicidal agents which kill or disable sperm:

  • disadvantage: only 70-80% effective
• intrauterine devices : prevent implantation of an embryo or releasing hormones to prevent pregnancy -

  • copper IUD releases low levels of copper ions which disable sperm cells
  • plastic IUD stimulates the production of progesterone which causes the mucus in the cervix to thicken so sperm cells cannot reach egg cells
• surgical sterilisation : cutting and tying the fallopian tubes or sperm duct -

  • advantage: highly effective
  • disadvantage : method lasts forever
• abstaining from intercourse when an egg may be in the oviduct:

  • advantages: 100% effective during abstinence
  • disadvantage: period of fertility cannot be 100% accurately predicted
• fertility drugs can be used to increase the chance of pregnancy
• the main hormones used when treating infertility are LH and FSH given to a woman in a 'fertility drug'. This stimulates the maturation and release of eggs, and she may then become pregnant in the normal way
• IVF:

  • the mother is given FSH and LH to stimulate the maturation of several eggs
  • the eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
  • the fertilised eggs develop into embryos.
  • at the stage when they are tiny balls of cells, one or two embryos are inserted into the mother’s uterus (womb) with the hop that at least one embryo will survive
• although fertility treatments give women a chance to have a baby:

  • it is very physically and emotionally stressful
  • success rates are not very high, and drastically decrease with age
  • fertility treatments are very expensive
  • it can lead to multiple pregnancies and births which are a risk to the babies and the mother