The use of hormones to treat infertility (HT only): In Vitro Fertilisation (IVF) treatment.

The idea

In Vitro Fertilisation (IVF) is a Higher Tier-only topic detailing how hormones treat infertility. The process begins by administering FSH and LH to the mother to stimulate the maturation of several eggs. These eggs are collected and fertilised by sperm from the father in a laboratory. The fertilised eggs develop into embryos. Once they form tiny balls of cells, one or two embryos are inserted into the mother's uterus to develop. While IVF helps overcome infertility (e.g., blocked oviducts), it has drawbacks: it is emotionally and physically stressful, success rates are not high, and it can lead to multiple births, which pose risks to both babies and the mother.

What earns the marks

• FSH and LH are given to the mother to stimulate the maturation of several eggs.
• Eggs are collected from the mother and fertilised by sperm from the father in the laboratory.
• The fertilised eggs develop into embryos, which are tiny balls of cells.
• One or two embryos are inserted into the mother's uterus (womb) to establish a pregnancy.
• IVF treatments can result in multiple births, which increases the risk to both the mother and the babies.
• IVF is physically and emotionally stressful and has a relatively low success rate.

Common mistakes and how to put them right

• Stating that fertilisation occurs inside the uterus during IVF.

  Put it right: Fertilisation happens outside the body in a laboratory; only the developing embryo is inserted into the uterus.

• Confusing the roles of FSH and LH in IVF.

  Put it right: Both FSH and LH are given to stimulate the maturation of several eggs, not just one, to increase the chances of successful collection.

• Assuming IVF is always successful and risk-free.

  Put it right: IVF has relatively low success rates, is physically and emotionally stressful, and carries the risk of multiple births.

Exam tips

• This specific topic (the use of hormones to treat infertility, including IVF) is assessed at Higher Tier only.
• When evaluating IVF, provide a balanced argument: mention the benefit of having a child, but contrast this with drawbacks like physical stress or multiple birth risks.