University of York

Biochemistry of early human embryos (R0067)

Licence holder: Professor Henry Leese

Lay Summary:

Up to 1 in 6 couples find difficulty in conceiving. For many, one solution to their infertility is In Vitro Fertilisation and Embryo Transfer (IVF-ET) the so-called "test tube baby" treatment, which was pioneered in the UK in the late 1970s.

This treatment has helped many thousands of couples to have children, but success rates remain disappointingly low with a live birth rate per treatment cycle in the UK of only around 20%. Moreover, since 2, exceptionally 3 embryos may be transferred in any one treatment cycle, there is a risk of multiple births. While the birth of a baby is a cause for joy, multiple births can unfortunately bring problems; the babies are often underweight and peri-natal mortality is above average; the parents may also have problems in coping with the arrival of a large family.

There is now good agreement amongst doctors and embryologists that a solution to these problems would be to transfer single embryos with a high chance of forming a pregnancy. However, we know very little about how human embryos are formed and what makes some embryos more healthy than others.

The aim of our work is therefore to carry out a detailed examination of the development of the early human embryo. In this way we will learn how to improve culture conditions and devise diagnostic methods that allow the transfer of single, healthy embryos with a high chance of giving rise to a pregnancy and minimising the risk of multiple births. Eventually, this will help ensure the health of babies born following natural conception as well as IVF.