Pregnancy ‘entrance exam’

Warwick Medical School researchers, Professor Jan Brosens and Professor Siobhan Quenby, have discovered an “entrance exam” of the womb which is essential to a successful pregnancy.

This “entrance exam” determines the success of an embryo implanting to the lining of the womb.

Understanding this process could help improve success rates with IVF which most often fails due to implant failure.
The research shows that high quality human embryos secrete a chemical, trypsin, which renders the lining of the womb supportive of implantation.

In low quality embryos this chemical signal is deregulated and causes an alarm response in the womb, leading to either rescue or elimination of the embryo.

The study began in 2012 in collaboration with University Hospitals Coventry and Warwickshire NHS Trust and was supported by researchers at the Universities of Southampton and Utrecht.

Approximately 15 percent of pregnancies end in miscarriage. Recurrent miscarriage – losing three or more pregnancies in a row – affects one in 100 in the UK.

Professor Brosens explained: “If the lining of the womb is not well prepared for pregnancy you may find that abnormal embryos will implant or high quality embryos will not be supported.

“Both scenarios can lead to pregnancy loss or even late pregnancy complications.”

“Speaking in terms of an entrance exam; a poorly prepared womb will either make the test too rigorous or too lax – decreasing the chances of a successful pregnancy.”

Professor Quenby said: “This work adds to a growing body of evidence that assessment and optimisation of the lining of the womb may be the only effective way in preventing infertility and pregnancy complications.”

Professor Brosens added: “What we’re looking at now is how to alter the lining of the womb so it can set this entrance exam at the right level and prevent miscarriages.”