A new discovery indicates the "golden window" for the success of IVF

Key points

• Teflon-like molecules make the uterus smooth and prevent embryo implantation

• Studies have found that when slip molecules are reduced, in vitro fertilization is more likely to be successful

• This discovery helps to improve the accuracy and personalization of IVF treatment

It has long been known that the correct timing of embryo transfer is critical to the chance of pregnancy

However, it is still a challenge to accurately determine the right moment of a woman's menstrual cycle, which has led to a very low success rate of IVF, which is still less than 50% on average

But now researchers at RMIT University may have found a way forward.

The research team found that the level of this molecule on the surface of the uterus drops at a certain point in the menstrual cycle

This makes the uterus more viscous, opening the "golden window" for a successful pregnancy

Previously, scientists believed that implantation depends on molecules that actively promote the adhesion of the embryo to the uterine wall

Lead researcher Professor Nie Guiying said that the team's discovery changed the scientific thinking about embryo implantation for a long time

She said: "We have been looking for substances that can help embryos to adhere, and it turns out that the key part of this puzzle is a smooth molecule that has the opposite effect-preventing embryos from adhering

Studies have found that there is a significant difference in the success rate of IVF when the embryo is present or absent on the surface of the uterus

"For infertile families, every embryo is precious, so choosing the right time is very important," said Nie, head of the Implantation and Pregnancy Research Laboratory, School of Health and Biomedicine, RMIT University

"We hope that through further research, our findings can help clinicians accurately determine when each patient is most likely to become pregnant, and provide a completely personalized IVF treatment

The results of this study, published in the journal Fertility and Infertility and Human Reproduction, may have a significant impact on IVF treatments and success rates

Pregnancy success rate

This retrospective clinical study was jointly designed by Nie and Professor Luk Rombauts of Monash IVF.

Uterine biopsy is performed in the middle of the luteal phase of the female menstrual cycle (about 7 days after ovulation), a complete cycle before the transfer of frozen embryos
.

The pregnancy success rate of women with low PCX levels is 53%, while the pregnancy success rate of women with no reduction in PCX molecules is only 18%
.

Rombauts said that measuring the level of PCX in the mid-luteal phase can be used as a screening test, but it may also indicate the cause of infertility, making this molecule a potential therapeutic target
.

He said: "These findings provide us with a promising path, which can both improve the success rate of in vitro fertilization and potentially treat the underlying causes of infertility
.
"

The research team has begun to better understand the role of PCX and how it is regulated in the body, with the goal of developing treatments for infertility
.

Nie said that this molecular analysis can be performed in a standard pathology laboratory, which makes future screening tests relatively cost-effective
.

"The only way we currently detect PCX is through tissue biopsy, which cannot be performed during embryo transfer," she said
.

"We need further research to develop a non-invasive real-time method for measuring PCX on the day of embryo transfer
.

"We hope to provide a simple test that can help patients and improve the accuracy and personalization of IVF treatment
.
"

This technology has been patented, and Monash IVF collaborators are further evaluating its potential clinical applications
.

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This work started at the Hudson Institute of Medical Research, after which Nie's team moved to RMIT in 2020
.

This research was supported by the European Society of Human Reproduction and Embryology, Monash IVF, and the National Health and Medical Research Council (NHMRC) of Australia
.
Research on human embryos in Brussels was supported by Wetenschappelijk Fonds Willy Gepts
.

Collaborators from the Free University of Brussels, University of Adelaide and Monash University published in "Fertility and Infertility" (DOI:10.
1016/j.
fertnstert.
2021.
06.
028)
.

The podocalyxin discovered by the team in human uterus and embryo implantation was originally published in Human Reproduction (DOI: 10.
1093/humrep/deab032)
.

Magazine

Fertility and infertility

DOI

10.
1016/j.
fertnstert.
2021.
06.
028

Methodological research

Experimental Study

Subject of research

people