IVF Babble

Researchers uncover ‘golden window’ for IVF success

A new study has identified a slippery substance that may be stopping embryos from implanting during the final stages of an IVF cycle

Researchers at RMIT University believe they may have found a way of pinpointing when the Teflon-like molecule that makes the surface of the womb slippery and decreases.

The team discovered that the levels of this molecule on the womb’s surface decrease at a certain point in the menstrual cycle, allowing the womb to become stickier, opening the ‘golden window’ for pregnancy success.

Previously, scientists believed implantation hinged on molecules that actively promoted the adhesion of an embryo to the wall of the uterus.

Lead researcher Professor Guiying Nie said the team’s discovery changed long-held scientific thinking about embryo implantation.

She said: “We’ve been looking for something that helps embryos stick when the vital part of the puzzle turned out to be a slippery molecule that has the opposite effect – it prevents them from sticking.”

The research found a significant difference in IVF success rates when embryos were transferred while this molecule was present or absent on the surface of the uterus

“Every embryo is precious for families struggling with infertility, so getting the timing right is critical,” said Nie, who leads the Implantation and Pregnancy Research Laboratory in the School of Health and Biomedical Sciences at RMIT.

“We hope with further development our discovery could help clinicians identify precisely when each patient has the greatest chance of achieving pregnancy, delivering fully personalised IVF treatment.”

The findings, published in the journals Fertility and Sterility and Human Reproduction, could have significant implications for IVF treatment and success rates

The retrospective clinical study, co-designed by Professor Nie and Professor Luk Rombauts from Monash IVF, examined levels of the anti-implantation molecule, known as podocalyxin (PCX), in the endometrium of 81 women undergoing IVF treatment.

A biopsy of the uterus was taken at the mid-luteal phase (about seven days after ovulation) of the women’s menstrual cycle, one full cycle before a frozen embryo was transferred.

While the women with low levels of PCX had a 53 percent pregnancy success rate, those women where the molecule had not been reduced had a success rate of just 18 percent.

Professor Rombauts said measuring levels of PCX at the mid-luteal phase can be used as a screening test, but it could also indicate a reason for infertility, making the molecule a potential target for treatment.

Researchers have said the team has already began to work to better understand the role of PCX and how it is regulated in the body, with the hope of developing infertility treatments.

Further research will be needed to develop a non-invasive way of measuring PCX on the day of embryo transfer.

Professor Nie said: “Our hope is to deliver a simple test that can help patients and boost the precision and personalisation of IVF treatment.”

The work began at the Hudson Institute of Medical Research, before Nie’s team moved to RMIT in 2020.

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



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