New Research Uncovers a "Golden Window" for IVF Success
By Nikki Novick
Researchers discover a way to better pinpoint the 'golden window' when a womb is ready for pregnancy, in a discovery that could help amplify IVF success rates.
IVF stands for in vitro fertilization which is one of the most effective types of assisted reproductive technology (ART). In vitro fertilization (IVF) is a series of procedures used to help with fertility or prevent genetic problems and assist with the conception of a baby.
IVF helps with fertilization, as well as embryo development and implantation, so you can get pregnant. IVF works by using a combination of medications and surgical procedures to help sperm fertilize an egg, and help the fertilized egg implant in your uterus.
During IVF, mature eggs are retrieved from the ovaries and fertilized by sperm in a lab. The fertilized eggs (embryos) are then transferred to the uterus. Pregnancy happens if any of the embryos implant in the lining of the uterus.
It is known that correctly timing an embryo transfer is crucial for achieving pregnancy through the use of IVF. Correctly identifying the right moment in a woman’s cycle remains one of the biggest challenges of IVF, contributing to low IVF success rates. According to a report from 2018, only about 50 percent of IVF procedures resulted in live birth, and for women ages 42 and older, the success rate was about 4 percent.
Changes in the laboratory have been transmitted to clinical care, showing dramatic improvements in health outcomes. IVF is the perfect example of translational research, with an increase in pregnancy rate from 5% to 50% since 1978 and the rate of multiple gestations in a dramatic decline secondary to the development of technology to assess embryos.
A lot has to do with negative outcomes that can have an impact on all pregnancies, such as chromosomal abnormalities in the embryo, uterine lining or placental issues or even fetal growth problems. Image courtesy of todaysparent.com.
Researchers at RMIT University identified a Teflon-like molecule that makes the surface of the womb slippery which prevents embryos from implanting. The study finds that IVF is more likely to succeed when this slippery molecule is reduced.
Recognizing when there are higher levels of this molecule in the uterus may make it easier to find the right time for implantation. The team discovered that the levels of this molecule on the womb's surface decrease at a certain point in the menstrual cycle which allows the womb to become stickier, opening the “golden window” for pregnancy success.
Scientists had previously believed that implantation hinged on molecules that actively promoted the adhesion of an embryo to the wall of the uterus.
The lead researcher, Professor Guiying Nie said that the team’s discovery changed long-held scientific thinking about embryo implantation. Embryo implantation is a process in which developing embryos, moving as a blastocyst through a uterus, makes contact with the uterine wall and remains attached to it until birth.
“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,” she said.
As successful implantation requires a competent blastocyst embryo interacting with a receptive endometrial (uterine) lining, the researchers found a significant difference in the 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.
The lack of fertility can have a number of causes, so the first step should be to visit with your OB-GYN to determine if there is a cause of your infertility. For most couples, there is only a 20-percent chance of pregnancy in any given month. Image courtesy of morelandobgyn.com.
The search for the perfect embryo, the one that can undergo single embryo transfer with genetic screening for success, is the Holy Grail of IVF.
Nie explained, “We hope with further development our discovery could help clinicians identify precisely when each patient has the greatest chance of achieving pregnancy, delivering fully personalized IVF treatment.”
The retrospective clinical study, co-designed by 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 (which is 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% pregnancy success rate, those women where the molecule had not been reduced had a success rate of just 18%.
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. “These findings offer a promising path for us to both improve IVF success rates and potentially treat an underlying cause of infertility,” he concluded.
The findings of this study may have significant implications for IVF treatment and success rates and even potentially help treat an underlying cause of infertility. The discovery of the Teflon-like molecule was a huge success as the study shows that this molecule makes the surface of the womb slippery, which prevents embryos from implanting. Not only did the study find that IVF is more likely to succeed when this slippery molecule is reduced, but it also provides a new underlying cause of infertility, in which the findings of this study could potentially help treat. Research continues to further improve the ability to maximize the outcomes of IVF procedures and provide optimal counseling for expectant outcomes to patients.