Researchers in a 2020 review performed a meta-analysis and combined the results of studies that looked at embryo glue and IVF outcomes, and found an improvement in live birth rates and other outcomes.
What is Embryo Glue?
First off – what is Embryo Glue anyway? It’s a product sold by VitroLife that contains a chemical called hyaluronic acid (aka hyaluronan). Hyaluronic acid is a long-chain carbohydrate polymer that is an important component in cartilage, muscular connective tissue, skin and skin repair. It is often sold as a skincare product to help hydrate the skin and make it look more “radiant and youthful”. When it combines with water, it forms a viscous, jelly-like consistency that acts like a lubricant and shock absorber.
It is also present in the female reproductive system, and its concentration peaks in the endometrium during certain parts of the menstrual cycle. It’s not clear if this is directly involved in promoting embryo implantation or not.
Besides forming a goo-like substance, hyaluronic acid is also present on the surface of certain cells. Embryos actually have receptors for hyaluronic acid, as well as certain cells of the endometrium. This might might help them bind to the endometrium.
🔗 Original studies are referenced in this post or within the linked Remembryo posts.
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How does Embryo Glue help implantation?
As mentioned, Embryo Glue (which contains hyaluronic acid) isn’t actually glue at all, but it forms a viscous solution that the embryo is suspended in. During transfer, it’s thought that this might prevent expulsion of the embryo from the uterine cavity. Another possibility is that this viscous solution more closely resembles the viscous solution of the intrauterine environment, so the embryo can “mix” in and become better integrated into the intrauterine environment.
Does Embryo Glue work?
So what kind of evidence is out there for hyaluronic acid improving implantation?
Let’s take a look at a recent 2020 Cochrane review that performed a meta-analysis on the available data. They looked at a ton of stuff! Note that they looked at studies that used either high levels of hyaluronic acid (HA) or low/no HA, so all the positive benefits you’re about to see are for the high levels of HA (which is what is contained in Embryo Glue).
Overall live birth rate. Improvement in live birth rate by 21% (risk ratio [95% CI]: 1.21 [1.11-1.31]) based on 10 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 33.3% – 39.3%.
Cleavage stage embryo transfers – the live birth rate increased 19% (risk ratio [95% CI]: 1.19 [1.05-1.35]) based on 6 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 31.5% – 40.5% using cleavage stage embryos.
Blastocyst stage embryo transfers – the live birth rate increased 22% (risk ratio [95% CI]: 1.22 [1.05-1.42]) based on 4 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 31.5% – 42.6% using blastocysts.
This is interesting because even embryos that are transferred at an earlier stage see the benefit. So whatever the mechanism is that’s causing HA to improve live birth rates is long-lasting (because Day 3 embryos need to develop a few days in the uterus before finally implanting).
Fresh embryo transfers – the live birth rate increased 28% (risk ratio [95% CI]: 1.28 [1.15-1.41]) based on 6 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 34.5% – 42.3% with a fresh embryo transfer.
Frozen embryo transfers – the live birth rate was not increased significantly (risk ratio [95% CI]: 0.99 [0.80-1.24]) based on 3 studies.
This is interesting that there’s an effect with fresh transfers, but not with frozen transfers. A recent RCT was published by Yung et al. 2021 that found no improvement in FET cycles with those who used embryo glue compared to those who did not (live birth rate was 25.5% vs 25.8%, relative risk [95% CI]: 0.99 [0.74-1.31]). It’s not clear why this is.
They also looked at exposure time. This is the amount of time the embryo spent in the HA-containing media before being transferred.
Exposure time 10 minutes – the live birth rate was not increased significantly (risk ratio [95% CI]: 1.14 [0.92-1.41]) based on 3 studies.
Exposure time >10 minutes – the live birth rate increased 20% (risk ratio [95% CI]: 1.20 [1.09-1.32]) based on 5 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 32.7% – 39.6% with a >10 minute exposure time to the HA-containing media.
Many studies only included good prognosis women in the study, so they combined these.
Good prognosis – the live birth rate increased 24% (risk ratio [95% CI]: 1.24 [1.09-1.40]) based on 6 studies. So if the base live birth rate is 30%, then high-HA containing media (like Embryo Glue) would increase this to 32.7% – 42.0% in good prognosis patients.
So Embryo Glue, or any media that contains HA, seems to work well (at least for fresh transfers). It’s also pretty affordable apparently, so it might be worth trying out!
Reference
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About Embryoman
Embryoman (Sean Lauber) is a former embryologist and the founder of Remembryo, an IVF research and fertility education website. After working in an IVF lab in the US, he returned to Canada and now focuses on making fertility research more accessible. He holds a Master’s in Immunology and launched Remembryo in 2018 to help patients and professionals make sense of IVF research. Sean shares weekly study updates on Facebook, Instagram, and Reddit regularly. He also answers questions on Reddit or in his private Facebook group.
Related posts:
Complete guide to embryo implantation and implantation failure
Meta-analysis shows benefit of embryo glue when using own eggs, not donor
Endometrial scratch doesn’t increase success rates in a large randomized trial
IVF pregnancy outcomes after intrauterine PRP: a 2022 clinical trial
Meta-analysis of commonly used IVF immunotherapies shows no benefit
Meta-analysis finds no difference in pregnancy outcomes when using the ERA
RCT finds no change in birth rates for standard or ERA-timed euploid transfer
Evidence-based recommendations from ESHRE for 27 IVF add-ons