Monthly IVF research brief for August 2024

Here you’ll find a brief summary of new IVF studies for August* that I think are helpful for patients. I’ll be updating this post each week of August with new studies, before making a separate post for next month.

*Note that the publication dates of these studies might be outside of the indicated period, mostly because of how PubMed indexes the article.

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Week 1 (July 30 – Aug 5)

Comparisons of cumulative live birth rates after embryo transfers at day-2/3 versus day-5/6: a French national study. A study compared over 130,000 cycles to evaluate cleavage stage (day 2/3) and blastocyst stage (day 5/6) transfers. They found that cumulative live birth rates were higher for day 2/3 transfers per cycle, especially in cases where there were 3 or less day 2 embryos.

Assessing the developmental competence of oocytes matured following rescue in vitro maturation: a systematic review and meta-analysis. A meta-analysis combined the results of 24 studies that examined rescue in-vitro maturation (rescue IVM), a technique that aims to increase the number of mature eggs in a cycle by extending the culture of immature eggs. They found that rescue IVM eggs had reduced reduced fertilization, cleavage, blastulation, and clinical pregnancy rates compared to mature eggs, but could help poor responders get more eggs.

An expert opinion on rescuing atypically pronucleated human zygotes by molecular genetic fertilization checks in IVF. This review summarizes IVF outcome data from embryos that develop from abnormally fertilized eggs, like a 1PN or 3PN. Most labs discard these fertilized eggs, but research shows that over 50% are incorrectly classified, and PGT-A should be used to assist in classification.

Undisturbed culture: a clinical examination of this culture strategy on embryo in vitro development and clinical outcomes. This study compared outcomes for embryos that were cultured in a fully undisturbed system or one where the embryos were removed and assessed as normal. They found that undisturbed cultures resulted in embryos that had a higher first live birth rate in cycles with egg donors or with a patient’s own eggs.

Week 2 (Aug 6 – Aug 12)

Intravaginal probiotics before embryo transfer do not improve pregnancy rates in recurrent implantation failure cases: An RCT. A randomized controlled trial (high quality study) tested an intravaginal probiotic in patients with recurrent implantation failure, finding no statistical difference in clinical pregnancy rate.

Does it affect the live birth rates to have a maximum endometrial thickness of 7, 8, or 9 mm in in-vitro fertilization-embryo transfer cycles? This study found no difference in live birth rates for endometrial thicknesses 7.0 to 9.9 mm.

Endometriosis and risk of adverse pregnancy outcomes: a retrospective multicenter cohort study. This study found that women with endometriosis had higher risks of adverse pregnancy outcomes, including preterm birth, preeclampsia, placenta previa and other outcomes.

Extended versus conventional letrozole regimen in patients with polycystic ovary syndrome undergoing their first ovulation induction cycle: a prospective randomized controlled trial. A randomized controlled trial (high quality study) used an extended letrozole regimen on PCOS patients, and found no differences in ovulation rates compared to patients who used the conventional letrozole regimen.

Week 3 (Aug 13 – Aug 19)

Untangling the independent effect of endometriosis, adenomyosis, and ART-related factors on maternal, placental, fetal, and neonatal adverse outcomes: results from a systematic review and meta-analysis. This meta-analysis combined the results of multiple studies to investigate the effect of endometriosis and adenomyosis on adverse pregnancy outcomes. They found these conditions were linked to preterm birth, cesarean section, miscarriage, pre-eclampsia and other outcomes.

The effectiveness of prolonged downregulation with gonadotrophin-releasing hormone analogue (GnRHa) treatment in women with adenomyosis undergoing IVF/ICSI: A systematic review and meta-analysis. This meta-analysis combined the results of multiple studies to investigate the effect of prolonged GnRHa pre-treatment in patients with adenomyosis. GnRHa pre-treatment resulted in improved implantation and pregnancy rates, with no differences in live birth or miscarriage rates.

Embryonic aneuploidy – the true “last barrier in assisted reproductive technology”? This review summarizes how aneuploidy occurs in the egg, including meiotic segregation errors that can be promoted by factors such as cohesin complex deterioration and spindle assembly instability.

PGT-A is Associated with Reduced Live Birth Rates in Fresh but not Frozen Donor Oocyte IVF cycles: An Analysis of 18,562 Donor Cycles Reported to SART CORS. This study found reduced live birth rates for first transfer PGT-A cycles using fresh, but not frozen, donor eggs. Importantly, the study couldn’t control for age of the donor, which may have influenced the results.

IVF and obstetric outcomes among women of advanced maternal age (≥45 years) using donor eggs. This study found no differences in cumulative live birth rates in women 45 years or older who used donor eggs.

Week 4 (Aug 20 – Aug 26)

Preimplantation genetic testing for aneuploidy in unexplained recurrent pregnancy loss: A systematic review and meta-analysis. A meta-analysis combined the results of 18 studies that evaluated the use of PGT-A in patients with recurrent pregnancy loss. They found that embryos from RPL patients were more likely to be aneuploid, but once a euploid was transferred, RPL and non-RPL patients had a similar chance of pregnancy.

The association between female age and pregnancy outcomes in patients receiving first elective single embryo transfer cycle: a retrospective cohort study. This study evaluated outcomes for patients doing their first IVF cycle based on their age, finding that the number of eggs retrieved, number of embryos frozen, % of good quality embryos, and pregnancy rates all decreased with increasing age.

Derivative and non-derivative aneuploidy rates in PGT tested blastocysts from carriers of structural rearrangements. This study evaluated the chance of getting a euploid in patients that had a reciprocal translocation, Robertsonian translocation or inversion. Patients with inversions had the higher euploid rates.

Relationships between couple collaboration, well-being, and psychological health of infertile couples undergoing assisted reproductive treatment. This study found that while couple collaboration directly reduces depression in infertile couples undergoing ART, its effects on anxiety and stress are mediated by well-being during infertility. These findings suggest that mental health programs for infertile couples should focus on enhancing well-being through couple collaboration.

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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.

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