Here you’ll find a brief summary of new IVF studies for January 2024* that I think are helpful for patients. I’ll be updating this post each week of January 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.
🔗 Original studies are referenced in this post or within the linked Remembryo posts.
💡 Reminder: Terms underlined with a dotted black line are linked to glossary entries. Clicking these does not count toward your paywall limit.
Table of Contents
Week 1 (Jan 2 – Jan 8)
Multiple embryo manipulations in PGT-A cycles may result in inferior clinical outcomes. In a small study, embryos that were biopsied twice had an increased miscarriage rate. There were no differences in euploidy rates or live birth rates (after statistical adjustment). You can check out another recent study that was much larger on rebiopsied embryos here.
Clinical outcomes of preimplantation genetic testing for aneuploidy in high-risk patients: a retrospective cohort study. Patients with advanced maternal age, recurrent implantation failure, recurrent pregnancy loss and severe male factor all had PGT-A. Patients all had better ongoing pregnancy/live birth rates with PGT-A, and had lower chances of pregnancy loss.
IVF versus IUI with ovarian stimulation for unexplained infertility: a collaborative individual participant data meta-analysis. A meta-analysis combined the results of 6 randomized controlled trials (RCTs) that compared unexplained infertility patients doing IVF or an IUI. There was no difference in cumulative live birth rates between IUI and IVF, and no difference in multiple pregnancy rates.
Vertical transmission of maternal DNA through extracellular vesicles associates with altered embryo bioenergetics during the periconception period. This study outlines the discovery of extracellular vesicles secreted naturally by the endometrium that are taken up by the embryo that could assist in implantation. These vesicles are tiny structures that can carry different messages from the endometrium to the embryo.
Week 2 (Jan 9 – Jan 15)
An immune window of opportunity to prevent spontaneous abortion: prepregnancy peripheral leukocytes and subsets were associated with a decreased risk of spontaneous abortion. Over 1 million women preparing for pregnancy had a blood test and their peripheral white blood (immune) cells measured to identify any links to pregnancy loss. Over 35,000 losses occurred, and women with a pregnancy loss were more likely to have low levels of white blood cells, with increases in some cell types (ie. eosinophils and lymphocytes like NK cells) and decreases in others (ie. neutrophils, monocytes). For more information on how immunotherapies affect IVF outcomes, check here.
Individualised gonadotropin dose selection using markers of ovarian reserve for women undergoing in vitro fertilisation plus intracytoplasmic sperm injection (IVF/ICSI). A new Cochrane meta-analysis combined the results of 26 studies to see how individualized FSH dosing, based on different ovarian reserve tests, improves IVF outcomes. Overall, there is no “clear justification for adjusting the dose of 150 IU in poor or normal responders.”
Single-cell DNA sequencing reveals a high incidence of chromosomal abnormalities in human blastocysts. In conventional PGT-A, a biopsy of 5-10 cells is usually used to determine if an embryo is euploid, aneuploid or mosaic. In this study, researchers tested individual cell of 55 embryos, finding that about 82% were mosaic. Most of the mosaics had <20% abnormal cells — which would have tested as euploid by conventional PGT-A.
Effects of Physical Activity on Fertility Parameters: A Meta-Analysis of Randomized Controlled Trials. A meta-analysis combined the results of 47 randomized controlled trials (RCTs) investigating the effect of physical activity on semen parameters and male fertility. With increased physical activity, this study found improvements in sperm concentration, motility, normal morphology, pregnancy rate and live birth rate.
Week 3 (Jan 16 – Jan 22)
Adding L-carnitine to antagonist ovarian stimulation doesn’t improve the outcomes of IVF/ ICSI cycle in patients with polycystic ovarian syndrome: a double-blind randomized clinical trial. In this randomized controlled trial (RCT), PCOS patients received the supplement L-carnitine before IVF. There was no difference in IVF outcomes, like egg maturity, fertilization and clinical pregnancy rates. However, there was improved weight loss and serum blood sugar levels. If you want to read more about egg quality supplements, check this post.
Outcomes comparison of testicular versus ejaculated sperm for intracytoplasmic sperm injection in infertile men with high DNA fragmentation: updated systematic review and meta-analysis. A meta-analysis combined the results of 11 studies that compared ejaculated vs testicular sperm in men with high sperm DNA fragmentation (SDF). They found that SDF rates were lower in testicular sperm and that testicular sperm had better outcomes, including improved pregnancy, live birth and miscarriage rates.
Challenges experienced by genetic counselors while they provided counseling about mosaic embryos. Genetic counsellors were surveyed on mosaic embryo transfer challenges and practices. This study surveys genetic counsellors on challenges and common guidance for mosaic embryo transfers. Some challenges included the uncertainty of outcomes in offspring, limited guidelines and ranking mosaics for transfer. Most genetic counsellors recommended amniocentesis after mosaic transfers. You can read more about mosaic embryos here.
Immunological Aspects of Infertility—The Role of KIR Receptors and HLA-C Antigen. This review discusses natural killer (NK) cells, their KIR receptors and the impact of NK cell/embryo interactions on embryo implantation. If you want to check out a recent meta-analysis on the use of immunotherapies for IVF, check here.
Week 4 (Jan 23 – Jan 29)
Effect of Stress on Each of the Stages of the IVF Procedure: A Systematic Review. This review included 36 studies that examined stress and outcomes for different stages of IVF. They found that the egg retrieval was affected by chronic and acute stress, the transfer stage was only affected by chronic stress and that the pregnancy stage was weakly affected by stress. Cortisol levels and surveys were used to establish stress levels.
Do IVF culture conditions have an impact on neonatal outcomes? A systematic review and meta-analysis. A total of 28 studies were combined that examined embryo culture conditions and obstetric/neonatal complications. They found no difference for embryo culture oxygen concentrations or for different culture medias used.
Advanced Paternal Age: A New Indicator for the Use of Microfluidic Devices for Sperm DNA Fragmentation Selection. This study used donor eggs and Zymot to select sperm. They found that live birth rates increased with Zymot, particularly in men 45 or older. They didn’t measure sperm DNA fragmentation levels.
Endometriosis diagnosed by ultrasound is associated with lower live birth rates in women undergoing their first IVF/ICSI treatment. Women with deep infiltrating endometriosis or endometriomas (diagnosed using transvaginal ultrasound) had lower cumulative live birth rates than women without the condition.
If you want to get even more of the latest research each week, you can sign up for a paid subscription to Remembryo to get an upgraded weekly newsletter. Plus, you’ll be supporting me in my efforts to share the latest IVF research!
