Monthly IVF research brief for April 2024

Here you’ll find a brief summary of new IVF studies for April* that I think are helpful for patients. I’ll be updating this post each week of April 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 (April 2 – 8)

EFFECT OF POST-THAW CHANGE IN EMBRYO SCORE ON SINGLE EUPLOID EMBRYO TRANSFER SUCCESS RATES. Occasionally, an embryo’s grade changes after thawing. In this study, researchers compared outcomes for thawed euploids that had no change in grade, improved grades, worsened grades or didn’t re-expand. Embryos that were downgraded or didn’t re-expand had a lower chance of live birth.

Testicular sperm retrieval for intracytoplasmic sperm injection: when to consider it after unsuccessful intracytoplasmic sperm injection with ejaculated sperm? Patients with oligozoospermia (low sperm count) had unsuccessful ejaculate-ICSI cycles before moving on to testicular-ICSI. Testicular-ICSI patients had improved total motile sperm counts and lower DNA fragmentation, which were found to be associated with live birth rates.

Abnormal cleavage up to Day 3 does not compromise live birth and neonatal outcomes of embryos that have achieved full blastulation: a retrospective cohort study. Abnormal cleavage, like direct cleavage or reverse cleavage, has been linked to worsened IVF outcomes. This study found that embryos with a history of abnormal cleavage have a reduced chance of becoming an expanded blastocyst, but once they become a blastocyst, there isn’t any reduction in live birth rates.

Adverse drug reactions on male fertility. This article reviews medications that are known to have a negative impact on male fertility.

Week 2 (April 9 – 15)

Excessive Exogenous Gonadotropins and Genetic and Pregnancy Outcomes After Euploidy Embryo Transfer: A Secondary Analysis of a Randomized Clinical Trial. This study compared total gonadotropin dose and duration and the chance of getting a mosaic embryo, as well as pregnancy outcomes after transferring a euploid from the same IVF cycle. They found that women with a higher total gonadotropin dose were more likely to produce mosaic embryos, and had a lower cumulative chance of live birth.

The impact of (very) young donor age on euploid rates: An analysis of 1831 trophectoderm biopsies evaluated with 24-chromosome NGS screening in oocyte donation cycles. This study compared aneuploidy rates in egg donors based on their age, from 18 to 35. Aneuploidy levels increased with the age of the egg donor, with embryos derived from egg donors <22 years old having the lowest chance of aneuploidy.

Adverse Pregnancy Outcomes and Long-Term Mortality in Women. This study found that women with a history of any of the 5 major adverse pregnancy outcomes (preterm delivery, small for gestational age, preeclampsia, other hypertensive disorders, gestational diabetes) had an increased risk of premature mortality more than 40 years later.

Impact of thyroid autoimmunity on the cumulative live birth rates after IVF/ICSI treatment cycles. This study found no difference in cumulative live birth rates and thyroid autoimmunity, even in a subgroup with different types and titres of thyroid antibodies.

Week 3 (April 16 – 22)

Modified natural cycle allows a window of 7 days for frozen embryo transfer planning. Medicated frozen embryo transfers are preferred by physicians because of their flexibility in scheduling, but involve more drugs and are associated with a higher rate of complications compared to modified natural cycle FETs (mNC FETs). mNC FETs have stricter scheduling and are often triggered around a follicle size of 17 mm, but this study found equivalent pregnancy outcomes with follicles triggered between 13-22 mm, providing physicians with a more flexible window of 7 days in performing mNC FETs.

Effect of time post warming to embryo transfer on human blastocyst metabolism and pregnancy outcome. After an embryo is thawed, it’s normally put into culture to re-expand for a few hours before transfer, but this timing can vary. This study found no difference in pregnancy outcomes for embryos thawed and kept in culture for up to 8 hours before transfer.

The utility of human two plus one small pronucleated zygotes (2.1PN) based on clinical outcomes and the focused ploidy analysis. During normal fertilization 2 pronuclei (PN) appear, but abnormally fertilized zygotes could show smaller pronuclei, called a 2.1 PN. This study found that 2.1 PN embryos are less likely to form blastocysts, but can result in healthy babies.

Effectiveness of recombinant human FSH: recombinant human LH combination treatment versus recombinant human FSH alone for assisted reproductive technology in women aged 35-40 years. During ovarian stimulation, either FSH alone or a combination of FSH and LH can be used. This study found no difference in clinical pregnancies or live births for patients who used FSH or FSH/LH, except in a post-hoc analysis of patients with 5-14 eggs retrieved aged 35-40.

Week 4 (April 23 – 29)

Total duration of spontaneous blastocyst collapse during the expansion stage is an independent predictor of euploidy and live birth rates. Blastocysts contain a cavity called a blastocoel that’s filled with water, and as the blastocyst grows the blastocoel will occasionally collapse or shrink. This study found that blastocysts that collapse more often are more likely to be aneuploid and lower quality.

Multivariate analyses on male factors and construction of a nomogram for predicting low in vitro fertilization rate. This study built a type of calculator called a nomogram to help predict male factors for low/no fertilization. After statistical analysis, sperm progressive motility, sperm acrosin activity and sperm concentration were found to be risk factors.

Rescue intrauterine insemination in women failing to retrieve oocytes at ovum pick-up: report of a case series. This study examined the use of “rescue IUI,” where a patient with 3 or less follicles received IUI after an unsuccessful egg retrieval. The live birth rate using this method was 6.2%.

Effect of Day 3 cell number on the live birth rate of vitrified-warmed Day 5 single blastocyst transfer in young women. This study transferred single blastocysts, while noting their day 3 cell number. Blastocysts that had a higher number of cells on day 3 (>9) had a higher chance of live birth, but there were no differences in miscarriage rate.

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