Delays in the final stages of fertilization are strongly associated with trichotomous cytokinesis and cleavage arrest.

Purpose: Recent evidence showed that the phase between pronuclear fading and the first cleavage is a perilous bridge connecting the zygote and the embryo. Indeed, delay in the short interval between pronuclear breakdown (PNBD) and the first cytokinesis may result in chromosome segregation errors. We tested the hypothesis that delays in this final phase of fertilization are associated with a detrimental impact on embryo development.

Trophectoderm, Inner Cell Mass, and Expansion Status for Live Birth Prediction After Frozen Blastocyst Transfer: The Winner Is Trophectoderm.

Despite advancements in technologies such as time-lapse microscopy and artificial intelligence, the gold standard for embryo selection still relies on standard morphological assessment. Several studies have investigated the correlation between blastocyst characteristics (expansion status, inner cell mass, and trophectoderm) and clinical outcomes, reaching contradictory results. In consideration of these ambiguities in the literature, we performed a retrospective study of 1546 untested first-vitrified-warmed single day 5/6 blastocyst transfers.

The new ice age: the promise and challenges of rapid oocyte warming protocols.

Oocyte cryopreservation has transformed assisted reproductive technology, providing enhanced flexibility and efficacy in assisted reproductive technology treatments. The shift from traditional slow freezing to vitrification has markedly improved survival rates by preventing ice crystal formation, which can damage cellular structures. Despite these advances, rapid warming of vitrified oocytes remains a challenge due to the unique sensitivity of oocytes to thermal and osmotic stress, which can compromise spindle integrity and developmental competence.

Time will tell: time-lapse technology and artificial intelligence to set time cut-offs indicating embryo incompetence.

Study Question: Can more reliable time cut-offs of embryo developmental incompetence be generated by combining time-lapse technology (TLT), artificial intelligence, and preimplantation genetics screening for aneuploidy (PGT-A)?

Summary Answer: Embryo developmental incompetence can be better predicted by time cut-offs at multiple developmental stages and for different ranges of maternal age.

What Is Known Already: TLT is instrumental for the continual and undisturbed observation of embryo development. It has produced morphokinetic algorithms aimed at selecting embryos able to generate a viable pregnancy, however, such efforts have had limited success.

To Assess or Not to Assess: Reconsidering Day 3 Embryo Quality in Planned Freeze-All Blastocyst Cycles.

Day 3 embryo quality is a predictor of in vitro fertilization (IVF) success rates in cleavage-stage embryo transfer. However, the association between day 3 embryo quality and clinical outcomes in blastocyst transfer policy is largely unknown. This retrospective study included 1074 frozen-thawed single day 5/6 blastocyst transfers between January 2019 and December 2022.

Too many embryos: a critical perspective on a global challenge.

Over the past decade, significant endeavors have been directed toward establishing an optimal oocyte number to maximize the chances for successful in vitro fertilization outcomes. The effectiveness of assisted reproductive technologies has greatly improved, and more good-quality embryos are being created in each cycle. However, many of these embryos remain unused.

The Task Matters: A Comprehensive Review and Proposed Literature Score of the Effects of Chemical and Physical Parameters on Embryo Developmental Competence.

To explore the effects of chemical and physical parameters on embryo developmental competence, we conducted a systematic search on PubMed for peer-reviewed original papers using specific keywords and medical subject heading terms. Studies of interest were selected from an initial cohort of 4141 potentially relevant records retrieved. The most relevant publications were critically evaluated to identify the effect of these parameters on embryo development.

Endometriosis affects the number of retrieved oocytes but not early embryonic development and live birth: a retrospective analysis of 716 IVF cycles.

To investigate the potential effect of endometriosis on embryo development and clinical outcomes, a retrospective analysis of 716 women undergoing their first standard in vitro fertilization (sIVF) cycles (205 endometriosis and 511 with tubal factor infertility) was performed. The endometriosis group included women with an ultrasonographic or surgical diagnosis. Control subjects were women diagnosed with tubal factor infertility by laparoscopy or hysterosalpingogram.

Does morphological assessment predict oocyte developmental competence? A systematic review and proposed score.

Purpose: Does existing scientific literature suggest an impact of oocyte dysmorphisms on biological or clinical outcomes of assisted reproduction treatments?

Methods: Studies of interest were selected from an initial cohort of 6651 potentially relevant records retrieved. PubMed was systematically searched for peer-reviewed original papers and reviews identified by keywords and medical subject heading (MeSH) terms. The most relevant publications were critically evaluated to identify criteria for oocyte morphological evaluation and IVF outcomes.

Early embryo morphokinetics is a better predictor of post-ICSI live birth than embryo morphology: speed is more important than beauty at the cleavage stage.

Given the importance of embryo developmental competence assessment in reproductive medicine and biology, the aim of this study was to compare the performance of fertilization and cleavage morphokinetics with embryo morphology to predict post-ICSI live birth. Data from embryos cultured in a time-lapse microscopy (TLM) incubator and with known live birth outcomes (LB: embryos achieving live birth, n = 168; NLB: embryos not achieving live birth, n = 1633) were used to generate receiver operating characteristic (ROC) curves based on morphokinetic or morphological scores, and the respective areas under the curve (AUC) were compared. The association between live birth and 12 combinations of four morphokinetic quality degrees (A-D) with three morphological quality degrees (A-C) was assessed using multivariate analysis.

Faster fertilization and cleavage kinetics reflect competence to achieve a live birth after intracytoplasmic sperm injection, but this association fades with maternal age.

Objective: To assess the relationship of early developmental kinetics with competence to provide a live birth and the impact of maternal age in this context.

Design: Retrospective cohort study including 4,915 embryos, of which 1,390 were transferred and provided a clinical outcome paired with morphokinetic data; 168 of them resulted in a live birth (LB), and 1,222 did not (NLB). Early morphokinetic parameters were compared between LB and NLB embryos from patients stratified into two age groups (<37 and ≥37 years), and between embryos at the same competence group from patients aged <37 and ≥37 years.

The first report of pregnancies following blastocyst automated vitrification in Europe.

Embryo cryopreservation is a valuable technique in assisted reproductive technology (ART) that increases cumulative pregnancy rates and allows postponement of embryo transfer in patients with undesirable uterine or clinical conditions. Although vitrification has been considered the most efficient method to freeze oocytes and embryos, it is time-consuming and highly operator-dependent. Gavi® is the first semi-automated machine for vitrification capable of controlling crucial variables such as temperature, volume, concentration and exposure time during the vitrification process.

Maternal body mass index affects embryo morphokinetics: a time-lapse study.

Purpose: To assess the effect of body mass index (BMI) on morphokinetic parameters of human embryos evaluated with time-lapse technology during in vitro culture.

Methods: A retrospective analysis of ART cycles utilizing time-lapse technology was undertaken to assess the potential impact of maternal BMI on morphokinetic and static morphological parameters of embryo development. The cohort of patients was divided into four groups: 593 embryos from 128 underweight women in group A; 5248 embryos from 1107 normal weight women in group B; 1053 embryos from 226 overweight women in group C; and 286 embryos from 67 obese women in group D.

Seminal plasma of men with severe asthenozoospermia contain exosomes that affect spermatozoa motility and capacitation.

Objective: To characterize in depth and investigate the role of exosomes present in seminal plasma in affecting parameters underlying sperm activity.

Design: In vitro experimental study.

Setting: Research hospital.

Abnormal sperm concentration and motility as well as advanced paternal age compromise early embryonic development but not pregnancy outcomes: a retrospective study of 1266 ICSI cycles.

Purpose: To investigate the effect of sperm concentration, motility and advanced paternal age on reproductive outcomes.

Methods: A retrospective analysis of 1266 intracytoplasmic sperm injection (ICSI) cycles between 2013 and 2017. The cohort was divided into four groups according to semen concentration based on the WHO criteria (2010): group A (conc.