Recently, the World Health Organization recommendation for abstinence time for semen analysis has been challenged in some studies and many of them have supported the advantages of a second short abstinence ejaculation. More evidence is needed to approve this for clinical use. This study aimed to compare the average routine abstinence time (2–7 days) with the short time (1–2 h) on sperm quality based on functional parameters in a population of oligo-astheno-teratozoospermia (OAT) men. The semen samples were retrieved from 50 men with OAT two times: one standard 2–7 days (long ejaculation) and short duration trimming (1–2 hours later the first ejaculation). All semen parameters as well as sperm DNA integrity were compared between groups. Results showed that mean sperm concentration (10.40 vs. 8.76), total sperm count (28.53 vs. 12.24) and mean semen volume (2.69 vs. 1.40) were higher in the first ejaculation (2–7 days of abstinence), while progressive motility (20.52 vs. 13.32), non-progressive motility (53.46 vs. 48.86), morphology (2.46 vs. 1.46) and viability (83.90 vs. 77.96) were significantly higher in the second ejaculation (P < 0.05). The second sample also showed lower immotile (26.82 vs. 38.02) and DNA fragmentation (19.5 vs. 26.96) (P < 0.05). Taking all data into account, an additional short abstinence period (AP) may be a simple and helpful strategy to obtain better sperm quality in couples with male infertility causes, especially in OAT patients. The recommended current guidelines regarding the AP may need to be revisited in severe male factors.

A blastomere containing more than one nucleus is defined as a multinucleated blastomere. In our study, we aimed to investigate the relationship between serum anti-Mullerian hormone (AMH) levels and multinucleated (MLN) embryos, one of the parameters indicating embryo quality, in intracytoplasmic sperm injection (ICSI) cycles. The results of 888 ICSI cycles of patients aged 19–45 years attending an ART (assisted reproductive technology) clinic were retrospectively analysed. Cycles with at least one MLN embryo were defined as the study group (n = 237) and cycles without MLN embryos as the control group (n = 651). Univariate and multivariate logistic regression analyses were used to determine the risk factors affecting the dependent qualitative variables. The effect of AMH levels on multinucleation was found to be a significant risk factor (p < 0.001). One unit increase in AMH levels increases the risk of the presence of MLN embryos by 1.12 times. The mean MLN embryos/total embryo ratio in the group with clinical pregnancy was 0.34 ± 0.18, while the mean MLN embryos/total embryo ratio in the group that did not achieve clinical pregnancy was 0.47 ± 0.3 (p = 0.010). The presence of an MLN embryo has been associated with poor embryo development and ART outcomes. Parameters that can predict the formation of MLN embryos before treatment are crucial for the determination of the pregnancy rate. According to our results, serum AMH levels can be used as a predictive marker for the formation of MLN embryos.

Dry incubators prevent bacterial growth and allow time-lapse imaging. However, they cause more significant osmotic pressure changes in the culture medium than in humidified incubators. Few reports have explored the effect of osmotic pressure on human embryos cultured under different conditions. This study examined how changes in osmotic pressure affect human embryos in a dry incubator. The study incubated embryos in culture mediums covered with mineral oil of varying viscosities and quantities. The osmotic pressure of the culture medium was measured daily for six-day period (Day 0–6) in four experimental groups established by varying the viscosity and volume of mineral oil: low viscosity (Light), 3.0 ml or 4.5 ml, and high viscosity (Heavy), 3.0 ml or 4.5 ml of mineral oil. The Light 3.0 ml and Heavy 4.5 ml groups, showing the greatest difference in the osmotic pressure, were used to culture of human embryos. After six days of incubation, the osmotic pressure increased the most in Light 3.0 ml group. Heavy 4.5 ml group had the smallest change. However, no significant differences were noted in the formation rates of blastocysts, good-quality blastocysts, or cell count between the two groups. The study suggests that even when the culture medium is covered with heavy mineral oil in a dry incubator, osmotic pressure increases after six days but does not significantly affect the formation of blastocysts. These findings provide valuable insights into the effects of varying osmotic pressure on embryonic development and may help in optimizing conditions for in vitro fertilization.

Recently, mathematical and computational approaches have been incorporated into ICSI interventions as guiding tools. However, those tools carry no prognostic potential. Improving this capability may enhance ICSI attempts and assist clinicians working in infertility clinics. This study, thus aimed to investigate whether parental parameters could have predictive potential for the quality of resulting embryos with the ICSI approach using mathematical modelling techniques. Patient data including follicle number, MI and MII oocyte numbers, sperm number, sperm morphology and motility for 765 distinct couples attending British Cyprus IVF hospital was collected. Furthermore, morphological quality data as well as aneuploidy status for the 4123 resultant embryos were obtained. Regression analyses were conducted to observe the possible correlations between parental parameters and embryo quality and ploidy. Correlation analyses showed that follicle and oocyte numbers, as well as sperm parameters can be indicative of morphological quality of resulting embryos via ICSI (p values < 0.05). On the other hand, aneuploidy prediction remains too complicated to be predicted solely by these parameters (p values > 0.05). This study indicates a predictive potential of infertility measurements for male and female partners on ICSI success and is expected to act as a basis for the development of prognostic softwares to be used in IVF clinics.

In Western diets, high consumption of meat and dairy products, known to be rich in branched-chain amino acids (BCAAs), including leucine (Leu), isoleucine (Ile), and valine (Val), as well as BCAAs supplementation itself, may have unforeseen consequences on sperm quality. In addition, bodybuilders are increasingly resorting to BCAA supplementation to build-up their muscle mass. This study aimed to assess the effect of dietary BCAAs, provided alone or in combination, on semen parameters, apoptotic gene expression, and blood amino acid (AA) profiles. To address this question and determine whether these different BCAAs have a distinct impact on sperm quality and testicular homeostasis, fifty NMRI mature male mice were exposed or not to BCAAs supplementations (control diet: CTR; CTR + Leu supplementation; CTR + Ile supplementation; CTR + Val supplementation; CTR + all three BCAA supplementation). Only valine supplementation resulted in a significant decrease in sperm concentration and viability. In addition, only valine supplementation was associated with a dramatic increase in sperm immotility. The Bax/Bcl2 ratio, an indicator of apoptosis, was found to be significantly higher in the testes of BCAA-supplemented animals when compared with the other groups. Caspase3 expression was also significantly higher in the testes of BCAA-supplemented and Val-supplemented animals. There were no significant differences in plasma AA profiles between groups. Thus, amongst BCAAs, valine supplementation appears to carry the greatest effect on sperm functional parameters and testicular apoptotic status.

During embryogenesis in Danio rerio (zebrafish), the earliest morphological patterning events are dependent on the precise temporal translation and/or localization of specific maternal mRNAs/proteins. Dorsoventral patterning in particular requires the translocation of maternal factors that are present in the Balbiani Body from the vegetal region of the unfertilized egg to the future dorsal side of the embryo (Fuentes et al., 2020), leading to the localized activation of the β-catenin pathway in the cells in that region. Since zebrafish are chordates, this dorsoventral patterning then leads to the formation of neural tissue on the dorsal side of the embryo. What is not yet clear is the identity of all maternal and zygotic factors that first establish dorsoventral patterning, and which factors lead to the establishment of neural versus non-neural tissue. Taking an evolutionary approach to this question, we investigated a gene in zebrafish, zsquidlike-A (hnrnpaba), that is homologous to a key dorsoventral patterning gene in fruit flies (Drosophila melanogaster) called squid (Kelley, 1993). While dorsoventral patterning in flies and fish looks quite different both morphologically and at the molecular level, we demonstrate that not only has a key dorsoventral patterning gene in flies been conserved in fish, maternal fish zsquidlike-A protein is synthesized precisely as dorsoventral patterning is unfolding in fish embryos, and in its absence, dorsoventral patterning is severely disrupted.

Sesquizygotic twinning (SZT) is one of the rarest events that can occur in multiple pregnancies. It has only been reported twice to date. Studies indicate that sesquizygotic twins result from the splitting of a chimeric embryo at an early stage. Theories and studies suggest that SZT represents a third unique twinning mechanism that is different from dizygotic and monozygotic twinning; however, the unique features of SZT have nothing to do with the twinning mechanism. Instead, it resembles more of an atypical monozygotic twinning form according to the twinning mechanism.

The objective of this cohort study was to investigate whether embryo quality and morphokinetic behaviour differ in the four groups of low-prognosis women as stratified by the POSEIDON criteria. The study was performed in a private university-affiliated in vitro fertilization (IVF) centre, and included 3326 injected oocytes from 846 women undergoing ICSI cycles between March 2019 and April 2022. Kinetic markers from the point of insemination were recorded in the EmbryoScope incubator. Generalized mixed models followed by Bonferroni post hoc were used to compare morphokinetics among the POSEIDON groups. Embryos derived from patients in the POSEIDON groups 2, 3 and 4 showed significantly slower divisions compared to those from POSEIDON 1 group. The KIDScore rank was significantly lower for embryos deriving from POSEIDON groups 2, 3 and 4 (2: 4.4 ± 0.7 vs. 3: 4.2 ± 0.2 vs. 4: 3.0 ± 0.4) compared to those deriving from POSEIDON 1 group (4.8 ± 0.1, p < 0.001). Group POSEIDON 1 showed improved implantation (26.9% vs. 2: 22.4% vs. 3: 20.0% vs. 4: 14.0, p < 0.001) and miscarriage rates (5.6% vs. 2: 31.2% vs. 4: 50.0%, p = 0.013). Embryo quality and morphokinetic behaviour differ across the POSEIDON groups, being more favourable in POSEIDON group 1, as well as implantation and miscarriage rates. Embryo development was more favourable in POSEIDON group 1 (young age and adequate ovarian reserve), suggesting that oocyte quality is determinant of embryo developmental potential. These findings show the reasonability of classifying POR by the POSEIDON criteria and provide information for counselling of POR regarding their possible prognosis.