Effect of cytoplasmic fragmentation on embryo development, quality, and pregnancy outcome: a systematic review of the literature.

The role of cytoplasmic fragmentation in human embryo development and reproductive potential is widely recognized, albeit without standard definition nor agreed upon implication. While fragmentation is best understood to be a natural process across species, the origin of fragmentation remains incompletely understood and likely multifactorial. Several factors including embryo culture condition, gamete quality, aneuploidy, and abnormal cytokinesis seem to have important role in the etiology of cytoplasmic fragmentation. Fragmentation reduces the volume of cytoplasm and depletes embryo of essential organelles and regulatory proteins, compromising the developmental potential of the embryo. While it has been shown that degree of fragmentation and embryo implantation potential are inversely proportional, the degree, pattern, and distribution of fragmentation as it relates to pregnancy outcome is debated in the literature. This review highlights some of the challenges in analysis of fragmentation, while revealing trends in our evolving knowledge of how fragmentation may relate to functional development of the human embryos, implantation, and pregnancy outcome.

Chronic demyelination interferes with normal spermatogenesis in cuprizone-intoxicant C57/BL 6 mice: An experimental study.

Background: Due to myelin and axonal insults in multiple sclerosis individuals, motor coordination problems and endocrine imbalance may develop. Objective: This study aims to evaluate the role of chronic demyelination on the hypothalamic-pituitary-gonadal axis in the mouse model of multiple sclerosis. Materials and Methods: 20 adult C57/BL6 male mice were divided into 2 groups (n = 10/each) as follows: the control group (CONT) received a regular diet for 17 wk; and the experimental group (cuprizone [CPZ]) was fed with 0.2% CPZ for 12 wk and, then CPZ was withdrawn for 5 wk. Serum testosterone, histopathology of the brain and testis, and sperm analysis were evaluated. Results: The hypothalamic myelin content was significantly decreased in the arcuate nucleus following the 12 wk of CPZ consumption compared to the CONT group, and the statistical difference remained until 17 wk. Testosterone levels declined significantly in the CPZ group compared to the CONT group in the 12 th and 17 th wk. A significant decrease was observed in the height of the seminiferous epithelium and the interstitial tissue area, and the number of seminiferous epithelial cells in the CPZ group compared to the CONT group in the 12 th and 17 th wk. The sperm count, motility, and viability in the CPZ group significantly decreased compared to the CONT group in the 12 th and 17 th wk of the study. Conclusion: Chronic demyelination induced by CPZ intoxication, maybe through damage to the hypothalamus arcuate nucleus, leads to the hypothalamic-pituitary-gonadal axis disturbance and damage to the testis and spermatogenesis subsequently.

Effect of Conditioned Medium from Human Adipose-Derived Mesenchymal Stem Cells on Human Sperm Quality During Cryopreservation.

The cryopreservation procedure decreases sperm quality, causing certain changes at structural and molecular levels affecting fertilizing ability. We aimed to investigate the impacts of human adipose-derived mesenchymal stem cells (HAd-MSCs) conditioned medium (CM) on the protection of human sperm from cryoinjury. Thirty normal semen specimens were evaluated in this study. Each specimen was separated into six groups and enhanced with varying concentrations of human Ad-MSCs-CM (0, 10, 30, 50, 70, and 100%). Sperm motility, viability, morphology, apoptosis, mitochondrial potential, and lipid peroxidation, and DNA fragmentation were evaluated before freezing and after thawing. The results showed that the total motility was preserved in 10% human Ad-MSCs-CM group. Also, DNA fragmentation was significantly lower in 10% compared to 0% human Ad-MSCs-CM (63.62 ± 17.72% vs.76.46 ± 4.87%, respectively, P < 0.004). Human Ad-MSCs-CM in groups of 10, 30, 50, and 70% reduced lipid peroxidation. The normal sperm morphology rate, mitochondrial membrane potential, and apoptosis showed no significant differences across various groups. It seems that human Ad-MSCs-CM can protect the sperm parameters during the cryopreservation by decreasing cryoinjury.

Evaluation of the effects of hydroxytyrosol on human sperm parameters during cryopreservation.

Human sperm cryopreservation is a routine procedure in assisted reproductive technology, but it has detrimental effects on different sperm parameters due to oxidative stress. Our objective was to assess the impacts of hydroxytyrosol (HT), as an antioxidant, on human sperm parameters following cryopreservation. In the first phase, 20 normal human semen samples were cryopreserved using the rapid freezing method with different concentrations of HT including 0, 50, 100, 150, and 200 µg/mL. In the second phase, 20 normal semen samples were collected and cryopreserved with 50 and 100 µg/mL HT. The beneficial effects of HT were determined by evaluation of motility (computer-assisted sperm analysis; CASA), viability (Eosin-nigrosine stain), DNA integrity (sperm chromatic dispersion test, SCD), reactive oxygen species (DCF and DHE staining by flowcytometry) lipid peroxidation (malondialdehyde, MDA test) and mitochondrial membrane potential (JC1 staining by flowcytometry) of sperm after cryopreservation. After thawing, sperm motility had an increasing trend in 50 and 100 µg/mL HT groups in comparison with other groups, althought the difference was not significant. However, sperm viability was significantly increased at 50 and 100 µg/mL HT. Our data also showed that sperm DNA fragmentation was significantly decreased after thawing at 100 µg/mL in comparison with 0 and 50 µg/mL HT. However, the level of intracellular reactive oxygen species, lipid peroxidation and mitochondrial membrane potential were not significantly different between groups. Our results showed that HT may have protective effects on the viability and DNA integrity of human sperm during the freezing-thawing process.

High-DNA integrity sperm selection using rheotaxis and boundary following behavior in a microfluidic chip.

Rheotaxis, as one of the main natural guidance mechanisms in vivo, has been used in microfluidics to separate motile sperm. However, the lack of DNA integrity assessment and the inability to separate the cells in a specific reservoir have been the main limitations for the practical application of most of the devices using rheotaxis for sperm separation. Here, we present a microfluidic chip that can separate highly motile sperm using their inherent rheotaxis and boundary-following behavior in a network of boomerang-shaped microchannels. The device design is informed by our FEM simulation results to predict sperm trajectories. Experimental results demonstrate the device's performance to separate over 16 000 motile sperm in under 20 min, sufficient for droplet-based IVF. Separated cells are classified into two motility groups, highly motile (swimming speed > 120 µm s-1) and motile (swimming speed < 120 µm s-1). The device selects sperm with over 45%, 20%, and 80% improvement in motility, the number of highly motile sperm, and DNA integrity, respectively, suggesting promising potential for applications in assisted reproduction.

In vitro effects of plasma rich in growth factors on human teratozoospermic semen samples.

There is a correlation between teratozoospermia and production of reactive oxygen species leading to poor assisted reproductive techniques outcomes. This study aimed to examine the effect of plasma-rich in growth factors (PRGF) on teratozoospermic samples. Twenty-five teratozoospermic samples were included in this study. After sperm preparation, it was divided into four groups, including 0 (control), 1, 5, and 10% PRGF. Sperm motility, viability (eosin-nigrosin staining), morphology (Papanicolaou staining), DNA fragmentation (sperm chromatin dispersion test), mitochondrial membrane potential (JC-1 staining by flow cytometry), and lipid peroxidation (measurement of malondialdehyde, MDA) were evaluated before and after 1 h of incubation with or without PRGF. Our results showed that after 1 h of incubation, the addition of 1% PRGF improved sperm progressive motility (47.72 ± 13.76%) compared to the control group (17.36 ± 8.50%) (p < 0.001). Also, 1% PRGF preserved the sperm's total motility (77.50 ± 13.28% vs. 65.63 ± 19.03%, for 1% PRGF and control, respectively) and viability after incubation. The rate of normal sperm morphology was the same between different groups. Higher mitochondrial membrane potential and lower DNA fragmentation were also observed in sperm treated with different concentrations of PRGF compared to the control group, but the differences were non-significant. The MDA levels were significantly decreased in PRGF-treated groups compared to the control group (0.99 ± 0.62, 0.95 ± 0.33, 0.95 ± 0.79, and 1.49 ± 0.27 for 1% PRGF, 5% PRGF, 10% PRGF and control, respectively). Based on our results, it seems that PRGF incubation can improve sperm parameters and especially decrease the level of malondialdehyde as an indicator of oxidative stress, which is one of the main problems of teratozoospermic samples.

A novel microfluidic device with parallel channels for sperm separation using spermatozoa intrinsic behaviors.

Isolating high-quality motile sperm cells is considered to be the main prerequisite for a successful artificial pregnancy. Microfluidics has emerged as a promising platform capable of mimicking in-vivo environments to separate motile sperm cells and bypassing the need for the current invasive clinical sperm separation methods. In this study, the proposed microfluidic device exploits the parallelization concept through symmetry to increase both the processed sample volume and the injected flow rate compared with the previous conventional devices, which used rheotaxis as their primary method of sperm separation. Using the finite element method (FEM) and flow simulations, the trajectories of sperm cells exhibiting rheotaxis behavior were predicted inside the proposed device. Different flow rates, including 0, 0.5, 1.5, 3, 4.5 and 6 µl/min, were experimentally injected into the device, and the effect of flow rate on the size of the hypothetical rheotaxis zone and the number of isolated sperm cells was investigated. Furthermore, it was illustrated that 100% of the isolated motile sperm cells are motile, and by manipulating the injected flow rate into the device, different classes of sperm cells in terms of motility parameters can be separated and utilized for further uses.

In vitro differentiation of primed human induced pluripotent stem cells into primordial germ cell-like cells.

BACKGROUND: Previous studies have shown significant results in the differentiation of mouse-induced pluripotent stem cells (miPSCs) into primordial germ cell-like cells (PGCLCs) and that human iPSCs (hiPSCs) can also differentiate into PGCLCs; however, the efficiency of PGCLC induction from hiPSCs is < 5%. In this study, we examined a new protocol to differentiate hiPSCs into PGCLCs. METHODS AND RESULTS: hiPSCs-derived embryoid bodies (EBs) were exposed to differentiate inducing factors, bone morphogenetic protein 4 (BMP4), and retinoic acid (RA) for 6 days. Cell differentiation was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR) and immunofluorescence (IF) studies. Our results showed increased expression of the PRDM1 gene on the first day of differentiation. On other days, DAZL, VASA, and STRA8 genes increased, and the expression of PRDM1, NANOG, and OCT4 genes decreased. The expression of VASA, C-KIT, and STRA8 proteins was confirmed by IF. A flow cytometry analysis revealed that ~ 60% of differentiated cells were VASA- and STRA8-positive. CONCLUSION: EB formation and constant exposure of EBs to BMP4 and RA lead to the differentiation of hiPSCs into PGCLCs.

Ultrastructure of human ovarian tissues and risk of cancer cells re-implantation after transplantation to chick embryo chorioallantois membrane (CAM) following vitrification or slow freezing.

Ovarian follicle depletion and premature ovarian failure are significant challenges in cancer patients subjected to radio- or chemotherapy. Ovarian tissue (OT) cryopreservation would be an option when other fertility preservation methods are not accessible. This study aimed to analyze the structure and ultrastructure of human OTs transplanted onto chick embryo chorioallantois membrane (CAM) after cryopreservation by vitrification or slow freezing. OTs from 10 cancer patients underwent cryopreservation. CAM transplantation was done on fresh and cryopreserved OTs, to assign samples to nine study groups as follows: 1) FI-FIII = fresh, 5- and 10-days post-CAM transplantation groups; 2) VI-VIII = vitrified, 5- and 10-days post-transplantation vitrified groups; 3) SFI-SFIII: slow frozen, 5- and 10-days post-transplantation slow freezing groups. Proliferation ability, folliculogenesis, and structural and ultrastructure were analyzed. The density of primordial follicles did not change after both freezing methods, but reduced after 5 (P ≥ 0.05) and 10 days (P ≤ 0.05) post-CAM transplantation. The follicular grade significantly decreased in all transplanted tissues (P ≤ 0.0). The proliferation marker increased after cryopreservation, but reduced after transplantation (P ≤ 0.05). TEM evaluation showed better follicular ultrastructure in the fresh group, after transplantation. Stromal ultrastructure appeared more preserved after vitrification compared with slow freezing. There was no sign of malignant cell contamination after transplantation. Some follicular TEM abnormalities were found in both methods of freezing, with a better transplantation rate after vitrification. Also, enhanced follicular activation resulted in faster follicular depletion in this method. The information regarding post grafting events would improve our knowledge for longer OTs' lifespans.

The role of growth factors in human sperm parameters: A review of in vitro studies.

In vitro sperm preparation/incubation and cryopreservation are associated with oxidative stress as the main cause of sperm damage, and different strategies are used to improve sperm quality in in vitro conditions to treat male infertility. Growth factors (GFs) are biological molecules that play different roles in various cellular processes such as growth, proliferation, and differentiation. Many studies have shown that GFs and their receptors are expressed in the male reproductive system. In vitro supplementation of GFs to improve sperm parameters has yielded useful results. There are many studies on the effects of GFs on sperm quality improvement and subsequent assisted reproductive technology results. Hence, this study will review the in vitro results of various GFs including brain-derived neurotrophic factor, nerve growth factor, fibroblast growth factor, insulin-like growth factor I, and vascular endothelial growth factor to improve sperm quality.

Alginate Effects on Human Sperm Parameters during Freezing and Thawing: A Prospective Study.

OBJECTIVE: The main goal was to evaluate the effects of alginate on human sperm parameters during cryopreservation. MATERIALS AND METHODS: In this prospective study, twenty-five normozoospermic samples were divided into two groups, encapsulated with 1% alginate and the control group. The samples were then frozen by rapid freezing. Different sperm parameters including motility, normal morphology, viability, acrosome reaction, and DNA integrity, were examined before freezing and after thawing. RESULTS: All sperm parameters had a significant decrease after thawing compared to before freezing. Our data showed a significant decrease in sperm motility of the alginate group but sperm viability, normal morphology, and DNA fragmentation were similar between the two groups. However, the rates of intact acrosome and native DNA were significantly lower in the control group compared to the alginate group (45.12 ± 11.1 vs. 55.25 ± 10.69 and 52.2 ± 11.92 vs. 68.12 ± 10.15, respectively, P<0.05). CONCLUSION: It seems that alginate can prevent premature acrosome reaction and protect sperm DNA from denaturation during the rapid freezing process.

A novel microfluidic system to separate sperm using spermatozoa inherent motion and inertial effect.

Sperm separation is an essential part of in vitro fertilization (IVF) process. In conventional procedures, the semen sample is purified from immotile and round cells using centrifugation, which may damage sperm DNA. This study aimed to design a novel microchip to separate the progressively motile spermatozoa using a passive method instead of centrifugation. This microchip is a novel, non-invasive, and two-stage device for auto-selecting the sperm used for IVF. The first stage was designed based on lateral differentiation and rapid divergence to separate the pathways of sperm and round cells. The second stage separates high-quality sperm based on their inherent motion. Before experimenting with fresh human semen samples, preliminary tests were performed using standard particles. The results showed that at the optimized flow rate for separation (1.7 ml/h), the concentration of progressively motile spermatozoa at outlet was significantly increased compared with the initial sample.

Plasma-Rich in Growth Factors Ameliorates Detrimental Effects of Cryopreservation on Human Sperm: A Prospective Study.

Objective: Sperm cryopreservation results in damage to membrane integrity, sperm viability, sperm motility, and DNA structure. We aimed to evaluate the effect of plasma rich in growth factors (PRGF) on sperm parameters during the freeze-thaw process. Materials and Methods: In the first phase of this prospective study, after sperm preparation, 10 normozoospermic specimens were cryopreserved by rapid freezing with different concentrations of PRGF including 0, 1, 5, and 10% to find the optimum dose. Sperm motility and viability were assessed in this phase. In the second phase of the study, based on the results of first phase, 25 normal sperm samples were frozen with 1% PRGF. All sperm parameters including motility, viability, acrosome reaction, and DNA integrity were assessed before freezing and after thawing. Results: The rates of progressive and total sperm motility and viability were significantly higher in 1% PRGF compared to control, 5%, and 10% PRGF in the first phase (P<0.05). Supplementation of freezing medium with 1% PRGF could significantly improve all sperm parameters including sperm motility, viability, normal morphology, acrosome integrity, chromatin structure, chromatin integrity, DNA denaturation, and DNA fragmentation in comparison with the control group. Conclusion: It appears that the supplementation of freezing medium with 1% PRGF could protect human sperm parameters during cryopreservation.

Trehalose Attenuates Detrimental Effects of Freeze-Drying on Human Sperm Parameters.

Freeze-drying is one of the sperm preservation methods leading to the long-term preservation of sperm genetic material. Our main goal of this study was to evaluate the effect of the trehalose freeze-drying method on sperm motility, viability, morphology, acrosome, and DNA integrity compared with a standard protocol without trehalose. Twenty-five normozoospermic samples were included in this prospective study. Direct swim-up was used for sperm preparation. An experiment was performed on freeze-dried samples containing trehalose (0.2 M), and the results were compared to that without trehalose. The sperm parameters, including count, motility, morphology, viability, acrosome reaction, DNA denaturation, and DNA fragmentation, were evaluated before and after freeze-drying in both groups. The spermatozoa were totally immotile after freeze-drying in both groups. Sperm viability, acrosome integrity, and nondenatured sperm DNA were significantly higher in the trehalose group in comparison with that of without trehalose group. Nonfragmented sperm DNA showed an increasing trend in the trehalose group compared to the group without trehalose. While freeze-drying significantly reduced normal morphology, the addition of trehalose did not affect this parameter. The results of this study showed that trehalose can attenuate the detrimental effects of freeze-drying on human sperm parameters.

The exact synchronization timing between the cleavage embryo stage and duration of progesterone therapy-improved pregnancy rates in frozen embryo transfer cycles: A cross-sectional study.

BACKGROUND: Synchronization between the embryonic stage and the uterine endometrial lining is important in the outcomes of the vitrified-warmed embryo transfer (ET) cycles. OBJECTIVE: The aim was to investigate the effect of the exact synchronization between the cleavage stage of embryos and the duration of progesterone administration on the improvement of clinical outcomes in frozen embryo transfer (FET) cycles. MATERIALS AND METHODS: 312 FET cycles were categorized into two groups: (A) day-3 ET after three days of progesterone administration (n = 177) and (B) day-2 or -4 ET after three days of progesterone administration (n = 135). Group B was further divided into two subgroups: B1: day-2 ET cycles, that the stage of embryos were less than the administrated progesterone and B2: day-4 ET cycles, that the stage of embryos were more than the administrated progesterone. The clinical outcome measures were compared between the groups. RESULTS: The pregnancy outcomes between groups A and B showed a significant differences in the chemical (40.1% vs 27.4%; p = 0.010) and clinical pregnancies (32.8% vs 22.2%; p = 0.040), respectively. The rate of miscarriage tended to be higher and live birth rate tended to be lower in group B than in group A. Also, significantly higher rates were noted in chemical pregnancy, clinical pregnancy, and live birth in group A when compared with subgroup B2. CONCLUSION: Higher rates of pregnancy and live birth were achieved in day-3 ET after three days of progesterone administration in FET cycles.

Impairment of sperm efficiency in mice following short-term nano-titanium dioxide exposure: An experimental study.

BACKGROUND: Titanium dioxide nanoparticles (TiO 2 NPs) are widely used in many compounds. Recent evidence has displayed some cytotoxic effects of TiO 2 NPs on male reproduction. OBJECTIVE: The effects of TiO 2 NP administration on sperm parameters and chromatin and seminiferous histopathology of male mice were investigated. MATERIALS AND METHODS: In this experimental study, 32 NMRI male mice (35 ± 3 gr, 8-12-week-old) were divided into four groups (n = 8/each): treated groups were fed orally with 2.5 (group I), 5 (group II) and 10 (group III) mg/kg/day TiO 2 NPs for 40 days and the control group received phosphate buffered saline. Sperm parameters, DNA integrity and chromatin quality were assessed using chromomycin A3, aniline blue, toluidine blue staining and TUNEL. Hematoxylin eosin staining was performed to measure spermatogenic cells and the total diameter of seminiferous tubules. Also, sex hormone and malondyaldehyde levels were measured. RESULTS: Abnormal sperm tails rose in group III (28.87 ± 4.91) in comparison with the control group (12.75 ± 3.95). However, chromomycin A3 staining and TUNEL showed higher levels in group III in comparison with the control group, whereas aniline blue and toluidine blue staining showed no differences. A significantly lower spermatogenesis index and lumen parameters were observed in group III. Leydig cell numbers, cellular diameters and the area of the seminiferous tubules were lower in the treated groups. The testosterone level was also lower in these groups and the percentage of malondyaldehyde in the seminal fluid was higher. CONCLUSION: Exact mechanisms of TiO 2 NPs are not clear; however, cytotoxic and genotoxic effects of TiO 2 NPs may relate to oxidative stress. Given their widespread use, TiO 2 NPs should be a public health focus of attention.

Formation of organoid-like structures in the decellularized rat testis.

Objectives: In testis, the extracellular matrix (ECM) in addition to the supportive role for cells in the seminiferous epithelium, is also essential for the accurate functioning of these cells. Thus, using a decellularized testicular ECM (DTECM), as a scaffold for three-dimensional (3D) culture of testicular cells can mimic native ECM for studying in vitro spermatogenesis. Materials and Methods: The rat testis was decellularized via perfusion of 0.5% sodium dodecyl sulfate (SDS) for 48 hr, followed by 1% Triton X-100 for 6 hr, and then 1% DNase I for 1 hr. The efficiency of decellularization was evaluated by histology, immunohistochemistry (IHC), scanning electron microscopy (SEM), and MTT test. The prepared scaffolds were recellularized with testicular cells and cultured and assessed with hematoxylin-eosin (H&E) staining after two weeks. Results: Based on the H&E image, no trace of cell components could be observed in DTECM. IHC images demonstrated collagen types I and IV, laminin, and fibronectin were preserved. Masson's trichrome and alcian blue staining revealed that collagen and glycosaminoglycans (GAGs) were retained, and the SEM image indicated that 3D testicular architecture remained after the decellularization process. Based on the results of the MTT test, DTECM was cytocompatible, and H&E images represented that DTECM supports testicular cell arrangements in seminiferous tubule-like structures (STLSs) and organoid-like structures (OLSs). Conclusion: The results showed that the applied protocol successfully decellularized the testis tissue of the rat. Therefore, these scaffolds may provide an appropriate vehicle for in vitro reconstruction of the seminiferous tubule.

Advanced paternal age: effects on sperm parameters, assisted reproduction outcomes and offspring health.

Many factors, including postponement of marriage, increased life expectancy, and improved success with assisted reproductive technologies have been contributing to increased paternal age in developed nations. This increased average paternal age has led to concerns about adverse effects of advanced paternal age on sperm quality, assisted reproductive outcomes, and the health of the offspring conceived by older fathers. This review discusses the association between advanced paternal age and sperm parameters, assisted reproduction success rates, and offspring health.

The efficacy of antioxidants in sperm parameters and production of reactive oxygen species levels during the freeze-thaw process: A systematic review and meta-analysis.

To investigate the impact of antioxidants in sperm parameters and reduction in reactive oxygen species production during the freeze-thaw process. PubMed, Scopus, Web of Science, Embase and Cochrane central library were systematically searched. Of the 1583 articles, 23 studies were selected for data extraction. Our results show that antioxidants improved sperm progressive motility (standardised mean difference (SMD) = 1; 95% CI: 0.62, 1.38; p < .001) and viability (SMD = 1.20; 95% CI: 0.50, 1.91; p = .001) and reduced sperm DNA fragmentation (SDF) and hydrogen peroxide (H2 O2 ) production, but there was no significant improvement in total sperm motility after thawing. Acetyl-l-carnitine/l-carnitine, melatonin and catalase had a significant positive impact on progressive motility. The role of tempol and melatonin in improving viability was significant compared to other antioxidants. Moreover, a significant reduction in SDF was observed after addition of butylated hydroxytoluene, tempol and vitamin E. However, the prevention of H2 O2 production was significant only after the addition of tempol. Our overall results displayed the positive impact of antioxidants on progressive sperm motility, viability and reduction in SDF and H2 O2 production, but no significant impact of antioxidants on total sperm motility was seen during the freeze-thaw process.

Quality of Blastocysts Created by Embryo Splitting: A Time-Lapse Monitoring and Chromosomal Aneuploidy Study.

OBJECTIVE: The aim of this study was to screen the potential of human embryos to develop into expanding blastocysts following in vitro embryo splitting and then assess the quality of the generated blastocysts based on chromosomal characteristics and using morphokinetics. MATERIALS AND METHODS: In this experimental study, a total of 82 good quality cleavage-stage donated embryos (8- 14 cells) were used (24 embryos were cultured to the blastocyst stage as controls and 58 embryos underwent in vitro splitting). After in vitro splitting, the blastomere donor and blastomere recipient embryos were named twin A and twin B, respectively. Morphokinetics and morphological parameters were evaluated using a time-lapse system in the blastocysts developed from twin embryos. Aneuploidy of chromosomes 13, 15, 16, 18, 21, 22, X and Y were analyzed in the twin blastocysts. RESULTS: Following in vitro splitting, of the 116 resulting twin embryos, 80 (69%) developed to the expanded blastocyst (EBL) stage compared to 21 (87.5%) embryos in the control group (P>0.05). The morphokinetics analysis suggested that the developmental time-points were influenced by the in vitro splitting. Moreover, the blastocysts developed from A and B twins had impaired morphology compared to controls. Regarding chromosome abnormalities, there was no significant difference in the rate of aneuploidy or mosaicism between the different groups. CONCLUSION: This study showed that while no chromosomal abnormalities were seen, in vitro embryo splitting may affect the embryo morphokinetics.