Nanomaterials are increasingly used in manufacturing, medicine, consumer products, and environmental technologies due to their unique physicochemical properties. Although these materials offer substantial technological and societal benefits, their widespread use has raised concerns about potential health risks. Of particular importance is exposure during pregnancy, as certain nanoparticles can cross the placental barrier and reach the developing embryo. Fetal tissues are highly sensitive to environmental insults, so maternal exposure to nanoparticles may disrupt normal development and increase the risk of abnormal pregnancy outcomes. This review examines the current understanding of nanoparticle-induced developmental toxicity, with a focus on the vulnerability of the maternal–fetal unit. We discuss the structure and function of the placental barrier and the mechanisms that enable nanoparticle transfer from mother to fetus. Particular attention is given to how nanoparticle characteristics, including size, shape, composition, and surface chemistry, influence biodistribution, placental transport, tissue accumulation, and toxicity. We summarize the major molecular and cellular mechanisms implicated in fetotoxicity, highlighting oxidative stress, apoptosis, autophagy, and DNA damage as recurring pathways identified across experimental studies. These interconnected processes contribute to placental dysfunction, impaired fetal growth, developmental abnormalities, and adverse pregnancy outcomes. We also compare findings across different classes of nanoparticles, including metal, metal oxide, carbon-based, and polymeric nanomaterials, identifying both shared toxicological mechanisms and material-specific effects. Evidence from animal models demonstrates that susceptibility varies according to nanoparticle properties, exposure conditions, and species, underscoring the complexity of nanoparticle–biological interactions and the limitations of extrapolating experimental findings directly to humans. Overall, the available evidence indicates that nanoparticle exposure during pregnancy represents a potential risk to fetal health, although important knowledge gaps remain regarding human exposure and long-term developmental outcomes. A better understanding of the mechanisms underlying nanoparticle-induced fetotoxicity is essential for improving human health risk assessment, refining experimental models, informing regulatory policies, and supporting the safe-by-design development of nanomaterials. Such knowledge will help ensure the responsible application of nanotechnology while minimizing potential risks during pregnancy. Finally, this review is distinguished by its integrated analysis of how the chemical characteristics of nanoparticles govern placental transfer and the mechanistic pathways of fetotoxicity across multiple nanomaterial classes, providing a unified framework that connects material properties with their potential for abnormal fetal development and adverse pregnancy outcomes.

Assisted reproduction technology (ART) has advanced significantly over the past four decades, leading to improved pregnancy outcomes and a reduction in complications, particularly those associated with multiple pregnancies. These improvements largely stem from advances in understanding embryonic physiology, which has enabled better culture conditions. As a result, embryologists can now efficiently culture embryos to the blastocyst stage and successfully cryopreserve them for future use. However, while incubators aim to replicate the maternal environment of the oviduct and uterus, embryos in vitro are cultured in static conditions, unlike the dynamic, constantly changing environment they experience in vivo. Key factors such as pH, temperature, osmolality, and gas concentrations are crucial for establishing optimal embryo development and implantation potential. Moreover, the vitrification procedure for gametes or embryos can introduce oxidative stress, as well as osmotic shock and cryoprotectant toxicity, which may affect embryo viability and increase the risk of birth defects. Since the first successful ART birth in 1978, over 10 million babies have been conceived through these techniques. Although most of these children are healthy, concerns exist about potential birth defects or changes linked to the handling of gametes and embryos. The preimplantation period is marked by significant epigenetic reprogramming, which can be influenced by ART procedures such as ovarian stimulation, in vitro fertilization, embryo culture, and cryopreservation. However, the long-term health implications for offspring remain uncertain. Epigenetic reprogramming during early embryogenesis is essential for proper embryo development and can be changed by ART-related conditions. These concerns have raised questions about the possible connection between ART and a higher risk of birth defects or other changes in children born through these methods. Therefore, we conducted a scoping review following PRISMA-ScR guidelines to map evidence on ART-related risks, including epigenetic and birth defect outcomes.

In the last decades, to enhance success rates in assisted reproductive technology (ART) cycles, scientists have continually tried to optimize embryo culture and selection to increase clinical outcomes. In this scenario, the application of laser technology has increased considerably worldwide and is currently applied across ART in several ways: for assisted hatching (AH) or thinning of the zona pellucida (ZP), embryo biopsy, to immobilize and select the sperm during intracytoplasmic sperm injection, as well as to induce artificial blastocyst shrinkage before cryopreservation. Laser-AH has been suggested as a procedure to improve embryo implantation: the concept is that drilling holes through or thinning of the ZP could improve the hatching process and implantation. The artificial disruption of the ZP can be performed by different approaches: mechanically, chemically and with the laser, which is one of the most favourable and easy methods to remove part of the ZP and to augment the possibilities of implantation in patients defined as having a poor prognosis of success, or when the ZP is too thick. However, in the current literature, there is not sufficient evidence about the potential risk or impairment that laser utilization might induce on embryo development; therefore, the main aim of the current review is to provide an overview of the existing knowledge on the ZP and the mechanisms of manipulating it to improve the effectiveness of ART. Also, it emphasizes the positive aspect of laser application as a powerful tool that might increase the chance of pregnancy for infertile couples undergoing ART cycles.

Male infertility accounts for approximately 40% of infertility cases. There are many causes of male infertility, including environmental factors, age, lifestyle, infections, varicocele, and cancerous pathologies. Severe oligozoospermia, cryptozoospermia, and azoospermia (obstructive and non-obstructive) are identified as severe male factor infertility, once considered conditions of sterility. Today, in vitro fertilization (IVF) techniques are the only treatment strategy in cases of male factor infertility for which new methodologies have been developed in the manipulation of spermatozoa to achieve fertilization and increase success rates. This review is an update of in vitro manipulation techniques, in particular sperm selection, emphasizing clinical case-specific methodology. The success of an IVF process is related to infertility diagnosis, appropriate choice of treatment, and effective sperm preparation and selection. In fact, selecting the best spermatozoa to guarantee an optimal paternal heritage means increasing the blastulation, implantation, ongoing pregnancy and live birth rates, resulting in the greater success of IVF techniques.

Semen quality represents a compelling factor for fertility, and delineating the normal values has proven difficult. In the last four decades, several authors have reported a noticeable decline in sperm parameters. Also, studies investigating ‘time to pregnancy’ have shown that fecundity begins to be reduced when sperm numbers decrease below 30 million, even though according to the 6th edition of the WHO manual, the normal value is currently 16 million/mL or 39 million per ejaculate. There exists sufficient data to suggest a decline in sperm counts over time, even though the clear reason for this adverse trend is not well established, but some associations have been hypothesised, such as maternal smoking during pregnancy. Additional potential factors have yet to be fully illustrated but involve poor diet, increased obesity, and exposure to environmental toxins. Moreover, the change in environmental conditions and more common exposure to endocrine-disrupting chemicals (EDCs), such as pesticides and herbicides, as well as bisphenol A, phthalates, polychlorinated biphenyls, and heavy metals, starting from prenatal life and continuing into adulthood, may exhibit probable features explaining the reduction in sperm parameters. Therefore, the main goal of this narrative review is to furnish an overview of the possible effects of exposure to EDCs on testicular function and spermatogenesis and, also, to summarise the evidence regarding a decrease in sperm quality and examine its potential consequences.

Over the past 40 years there has been a worldwide critical change in the field of assisted reproduction technology (ART), leading to the increased application of single blastocyst transfer, which is extremely important to avoid the risks of multiple pregnancy and associated complications for both mother and babies. Indeed, advancements in ART over the last few decades have been obtained thanks to several improvements, including ovarian stimulation, embryo culture conditions and, of course, progress in cryopreservation methods, especially with the application of vitrification. The ability to cryopreserve human embryos has improved significantly with vitrification compared to the initially adopted slow-freezing procedures. Since the introduction of vitrification, it has become the gold standard method to effectively cryopreserve human blastocysts. However, some new protocols are now being explored, such as the short warming procedure and even shorter exposure to the equilibration solution before vitrification, which seem to provide optimal results. Therefore, the main aim of the current narrative review, will be to illustrate the benefit of vitrification as an effective method to cryopreserve the human blastocyst and to illustrate new protocols and variations which in future may increase the performance of vitrification protocols.

The implementation of next generation sequencing (NGS) in preimplantation genetic testing for aneuploidy (PGT-A) has led to a higher prevalence of mosaic diagnosis within the trophectoderm (TE) sample. Regardless, mosaicism could potentially increase the rate of live-born children with chromosomic syndromes, though available data from the transfer of embryos with putative PGT-A mosaicism are scarce but reassuring. Even with lower implantation and higher miscarriage rates, mosaic embryos can develop into healthy live births. Therefore, this urges an explanation for the disappearance of aneuploid cells throughout development, to provide guidance in the management of mosaicism in clinical practice. Technical overestimation of mosaicism, together with some sort of “self-correction” mechanisms during the early post-implantation stages, emerged as potential explanations. Unlike the animal model, in which the elimination of genetically abnormal cells from the future fetal lineage has been demonstrated, in human embryos this capability remains unverified even though the germ layer displays an aneuploidy-induced cell death lineage preference with higher rates of apoptosis in the inner cell mass (ICM) than in the TE cells. Moreover, the reported differential dynamics of cell proliferation and apoptosis between euploid, mosaic, and aneuploid embryos, together with pro-apoptosis gene products (cfDNA and mRNA) and extracellular vesicles identified in the blastocoel fluid, may support the hypothesis of apoptosis as a mechanism to purge the preimplantation embryo of aneuploid cells. Alternative hypotheses, like correction of aneuploidy by extrusion of a trisomy chromosome or by monosomic chromosome duplication, are even, though they represent an extremely rare phenomenon. On the other hand, the technical limitations of PGT-A analysis may lead to inaccuracy in embryo diagnoses, identifying as “mosaic” those embryos that are uniformly euploid or aneuploid. NGS assumption of “intermediate copy number profiles” as evidence of a mixture of euploid and aneuploid cells in a single biopsy has been reported to be poorly predictive in cases of mosaicism diagnosis. Additionally, the concordance found between the TE and the ICM in cases of TE biopsies displaying mosaicism is lower than expected, and it correlates differently depending on the type (whole chromosome versus segmental) and the level of mosaicism reported. Thus, in cases of low-/medium-level mosaicism (<50%), aneuploid cells would rarely involve the ICM and other regions. However, in high-level mosaics (≥50%), abnormal cells in the ICM should display higher prevalence, revealing more uniform aneuploidy in most embryos, representing a technical variation in the uniform aneuploidy range, and therefore might impair the live birth rate.

During recent decades, the application of intracytoplasmic sperm injection has increased considerably worldwide, especially in couples with non-male factor infertility. However, several studies analyzing the broad use of intracytoplasmic sperm injection, even in cases with a normal semen analysis, have collectively demonstrated no benefits compared to conventional in-vitro fertilization. Currently, there is insufficient evidence to support the intracytoplasmic sperm injection technique vs. in-vitro fertilization in cases of poor ovarian response or a low number of oocytes collected, or in patients with advanced maternal age. Since the intracytoplasmic sperm injection technique is more operator-dependent and invasive, its use should only be recommended in cases of male-factor infertility. There is some evidence showing that intracytoplasmic sperm injection is linked with an increased risk of birth defects. Albeit this evidence is limited, and currently it is not possible to draw a firm conclusion on these concerns, we do believe that these risks should be rigorously investigated. Thus, this review aims to clarify the debate on the application of the intracytoplasmic sperm injection procedure, as compared to standard in-vitro fertilization, in those assisted reproductive technology cycles without a clear male factor infertility. Furthermore, we try to clarify whether intracytoplasmic sperm injection would result in a higher live birth rate than in-vitro fertilization, in couples with non-male factor infertility.

Invasive and noninvasive features are normally applied to select developmentally competent oocytes and embryos that can increase the take-home baby rates in assisted reproductive technology. The noninvasive approach mainly applied to determine oocyte and embryo competence has been, since the early days of IVF, the morphological evaluation of the mature cumulus-oocyte complex at the time of pickup, first polar body, zona pellucida thickness, perivitelline space and cytoplasm appearance. Morphological evaluation of oocyte quality is one of the options used to predict successful fertilization, early embryo development, uterine implantation and the capacity of an embryo to generate a healthy pregnancy to term. Thus, this paper aims to provide an analytical revision of the current literature relating to the correlation between ovarian stimulation procedures and oocyte/embryo quality. In detail, several aspects of oocyte quality such as morphological features, oocyte competence and its surrounding environment will be discussed. In addition, the main noninvasive features as well as novel approaches to biomechanical parameters of oocytes that might be correlated with the competence of embryos to produce a healthy pregnancy and live birth will be illustrated.

BACKGROUND:Despite being marketed as "sperm friendly", some vaginal lubricants are known to be detrimental to sperm function and therefore could negatively affect fertility. Many others have not yet been assessed in regards to their effect on sperm function. This issue may concern couples trying to conceive both naturally and via artificial reproductive technologies (ART).AIM:The aim of this research was to analyse the effects that lubricants, commonly used in the setting of natural conception and ART, have on sperm function in an in vitro setting. This was done by assessing sperm motility, vitality and DNA fragmentation following treatment with commercial lubricants or control preparations. We have attempted to mimic the conditions of the vaginal environment in our clinical trial, and so have compiled a list of lubricants that are likely to have minimal negative effect on sperm function in vivo or are "sperm friendly".METHODS:Ten samples were obtained for the study from patients attending a fertility clinic. Once collected, the sperm samples were prepared by density gradient centrifugation and incubated with 11 different lubricants including positive and negative controls for 30 min at 37 °C to mimic the temperature inside the female reproductive tract. Sperm motility, vitality and DNA fragmentation were assessed to determine the effects of the lubricants on sperm function and DNA integrity.RESULTS:Nine lubricants were investigated including Sylk™, Conceive Plus®, glycerol, Johnson's® Baby Oil, SAGE® Culture Oil, Yes®, Forelife™, MaybeBaby® and Pre-seed®. The lubricant which had the best results in terms of vitality, at 92%, was Pre-seed® and the worst was Forelife™ with 28% vitality. In terms of motility, Pre-seed® resulted in the highest percentage of spermatozoa with progressive motility at 86% and Sylk™ resulted in the lowest percentage of progressively motile cells in the sample with 31% of sperm progressively motile. There were no significant effects on DNA integrity.CONCLUSIONS:Pre-seed® was the lubricant which had the least negative effect on sperm function, with Conceive Plus® a close second, due to the significantly higher sperm motility and vitality parameters measured following lubricant exposure.

OBJECTIVE:To report the first live births of male infants resulting from intracytoplasmic sperm injection (ICSI) using spermatozoa from a man with Eagle-Barrett syndrome (EBS). DESIGN:Case report. SETTING:Assisted conception unit within a private hospital. PATIENT(S):An infertile couple. INTERVENTIONS:An infertile couple received repeated treatment with ICSI. MAIN OUTCOME MEASURE(S):Clinical pregnancy and a normal live birth. RESULT(S):In 2008, after microinjection of ten oocytes, the transfer of a single expanded blastocyst led to the premature birth of a morphologically normal male infant at 18 weeks' gestation. This outcome followed preterm rupture of membranes and possible cervical incompetence. In 2009, after microinjection of six oocytes, transfer of a single 5-cell embryo led to a singleton pregnancy, with emergency cervical cerclage being performed at 21 weeks. A healthy male infant was born at 30 weeks, with no evidence of EBS, by lower-segment cesarean section for breech presentation and premature labor. In 2012, after elective laparoscopic placement of cervical suture, microinjection of ten oocytes and transfer of a single 4-cell embryo led to a singleton pregnancy with a healthy male infant, with no evidence of EBS, being born by cesarean section at 38 weeks. CONCLUSION(S):This report suggests that EBS is not transmitted to male offspring via ICSI.

Background: Postoperative assessment after varicocele surgery in adolescence is commonly centred around catch-up growth of the testis. There is paucity of evidence on the correlation of catch-up growth with underlying testicular function in these patients.Aims: To assess the reliability of catch-up growth of the testis as an indicator of normalization of testicular function and the utility of serum FSH levels in the long-term postoperative assessment of varicocele surgery in adolescence.Materials and Methods: Prospective cohort study of young adults (18-27 years) who had laparoscopic varicocele correction in adolescence (11-16 years). Evaluation included serum FSH levels, scrotal ultrasonography and semen analysis.Analysis: Anatomical and functional parameters of participants with equal and normal testicular size were compared to those of participants with persistent testicular hypotrophy or hypertrophy. Sensitivity and positive predictive value of postoperative serum FSH levels were estimated and elevated levels of serum FSH were checked for association with suboptimal outcomes of varicocele correction.Results: The serum FSH levels of participants with unequal testicular sizes (n=6, median 6.65 IU/l), which included testicular hypertrophy (n=3, median 7.2 IU/l) and persistent testicular hypotrophy (n=3, median 6.1 IU/l), were significantly higher than the group with equal testicular sizes (n=8, median 3.5 IU/l; P=0.014, Mann-Whitney U test). Postoperative elevated serum FSH levels were significantly associated with suboptimal outcomes of varicocele surgery (P=0.015, Fishers exact test). The test also had a high positive predictive value.Conclusions: Testicular catch-up growth may not be a reliable postoperative assessment criterion by itself. Serum FSH levels may be of value in detecting suboptimal outcomes of varicocele surgery in adolescents.