Summary The process of embryonic development is crucial and radically influences preimplantation embryo competence. It involves oocyte maturation, fertilization, cell division and blastulation and is characterized by different key phases that have major influences on embryo quality. Each stage of the process of preimplantation embryonic development is led by important signalling pathways that include very many regulatory molecules, such as primary and secondary messengers. Many studies, both in vivo and in vitro, have shown the importance of the contribution of reactive oxygen species (ROS) as important second messengers in embryo development. ROS may originate from embryo metabolism and/or oocyte/embryo surroundings, and their effect on embryonic development is highly variable, depending on the needs of the embryo at each stage of development and on their environment (in vivo or under in vitro culture conditions). Other studies have also shown the deleterious effects of ROS in embryo development, when cellular tissue production overwhelms antioxidant production, leading to oxidative stress. This stress is known to be the cause of many cellular alterations, such as protein, lipid, and DNA damage. Considering that the same ROS level can have a deleterious effect on the fertilizing oocyte or embryo at certain stages, and a positive effect at another stage of the development process, further studies need to be carried out to determine the rate of ROS that benefits the embryo and from what rate it starts to be harmful, this measured at each key phase of embryonic development.

Summary The process of oocyte retrieval represents a key phase during the cycles of in vitro fertilization (IVF). It involves controlled ovarian stimulation to retrieve the highest number of oocytes possible. According to many previous studies, the higher the number of oocytes the higher the chances of obtaining embryos for multiple transfers. In this study, in total, 1987 patients were retrospectively reviewed to investigate the correlations between the number of retrieved oocytes and the subsequent IVF outcomes. Patients were divided into three groups according to the number of retrieved oocytes (Group 1: ≤5 oocytes; Group 2: 6–15 oocytes; Group 3: ≥15 oocytes). The results showed a significant negative correlation between oocyte number and maturation rate as well as fertilization rate. However, a significant positive correlation was found between oocyte number and the blastulation rate. The implantation rate after fresh embryo transfers was higher in group 2 (6–15 oocytes) compared with group 1 (≤5 oocytes). According to our findings, we conclude that oocyte numbers between 6 and 15 oocytes can result in the highest chances of positive IVF outcomes in terms of embryo quality and fresh embryo transfers with lower risks of ovarian hyperstimulation.

Objective To compare the degree of efficiency between density gradient centrifugation (DGC) method and an extended horizontal swim-up (SU) method.Methods A total of 97 couples undergoing in vitro fertilization were enrolled in the study. Semen samples were divided into three aliquots and treated using DGC, extended horizontal SU, and combined methods. DNA fragmentation and chromatin decondensation were detected in native semen samples and their three corresponding aliquots. The corresponding mature oocytes of each semen sample were divided into two sibling cultures. The first sibling culture was microinjected with semen pellets from DGC, and the second sibling culture was microinjected with semen pellets from the combination of both methods. Fertilization rate and embryonic development were assessed at day 3.Results DNA fragmentation and chromatin decondensation was significantly low in DGC and extended horizontal SU samples; however, the rates of DNA fragmentation and chromatin decondensation were significantly lower in extended horizontal SU samples than in DGC samples. The lowest rates of DNA fragmentation and chromatin decondensation corresponded to the samples treated with both methods. The highest rates of DNA fragmentation and chromatin decondensation corresponded to the samples treated with DGC. No significant difference was found in the fertilization rate or day 3 embryos between sibling cultures.Conclusion The combination of DGC and the extended horizontal SU techniques is best for giving the lowest rates of sperm DNA fragmentation and chromatin decondensation.

Male infertility count for almost 30% of the total cases of infertility. Male infertility can be caused by several and various factors such as environmental, genetics and hormonal factors. Male infertility can be diagnosed through semen sample analysis; a fresh semen sample can indicate different semen abnormalities. A semen sample can indicate Azoospermia, Cryptozoospermia (Co) or Severe Oligozoospermia (ESO), who can cause infertility in male. It is challenging for an andrologist to distinguish between ESO and CO in clinic diagnose since both of them show no sperm in the sample in the initial sample test. In Cryptozoospermia or Severe Oligozoospermia, cryopreservation plays a significant part in preserving male fertility by freezing the individual sperm.

An abnormal uterus can sometimes be a risk factor for miscarriage and, in some cases, a cause of recurrent miscarriages. however, only some types of uterine malformations increase the risk of miscarriage and require treatment. others may not cause any problems with pregnancy at all. about 18% of women who have recurrent miscarriages have some type of uterine abnormality. Some uterine malformations are present from birth, while others develop during adulthood. most often, women with uterine abnormalities do not have any symptoms and are not aware of these malformations before they become pregnant. Diagnosis of congenital uterine malformations usually comes after a hysterosalpingogram (HSG), but this test can miss some conditions, such as uterine septum.Any abnormal HSG should be followed by a hysteroscopy. A uterine septum (septate uterus) is the most common congenital uterine anomaly, comprising roughly 55% of Mullerian duct anomalies. Congenital means that it is present at birth. A uterine septum is a band of fibrous tissue that partially or completely divides the uterus, usually without a good blood supply. If a fertilized egg implants on the septum, the placenta is unable to grow properly and miscarriage is likely, for women who have a septate uterus, the risk of miscarriage is significant. In fact, in one study nearly 67% of the women in the study with a septate uterus experienced pregnancy loss, for women who do not miscarry, a septate uterus may increase the risk of preterm birth. In fact, the same study found that the likelihood of having a full-term, normal-sized baby was only on 25%. treatment is usually minor surgery, performed during a hysteroscopy, to remove the abnormal tissue. this usually works extremely well to resolve the problem and allow women to successfully carry a full-term pregnancy.