Medicina Reproductiva y Embriología Clínica最新文献

The role that long-acting reversible contraceptives, such as intrauterine devices (IUDs) can play in reducing the rate of unwanted pregnancies makes overcoming barriers to their use gain in importance. This paper reviews some of the most common barriers to the wide use of IUDs –including levonorgestrel-releasing intrauterine systems (LNG-IUSs)-, offering useful information and suggestions on key aspects before, during and after placement of these devices. To this end, the most up-to-date scientific evidence has been reviewed and where evidence is insufficient, the authors draw on their experience. Among the aspects to be considered before IUD placement, we examine how to determine a woman's eligibility, how to provide proper information, the need to know which IUD is best suited to her characteristics and needs and when is the best time for placement. Studies on pharmacological and non-pharmacological interventions that have been shown to have an effect on pain relief during IUD placement are discussed. Factors that can predict pain are also discussed, as well as how to help minimize it by improving women's experience during insertion. The risk for complications such as uterine perforation is low. Despite this, healthcare practitioners should be trained on how to manage them and should properly inform users on warning signs and symptoms. IUD placement can be especially difficult in women who present with stenosis after conization or who have undergone a Caesarean section, which we also analyze. Lastly, we examine management of vasovagal syncope and post-placement side-effects, such as pain or lost threads and provide guidelines for follow-up visits.

Selecting the best embryos to transfer is essential in any in vitro fertilization treatment. For years, embryo morphology supported this selection. Now, the field is seeking more accurate and non-invasive methods for selection. Recent studies show that embryos that do not result in successful pregnancy exhibit different metabolomic profiles from those embryos that result in successful pregnancy, opening a new possibility in the field. Metabolomic profiling and analysis of the cell-free DNA released by the embryo to the culture media are the most promising techniques for embryo selection developed so far.

Pluripotent stem cells and spermatogonial stem cells are stem cell types specialized for reconstitution of germ cell development in vitro, as they are capable of differentiating into gametes. Reconstitution of germ cell development, termed in vitro gametogenesis, will provide an experimental platform for a better understanding of germ cell development, as well as an alternative source of artificial gametes for reproduction, with the potential to treat and cure infertility. Since germ cells are especialized cells that will pass all genetic information into the next generation, both the in vitro culture system and its derived-cells from stem cells must be carefully evaluated. In this review, we summarize the progress in in vitro gametogenesis, most of which has been made using mouse models, as well as the future challenges in this field.

Diet and exposure to certain chemical compounds related to industrial development could be responsible for the increase in the incidence of human reproductive diseases and the consequent decrease in reproductive function worldwide. The role of diet and environment in fertility has received more attention in recent years because nutrition and exposure to contaminants can affect fecundity in women of reproductive age. Here, we review how diet could affect reproduction. Furthermore, we will review how the most ubiquitous contaminants could disrupt endometrial receptivity and implantation, focusing also on clinical studies performed in the last years.

Preimplantation genetic testing is implemented worldwide as an effective tool to avoid transmission of single gene disorders and/or chromosome abnormalities. This approach requires the obtention of representative samples from embryos in order to infer its genetic status. Nowadays, the embryo biopsy is the first-choice method for embryo sampling. Biopsy procedures are safe and widely performed in the clinical routine. However, this intervention is invasive and requires trained personnel and investment in specific equipment. Recently, new sampling methods have been suggested under the term of “non-invasive”. These approaches are based on the existence of cell-free DNA into the embryo or its environment. An increasing number of studies suggest the collection of fluid from embryos or spent culture medium to obtain cell-free DNA to assess the genetic condition of preimplantation embryos avoiding embryo biopsy. The reliability of this attractive idea needs to be confirmed and validated. In this sense, this work offers a deep review of data published to date. Several methods of DNA detection, quantification and amplification have been tested and different protocols and culture systems, with or without additional embryo manipulations, are being investigated. In general terms, an enormous variability among published results is noteworthy. Central aspects as DNA detection rates, contamination with extraembryonic DNA and concordance between results (cell-free DNA versus embryo samples) are centring proofs-of-concept and validation experiments. However, basic questions as the biological origin and representativeness of cell-free DNA are pending to be answered. Solved, unsolved and serious limitations of the new approaches are discussed. A final reflection respecting the state of the technique is offered.

Introduction

The aim of this work, is to find the prevalence of marijuana use in a subfertile population, and to carry out a comparative prospective study of the seminogram parameters of a group of subfertile patients, who are habitual marijuana users, versus a group of nested control cases of non-users.

Material and methods

2320 men were studied, 70% of patients from Primary Care Centers and 30% from hospital outpatient consultations. The analysis of sperm concentration and motility was carried out with a SCA® automated semen analyzer. The comparative study has been carried out, by applying a novel statistical methodology called «case-control nested», which is a hybrid case-control variation.

Results

The prevalence of marijuana use has been calculated in a population of subfertile men. Statistical analysis of the semen values of the group of marijuana users versus the control group shows that there are no significant differences between them.

Conclusions

In the group of subfertile men studied, a prevalence of 10.26% of habitual marijuana users was observed. In our results, no significant differences were observed between the two groups studied, so we are considering the additional performance of new sperm functionalism tests, to explain the subfertility that has been observed in some of these patients who use marijuana, who present a normal seminogram.