Development Of Assisted Reproductive Technologies Research Articles

Prenatal post-implantation development of collared peccaries (Pecari tajacu Linnaeus, 1758).

Given the importance of information on intrauterine development in diagnosing anomalies in the gestational development of the species for the development of assisted reproduction technologies as well as understanding the autonomy and responsiveness of the newborn, the aim of the present study was to describe the external morphology of collared peccary conceptuses. For this study, two conceptuses were used per gestational age of 25-120 days post-copulation (dpc) and neonates with 145 dpc, totalling 22 animals. Females were euthanised, and embryos/foetuses were examined, measured, and photographed. During the first third of the gestational period (25-50 dpc, n = 8), a marked body curvature, brain vesicles, somites, internal organs, placid lens, auricular protrusion and limb buds are noted. In the second third of the gestational period (51-100 dpc, n = 10), foetuses lose their body curvature, displaying greater anatomical definition, including skeletal, external ears, nostrils, eyelids and tactile hair formation and cranial suture closure. In addition, dorsal scent gland and genital tubercle differentiation were visualized at 50 days post-copulation. In the third of the gestational period (101-145 dpc, n = 4), the organs become completely formed, alongside skin darkening, eyelid opening, dental eruption, dorsal odorous gland development, sexual organ externalization, and fanero attachment development. These data allowed for the construction of a prenatal growth curve, providing comparative anatomy information for ungulates and further contributing towards rational reproductive management and reproductive biotechnologies for this species.

Potential impact on using aspirin as the primary prevention of adverse pregnancy outcomes in twins conceived using ART

With the development of assisted reproductive technology, the number of twin pregnancies is increasing year by year. Given the increased risk of pregnancy complications associated with twin pregnancies, and the fact that these babies are rare and difficult to obtain through assisted reproductive technology, clinicians urgently require finding effective and safe drugs to improve pregnancy outcomes. Low-dose aspirin can not only promote placental blood supply, but also effectively anti-inflammatory. Whether Low-dose aspirin can effectively reduce the risk of pregnancy complications in this special group needs to be clarified. We therefore retrospectively analyzed 665 twin pregnancies from assisted reproduction technology, grouped according to aspirin use, and followed pregnancy outcomes to assess bleeding risk. Low-dose aspirin was found to be effective in preventing preeclampsia without a significant risk of bleeding. However, aspirin does not prevent specific complication in twin pregnancies and seems to have a better preventive effect only when the mother is under 30, which should alarm clinicians should not blindly using aspirin in this particular group.

The Role of Male Consent in Assisted Reproductive Technology Procedures: an Examination of Japanese Court Cases.

The online version contains supplementary material available at 10.1007/s41649-023-00274-1.

Definition of the Beginning of Life and Its Legal Significance

The article analyzes the positions of scientists, as well as the current legislation regarding the definition of the beginning of human life in the context of child conception and ensuring the right of human embryo for life. The problem has not only theoretical, but also important practical significance, as the grounds and limits of legal regulation of a number of relations depend on it. The definition of the beginning of life allows for optimal legal regulation, including the provision of legal guarantees to preserve the life of the human embryo. States independently decide on the establishment of prohibition on artificial termination of pregnancy or the time limits after which such a termination is prohibited. Attention is drawn to the development of assisted reproductive technologies, the emergence of the possibility to use cryopreserved embryos, which can be stored for a long time. There is a lack of development of this aspect in science and a small and heterogeneous judicial practice. According to the author, the use of cryopreserved embryos in resolving issues of inheritance of property, as well as after divorce, should be based on a contractual basis. Due to the fact that the legislation allows artificial termination of pregnancy up to a certain period, as well as on medical grounds, the best way to determine the legal capacity of the embryo (foetus) as conditional. Proposals are being made to improve the norms of civil law, including a proposal to call to inheritance for children born as a result of the use of the biomaterial of the testator for in vitro fertilization within six months after testator’s death and born alive after the opening of the inheritance.

Визначення особливостей перебігу вагітності та пологів, стану плода і новонародженого у вагітних після застосування допоміжних репродуктивних технологій (дані ретроспективного аналізу)

The rapid growth in the number of infertile couples leads to the development of assisted reproductive technologies (ART). Among the most common forms of infertility are tubo-peritoneal, endocrine, and caused by the male factor, and prevention of pregnancy complications caused by ART treatment cycles becomes one of the main tasks of practicing clinicians. Purpose - to determine the features of the course of pregnancy and childbirth; to assess the condition of the fetus and newborn in pregnant women after the application of ART to improve the perinatal outcomes of pregnancy and childbirth. Materials and methods. A retrospective clinical and statistical analysis of 334 histories of pregnancy and childbirth of women, as well as medical records of newborns from women, was conducted over the past five years, which formed the ART group - 221 history of pregnancy and childbirth, and the group of spontaneous pregnancy - 113 history of pregnancy and childbirth. Results. The structure of the subjects was statistically significant dominated by pregnant women over the age of 35 years and pregnant women in late reproductive age. The main characteristics of women after the ART application were a statistically significant predominance of somatic and gynecological pathology. The structure of pregnancy complications in women after ART application was dominated by threatening late spontaneous miscarriages, isthmic-cervical insufficiency and vaginitis, and in the structure of labor complications - anomalies of labor activity and premature rupture of fetal membranes. Among newborns from women in the ART group, perinatal mortality was 18.0%. Conclusions. The revealed features of somatic and gynecological anamnesis, as well as aspects of the course of pregnancy and childbirth and the condition of newborns in women after ART application are the basis for an in-depth examination of this category of pregnant women in order to improve approaches to predicting, diagnosing and optimizing preventive measures, as well as to improve the perinatal consequences of pregnancy and childbirth. The research was carried out in accordance with the principles of the Helsinki Declaration. The study protocol was approved by the Local Ethics Committee of the participating institution. No conflict of interests was declared by the authors.

Gamete Collection, Artificial Fertilization and Captive-Rearing of Eggs in a Terrestrial-Breeding Anuran with Parental Care: Alytes obstetricans.

The genus Alytes consists of six primitive terrestrial-breeding species (five of them endangered or present in restricted distributions) with unique male parental care. Alytes obstetricans was used as a model for the development of assisted reproductive technologies for gamete collection, artificial fertilization and captive-rearing of embryos. Sperm collection was achieved with human chorionic gonadotropin (hCG), but only 17 to 50% of males responded to the hormone. In addition, an effect of captivity on sperm quality was observed. A combination of gonadotropin-releasing hormone agonist (GnRHa) and hCG was tested for induction of ovulation, and 100% of females responded to the treatment. Recently collected sperm was used in artificial fertilization, and 10% of eggs showed complete embryo development. To design a method for captive-rearing of embryos, natural clutches (n = 13) were removed from males and divided into two sub-clutches. One was kept with all eggs together and in the other, the egg string was cut and eggs were split individually. All sub-clutches with eggs kept separated presented embryo survival (ranging from 27 to 61%) that hatched normally, while only one sub-clutch with embryos maintained together had some embryo survival (36%). These results may contribute to the management of this and related species.

An expanded view of infertility: The challenge of the changing profiling of major birth defects in China.

Over the past two decades, China has experienced a significant decline in birth rates, accompanied by a decrease in fertility and changes in major congenital defects. The development of assisted reproductive technology (ART) has brought hope to individuals facing infertility. However, some issues related to reproductive health and congenital defects have arisen. The reasons for the changing profiling of birth defects and the relationship between the decline in fertility and ART need to be further investigated. Lifestyle factors such as nutritional supplementation need to be altered to protect reproductive capacity. Birth defects, such as congenital heart defects and hypospadias, may serve as a signal for understanding the decline in fertility. To improve fertility, the factors contributing to it need to be identified, vital genetic and medical technologies need to be introduced, and environmental interventions, such as nutritional changes, need to be implemented.

Fact-finding survey on assisted reproductive technology in Japan.

In anticipation of the future development of assisted reproductive technology (ART) and to smoothly introduce new technology, it is necessary to understand the current staffing status of the medical system and the current state of treatment, as well as the status of in vitro fertilization add-ons, where the need for insurance coverage is currently a matter of debate. ART facilities in Japan were surveyed (437 valid responses, response rate: 71%). Current staffing status of the medical system, implementation rates of ART, add-on treatments, and medical supplies were investigated. Despite the abundance of embryologists, nurses, and obstetricians and gynecologists in facilities, the majority of facilities lacked counselors, anesthesiologists, and other essential medical professionals. Conventional ovarian stimulation was widely adopted (median 120 [interquartile range 60-300] cycles), followed by mild ovarian simulation (60 [30-200]). Additionally, freeze-thaw embryo transfer cycles (300 [120-750]) were performed more frequently than fresh embryo transfer cycles (30 [30-60]). Among the add-ons, assisted hatching (85.1%), chronic endometritis examination (77.2%) and treatment (76.9%), artificial oocyte activation (67.3%), endometrial receptivity analysis (64.2%), and endometrial microbiome analysis (58.9%) were relatively widely employed. The implementation of frozen-thawed embryo transfer cycles, freeze-all strategies, and add-on treatments have become popular and widely accepted despite the lack of robust evidence regarding their safety and efficacy.

Problems of subjects and legal personality in family law

In family legislation, unlike civil legislation, the subjects of legal relations are not directly named. In addition to the disparity of norms concerning subjects of family legal relations, the mobility of the composition of such persons, due to the evolution of society and law, is a problem. A comparative analysis of the norms of law and doctrinal positions is carried out, as a result of which various classifications of subjects of family legal relations are identified, the inclusion of organizations and public legal entities, the family as a quasi-legal entity, is justified. As a result of the introduction of the institution of the foster family, new special subjects of family legal relations appeared — foster children and foster parents. In connection with the development of assisted reproductive technologies, the issue of qualification of potential parents, sperm donor and surrogate mother as subjects of family legal relations has been raised. There is a problem of legal qualification of the embryo. The problems associated with the legal personality of participants in family legal relations are revealed: the mixing of marital and family legal personality, the absence of separate norms on family legal capacity and legal capacity, etc. It is proved that the scope of family legal personality varies depending on age, a number of other legal facts, including other sectoral nature; it is associated with the goal-setting of the exercise of rights and performance of duties.

SCM is potential resource for non-invasive preimplantation genetic testing based on human embryos single-cell sequencing

The ongoing development of assisted reproductive technologies has provided hope to individuals struggling with infertility, promising the potential for a healthy pregnancy. One significant innovation in field of pre-implantation genetic screening (PGS) requires the biopsy of embryos or oocytes, which has potential implications for the health and development of the resultant offspring. Therefore, a non-invasive approach to preimplantation genetic screening is highly sought after. The clinical application of non-invasive preimplantation genetic testing (ni-PGT) is currently limited, with its sensitivity and specificity requiring further investigation. In this study, we used 218 human embryos for single-cell whole genome amplification (WGA), along with ni-PGT of blastocoele fluid (BF) and spent culture medium (SCM). Whole blastocyst (WB), trophectoderm biopsy (TB), and inner cell mass (ICM) from embryo biopsies were used as controls to track genomic signal alterations. Our results showed that the overall genome similarity between SCM and ICM was higher than that of BF. Apart from the Y chromosome, both SCM and ICM demonstrated numerous variant sites across other chromosomes.Further categorization of gene variants in these two sample types revealed that missense variants were the most prevalent, single nucleotide polymorphisms were more common than insertions or deletions, and C > T was the dominant single nucleotide variants in both ICM and SCM. Lastly, we found that the mutant genes in SCM and ICM had different biological functions and pathways. This study indicates that SCM provides a more effective source of embryonic DNA for preimplantation genetic screening, offering a novel reference point for genetic screening research.

Recent Status of Pregnancies at an Advanced Maternal Age at a Japanese Perinatal Center.

Objective We compared the recent obstetric outcomes of women aged 40 and over as advanced maternal age (AMA) to those with AMA more than 10 years ago. Methods This was a retrospective study of primiparous singleton pregnancies who delivered at ≥22 weeks of gestation managed at Japanese Red Cross Katsushika Maternity Hospital between 2003-2007 and 2013-2017. Results The percentage of primiparous women aged with AMA who delivered at ≥22 weeks of gestation increased from 1.5 to 4.8% (p<0.01) due to the increase in the pregnancy conceived by in vitro fertilization (IVF). In the pregnancies with AMA, the percentage of cesarean delivery decreased from 51.7 to 41.0% (p=0.01), while the prevalence of postpartum hemorrhage increased from 7.5 to 14.9% (p=0.01). The latter was associated with an increased rate of in vitro fertilization (IVF) use. Conclusions The percentage of AMA pregnancies significantly increased with the development of assisted reproductive technology, and the prevalence of postpartum hemorrhage also increased in AMA pregnancies.

Estrogen upregulates DNA2 expression through the PI3K-AKT pathway in endometrial carcinoma.

Endometrial cancer is the most common gynecological malignancy, affecting up to 3% of women at some point during their lifetime (Morice et al., 2016; Li and Wang, 2021). Based on the pathogenesis and biological behavioral characteristics, endometrial cancer can be divided into estrogen-dependent (I) and non-estrogen-dependent (II) types (Ulrich, 2011). Type I accounts for approximately 80% of cases, of which the majority are endometrioid carcinomas, and the remaining are mucinous adenocarcinomas (Setiawan et al., 2013). It is generally recognized that long-term stimulation by high estrogen levels with the lack of progesterone antagonism is the most important risk factor; meanwhile, there is no definite conclusion on the specific pathogenesis. The incidence of endometrial cancer has been on the rise during the past two decades (Constantine et al., 2019; Gao et al., 2022; Luo et al., 2022). Moreover, the development of assisted reproductive technology and antiprogestin therapy following breast cancer surgery has elevated the risk of developing type I endometrial cancer to a certain extent (Vassard et al., 2019). Therefore, investigating the influence of estrogen in type I endometrial cancer may provide novel concepts for risk assessment and adjuvant therapy, and at the same time, provide a basis for research on new drugs to treat endometrial cancer.

Genomic insights into southern white rhinoceros (Ceratotherium simum simum) reproduction: Revealing granulosa cell gene expression

In vivo-collected granulosa cells (GC) from the southern white rhinoceros (SWR) provide a non-invasive assessment of the developmental status of oocytes prior to in vitro culture, which could aid in the development of assisted reproductive technologies (ART). Our study aimed to investigate gene expression in SWR granulosa cells, collected in vivo and gain preliminary insight into the transcriptional activity occurring within the cells during various stages of oocyte development. It was hypothesized there would be similarities between the SWR GC transcriptome and cattle and humans, two species for which well-annotated genomes are available and ART are commonly used. GC were collected from SWR following ovum pickup (OPU) and pooled from all aspirated follicles. Total RNA was isolated, libraries prepared, and sequencing performed using an Illumina NextSeq 500. Reads were aligned and annotated to CerSimCot1.0. Databases for cattle and human were acquired for comparison. This study identified 37,407 transcripts present in GC of SWR. It was determined that cattle and human transcriptomes are valuable resources with a homology of 45 % with the SWR. In conclusion, these data provide preliminary, novel insights into the transcriptional activity of GC in the SWR that can be used to enhance ART in this species.

Succinate dehydrogenase participation in porcine gamete function

Context Porcine gametes require energy for the physiological processes that allow fertilisation. Succinate dehydrogenase (SDH) plays a pivotal role in both, the tricarboxylic acid (TCA) cycle and the respiratory chain. Aims The aim of this work was to study the participation of SDH in the in vitro oocyte maturation, sperm capacitation and acrosome reaction in porcine species. Methods Cumulus–oocyte complexes (COCs) from abattoir-derived porcine ovaries were collected by aspiration and were incubated in maturation media, with the addition of increasing concentrations (0, 1, 5 and 10 mM) of malonate (a specific inhibitor of SDH). Nuclear maturation and cytoplasmatic maturation were analysed. Semen samples were incubated for 2 h in capacitating medium with 40 mM sodium bicarbonate, as sperm capacitation inducer, and the addition of increasing concentrations of malonate (0, 1, 5 and 10 mM). Sperm capacitation state and true acrosomal reaction were evaluated. SDH activity was determined in sperm and oocyte extracts by the spectrophotometric method. Key results The addition of 10 mM of malonate decreased both nuclear and cytoplasmic maturation rates (P &lt; 0.05) without affecting COC viability (assessed using fluorescein diacetate). A lower level of capacitation (induced by bicarbonate) and acrosome reaction (induced by follicular fluid) was observed with the addition of 5 mM of malonate (P &lt; 0.05) without affecting motility and viability of sperm at this concentration. The activity of SDH was 0.35 ± 0.1 × 10−5 and 2.37 ± 0.9 × 10−5 U/COC for immature and in vitro matured COC extracts (P &lt; 0.05) respectively, and 0.44 ± 0.16 U/1010 sperm for boar sperm extracts. Conclusions In conclusion, because it has been proposed that aerobic and anaerobic metabolic pathways of cells are changed depending on the oxygen availability and the composition of metabolic substrates in their environment, our results suggest that energy obtained through the mitochondrial respiration (TCA cycle and oxidative phosphorylation) is necessary to support oocyte maturation, sperm capacitation and acrosome reaction in the porcine species. Implications The study of enzymatic activity in gametes is essential for understanding the mechanisms that control the energy production required to achieve successful fertilisation. This knowledge has significant implications for the development of assisted reproductive technologies.

The Umbilical Cord and Complications of Twin Gestations

Abstract The rate of twin pregnancies has increased over the last decades, largely because of the ongoing development of assisted reproductive technology and increased maternal age at childbearing. Twins have a higher risk of adverse outcomes during pregnancy and the perinatal period. The prevalence of umbilical cord abnormalities is higher for twin pregnancies compared with singleton pregnancies. Some of these abnormalities are nonspecific to twinning and can also be found in singleton gestations (such as velamentous cord insertion, vasa previa, and single umbilical artery). Other abnormalities are associated with monochorionic twins, such as umbilical cord entanglement, and umbilical proximate cord insertion. Most of these abnormalities can be detected by ultrasound evaluation. The early and accurate ultrasound diagnosis of chorionicity, amnionicity, and placental and umbilical cord characteristics is crucial if we are to predict the risk of complications and to determine the best management for twin pregnancies. Histopathological examination of the placenta and umbilical cord after delivery can help to confirm prenatal diagnosis and to provide a better understanding of the physiopathology of their abnormalities. The aim of this review was to emphasize the role that the umbilical cord plays in twin complications and to describe the management of these high-risk pregnancies.

Gene mutations impede oocyte maturation, fertilization, and early embryonic development.

Reproductive diseases are a long-standing problem and have become more common in the world. Currently, 15% of the world's population suffers from infertility, and half of them are women. Maturation of oocytes, successful fertilization, and high-quality embryos are prerequisites for pregnancy. With the development of assisted reproductive technology and advanced genetic assays, we have found that infertility in many young female patients is caused by mutations in various developmental regulators. These pathogenic factors may result in impediment of oocyte maturation, failure of fertilization or early embryonic development arrest. In this review, we categorize these clinically-identified, mutated genetic factors by their molecular characteristics: nuclear factors (PALT2, TRIP13, WEE2, TBPL2, REC114, MEI1 and CDC20), cytoplasmic factors (TLE6, PADI6, NLRP2/5, FBXO43, MOS and BTG4), a factor unique to primates (TUBB8), cell membrane factor (PANX1), and zona pellucida factors (ZP1-3). We compared discrepancies observed in phenotypes between human and mouse models to provide clues for clinical diagnosis and treatment of related reproductive diseases.

Female sterilization reversal in the era of in-vitro fertilization.

Regret after female sterilization is not uncommon in the United States. Prior to the development of assisted reproductive technology (ART), surgical reversal of sterilization was the only option for patients interested in fertility. First performed in 1972, this procedure has since been refined over the years by gynaecologic surgeons. With in-vitro fertilization (IVF) gaining popularity, interest in sterilization reversal has waned. However, sterilization reversal should remain an important option in patients seeking pregnancy after tubal ligation. A direct comparison between IVF and sterilization reversal is challenging due to inherent differences in reporting fertility outcomes. However, sterilization reversal may optimize fertility in younger women, whereas IVF may be more effective in older women. The surgical approach to sterilization reversal can be laparotomic, laparoscopic or robotic. Clinical decision making should include consideration of the risk of ectopic pregnancy, interval from sterilization to reversal, type of sterilization procedure, planned anastomotic site and projected remaining tubal length. In the era of IVF, sterilization reversal still has a place in the management in restoring fertility. Creating awareness of the role of sterilization reversal is the first step in improving access to adequate training in this procedure for the next generation of reproductive surgeons.

Temporal trends and adverse perinatal outcomes of twin pregnancies at differing gestational ages: an observational study from China between 2012–2020

BackgroundWith the development of assisted reproductive technology, the twinning rate in China has been increasing. However, little is known about twinning from 2014 onwards. In addition, previous studies analysing optimal gestational times have rarely considered maternal health conditions. Therefore, whether maternal health conditions affect the optimal gestational time remains unclear.MethodsData of women delivered between January 2012 and December 2020 were collected through China’s National Maternal Near Miss Surveillance System. Interrupted time series analysis was used to determine the rates of twinning, stillbirth, smaller than gestational age (SGA), and low Apgar scores (< 4) among twins in China. To estimate the risk of each adverse perinatal outcome for separate gestational weeks, a multivariate generalised linear model was used. Infants born at 37 weeks of gestational age or foetuses staying in utero were used as reference separately. The analyses were adjusted for the sampling distribution of the population and the cluster effect at the hospital and individual levels were considered.ResultsThere were 442,268 infants enrolled in this study, and the adjusted rates for twinning, stillbirth, SGA, and low Apgar scores were 3.10%, 1.75%, 7.70%, and 0.79%, respectively. From 2012 to 2020, the twinning rate showed an increasing trend. Adverse perinatal outcomes, including stillbirth, SGA, and low Apgar scores showed a decreasing trend. A gestational age between 34 and 36 weeks decreased most for rate of stillbirth (average changing rate -9.72%, 95% confidence interval [CI] -11.41% to -8.00%); and a gestational age of between 37 and 38 weeks decreased most for rates of SGA (average changing rate -4.64%, 95% CI -5.42% to -3.85%) and low Apgar scores (average changing rate -17.61%, 95% CI -21.73% to -13.26%). No significant difference in changes in twinning rate or changes of each perinatal outcome was observed during periods of different fertility policies. Infants born at 37 weeks of gestation had a decreased risk of stillbirth, SGA, and low Apgar scores. Maternal antepartum or medical complications increased the risk of SGA and low Apgar scores in different gestational weeks.ConclusionChina’s twinning rate showed an increasing trend, while adverse perinatal outcomes decreased from 2012 to 2020. Fertility policy changes have had little effect on the twinning rate or the rate of adverse perinatal outcomes such as stillbirth, SGA, or low Apgar scores. The optimal gestational age for twins was 37 weeks. Women pregnant with twins and with antepartum or medical complications should be cautious due to an increased risk of SGA and low Apgar scores.

Correlation analysis of adverse outcomes for the selective reduction of twin pregnancies

BackgroundDue to the extensive development of assisted reproductive technology, the number of twin pregnancies has increased significantly over recent decades. Twin pregnancy is the most representative type of multiple pregnancies and is associated with high infant morbidity and mortality. Perinatal complications of twin pregnancy are also markedly increased compared with those of single pregnancy. Transabdominal selective reduction (SR) is a remedial intervention. This study aimed to research the adverse outcomes of transabdominal selective reduction of twin pregnancy and the correlation between the reduction week and pregnancy outcomes.ObjectiveThe purpose of this study was to examine the adverse outcomes of the transabdominal selective reduction of twin pregnancy and the correlation between the reduction week and pregnancy outcomes.MethodsA retrospective cohort study of the transabdominal reduction of twin pregnancy was conducted in a single prenatal diagnosis medical centre from September 2012 to October 2020. According to chorionicity, women with twin pregnancies were divided into 2 groups: dichorionic (DC) twin pregnancies and monochorionic (MC) twin pregnancies. Women with DC twin pregnancies underwent potassium chloride reduction, and those with MC twin pregnancies underwent radiofrequency ablation (RFA). The reduction indications included pregnancy complications, foetal abnormalities, and maternal factors. The perinatal outcomes of different chorionic twins after reduction were analysed. Each foetus with an adverse outcome was included. The relative relationship between the reduction weeks and delivery weeks of twins was examined by correlation analysis.ResultsA total of 161 women were included in this study. A total of 112 women had DC twin pregnancies, and 49 women had MC twin pregnancies. Preterm delivery rates were significantly higher in the MC twin reduction group than in the DC twin reduction group prior to 37 weeks (53.1% vs. 29.5%, P = 0.004). The mean gestational age at delivery of the foetuses in the DC twin group that underwent SR was significantly older than that of those in the MC twin group that underwent SR (36.9 ± 4.0 vs. 33.5 ± 6.6 weeks, P = 0.001). The number of DC twins that underwent SR and were delivered after 37 weeks was obviously greater than that of the MC twins that underwent SR (70.5% vs. 46.9%, P = 0.004). The foetal survival rate was 95.5% in the DC twin reduction group and 77.6% in the MC twin reduction group. If the indication of TTTS was not included, there was no significant difference in the foetal survival rate of the DC and MC twin reduction groups (95.5% vs. 86.2%, P = 0.160). Cotwin death 1 week after reduction was greater in the MC group (6.1% vs. 0%, P = 0.027). Compared to other indications, this finding indicated that a significantly lower proportion of women remained undelivered after selective reduction with the indication of TTTS. There was a significant negative correlation between the reduction weeks and delivery weeks of the two groups (P < 0.01), and the best opportunity for reduction was before 22 weeks of gestation.ConclusionThese findings highlighted an obviously negative correlation between the reduction week and delivery week. The transabdominal selective reduction of twin pregnancy should be considered for a lower rate of miscarriage or premature delivery if the reduction week takes place earlier in pregnancy. The rate of preterm delivery was the lowest when transabdominal selective reduction was completed before 22 weeks of gestation. Compared with other RFA indications, a higher rate of premature delivery was shown for MC twins with a reduction indication of TTTS. TTTS with sIUGR might be one of the reasons for the adverse outcomes of reduction for MC twin pregnancy.

Mammalian sperm capacitation: In vivo and in vitro juxtaposition

The development of assisted reproductive technologies (ART) in mammalian species such as in vitro embryo production (IVEP) has the potential to provide great benefits for significant population increase, improve genetic performance and advancement, and reduce transmission of venereal diseases. Correspondingly, in vitro capacitation of sperm is also paramount, related to the ability of sperm to fertilize oocytes, and was created to imitate in vivo conditions in the female reproductive tract. Amid in vitro capacitation developments, studies on how far in vitro capacitation has progressed in mimicking in vivo scenes have not been thoroughly reviewed as a comparative form. Therefore, the present study outlined the series of alterations in mammalian sperm capacitation during their journey in the female reproductive tract by exploring and juxtaposing processes under in vivo and in vitro conditions. Several essential aspects that become gaps between in vivo and in vitro were also identified and elaborated comprehensively in this systematic literature review. We noted that although in vitro capacitation procedures in certain mammalian species have made promising progress and improvements, it is still poorly successful in other species like horses. Our findings further postulated that the occurrence of cryocapacitation, the high ratio of capacitated sperm/oocyte required for successful fertilization, and the incidence of polyspermy cause capacitation under in vitro settings is less efficient and not yet fully comparable to in vivo. This work is therefore proposed several aspects that need to be bettered from in vitro milieu to make it analogous to in vivo environments in modulating sperm capacitation.