Factors influencing natural fecundity in fertile couples: a survey of puerperae and their partners.

RESEARCH QUESTION: What is the fecundity rate among fertile couples, and which factors influence it? DESIGN: Retrospective study of all puerperae attending Cruces University Hospital Human Reproduction Unit over 9 months. An anonymous questionnaire was circulated to all patients, and 2510 valid completed questionnaires were collected. The main inclusion criterion was natural conception resulting in delivery. Pregnancies resulting from ART and contraceptive method failure were excluded. Investigated parameters were time to pregnancy, age and smoking (in women and men), previous pregnancies and intercourse frequency. A mathematical formula was developed to predict the per-month fecundity rate (PMFR). RESULTS: The cumulative fecundity rate was 29.08%, 54.26%, 68.61%, 89.88%, 96.95% and 98.63% (at 1, 3, 6, 12, 24 and 36 months); between 12 and 36 months, the average PMFR ranged from 8.53-7.48%. Only 1.68% of pregnancies occurred between 24 and 36 months, and only 1.37% thereafter. The best fecundity markers were obtained in the group who had sexual intercourse seven to eight times a week. Women and men younger than 25 years had lower fecundity markers than those aged between 25 and 40 years. CONCLUSIONS: Fertile couples have a non-negligible per-month fecundity rate between 12 and 36 months, which should be considered when planning fertility studies. The lower fecundity rate observed in women and men aged younger than 25 years deserves more study. Coital frequencies of more than two or three times a week did not affect the fecundity rate and was better with frequencies of seven to eight times a week.

Safety of Plasma Rich in Growth Factors (PRGF) as additive to healthy human sperm samples: a pilot study.

OBJECTIVE: The aim of our study was to assess if the addition of PRGF to healthy human sperm affects its motility and vitality. METHODS: This was a prospective study, with 44 sperm donors on whom sperm analysis was performed. Nine mL of blood was collected and PRGF was obtained using PRGF-Endoret® technology. The influence of different dilutions of PRGF (5%, 10%, 20%, 40%) applied to 15 sperm donors was compared, and sperm motility was assessed after 30 minutes. In the second part of the study, 29 sperm donors were studied to analyze the influence of 20% dilution of PRGF at 15, 30 and 45 minutes in fresh and thawed sperm samples. Motility was assessed after the addition of PRGF and after analysis each aliquot was frozen. After thawing, concentration and motility were assessed at the same time periods. RESULTS: There were no differences in sperm motility in fresh samples between dilutions of PRGF when assessed 30 minutes after administration, nor between them, nor when compared to the control group immediately prior to treatment. No trend was observed between motility and PRGF dilution in linear regression analysis. There were no significant differences in thawed samples. CONCLUSIONS: The administration of 20% PRGF dilution had no effect on sperm motility compared to samples without PRGF. In addition, there was no change in sperm vitality when comparing samples with and without PRGF. More studies focusing on subnormal sperm samples, analyzing different PRGF concentrations and increasing the number of study variables are needed.

Early Spontaneous Twinning Recorded By Time-Lapse.

Monozygotic twins (MZT) are 2.5 times more frequent in ART than in natural conceptions. A number of ART-related mechanisms have been probably linked with MZT. Studies that retrospectively analyze the time-lapse (TL) records resulting in MZT suggest that some morphokinetic traits of the inner cell mass and the trophectoderm could be predictors of MZT, but results are controversial. We present the complete TL record of one case of MZT that split itself at the very moment of the division into two cells, with one of the cells coming out through a hole in the zona pellucida (ZP). Both resulting embryos developed normally, and were vitrified. It is suggested that the hole in the ZP may facilitate the extrusion of some cells of the

Cell-cell interactions during the formation of primordial follicles in humans.

Gametogenesis is a complex and sex-specific multistep process during which the gonadal somatic niche plays an essential regulatory role. One of the most crucial steps during human female gametogenesis is the formation of primordial follicles, the functional unit of the ovary that constitutes the pool of follicles available at birth during the entire reproductive life. However, the relation between human fetal germ cells (hFGCs) and gonadal somatic cells during the formation of the primordial follicles remains largely unexplored. We have discovered that hFGCs can form multinucleated syncytia, some connected via interconnecting intercellular bridges, and that not all nuclei in hFGC-syncytia were synchronous regarding meiotic stage. As hFGCs progressed in development, pre-granulosa cells formed protrusions that seemed to progressively constrict individual hFGCs, perhaps contributing to separate them from the multinucleated syncytia. Our findings highlighted the cell-cell interaction and molecular dynamics between hFGCs and (pre)granulosa cells during the formation of primordial follicles in humans. Knowledge on how the pool of primordial follicle is formed is important to understand human infertility.

Natural killer cell subsets in endometrial fluid: a pilot study of their association with the endometrial cycle and reproductive parameters.

PURPOSE: To investigate if there are natural killer (NK) cells in endometrial fluid (EF) and their relationship with the endometrial cycle and reproductive parameters. METHODS: The population under study consisted of 43 women aged 18-40 undergoing infertility workup at our University Hospital in 2021-2022. The EF samples were obtained at the first visit to our unit, on occasion of the mock embryo transfer. The day of the cycle was considered only in cycles of 27-29 days. An immunophenotype study of NK in EF was performed by flow cytometry analysis. In a subgroup of women, on the same day, NK was studied in EF and peripheral blood. RESULTS: Our study is the first to evidence NK cells in EF. None of the NK cells observed corresponded to a mature peripheral blood NK cell population (stages 4-5), and neither endometrial nor decidual uNK cells were detected. Nevertheless, we found 2 patient groups with an NK cell subset with a higher expression of CD16+, which could belong to an intermediate or transient stage between the uNK and pbNK NK cell population in the EF. We found that CD16 was significantly increased in the mid-late luteal phase and its correlation with the day of the cycle. The NK immunophenotype was different in EF and peripheral blood. CONCLUSION: We described a new component of the EF, the NK cells, whose CD16 activity is closely correlated with the day of the cycle. These cells could play a role in implantation/implantation failure.

Delta and kappa opioid receptors in human endometrium during the menstrual cycle: Expression and localization.

OBJECTIVE: Endogenous opioid peptides were reported to be involved in the regulation of reproductive physiology and their precursors and receptors were described in many of the male and female reproductive tissues. Mu opioid receptor (MOR) was described in human endometrial cells and its expression and localization changed during the menstrual cycle. However, there is no data from the distribution of the other opioid receptors: Delta (DOR) and Kappa (KOR). The objective of the present work was to analyze the dynamics of expression and localization of DOR and KOR in human endometrium throughout the menstrual cycle. STUDY DESIGN: Human endometrial samples from different menstrual cycle phases were analyzed by immunohistochemistry. RESULTS: DOR and KOR were present in all samples analyzed and the protein expression and localization changed throughout the menstrual cycle. Both receptor expression increased during the late proliferative phase and decreased during the late secretory-one, especially in the luminal epithelium. DOR expression was generally higher than KOR expression in all cell compartments. CONCLUSIONS: The presence of DOR and KOR in human endometrium and their dynamic changes during the menstrual cycle join the results previously obtained in MOR suggesting a possible role of opioids in reproduction events related to the human endometrium.

Endometriosis Increases the Risk of Placenta Previa in Both IVF Pregnancies and the General Obstetric Population.

Is there a relationship between endometriosis and placenta previa (PP)? To investigate if there is a relationship between endometriosis and PP, a retrospective study was carried out, using prospectively recorded data from two different databases from Cruces University Hospital. Two different populations were included in the study. The ART (assisted reproduction techniques) population consisted of 246 cesarean sections (CS), from a total of 1170 deliveries, and the obstetric population consisted of 7045 CS, from a total of 50,298 deliveries. A representative subset from the obstetric population was established selecting 4 CS without PP for each CS with PP. In our ART population, the PP rate was 1.71% among all deliveries and 8.13% among CS. In our general obstetric population, the PP rate was 0.34% among all deliveries and 2.41% among the CS. Among the CS in ART pregnancies, the PP rate was 20% in the women with endometriosis vs 5.47% in women without endometriosis (OR = 4.32; 95% CI = 1.67-11.17), while considering all ART deliveries, the PP rates were 6.43% and 1.07%, respectively (OR = 6.36; 95% CI = 2.59-15.65). In the CS-obstetric population, the rate of PP was 9.61% among women with endometriosis vs 2.19% among women without endometriosis (OR = 4.74; 95% CI = 2.91-7.73). Considering all deliveries, the PP rate was 1.35% among women with endometriosis vs 0.30% in women without endometriosis. Differences persisted when adjusting for age, IVF, multiplicity, and previous deliveries. In the CS-obstetric population with PP, mean surgical time and hospital stay were significantly higher in women with endometriosis. Endometriosis is associated with a higher risk of PP even after adjusting for other parameters.

Polycystic ovarian syndrome and miscarriage in IVF: systematic revision of the literature and meta-analysis.

PURPOSE: To evaluate the risk of miscarriage in IVF cycles in women with PCOS. METHODS: Systematic review and meta-analysis. Systematic search of MEDLINE, EMBASE and Google Scholar. The language search was restricted to English, Spanish and French, from 2000 to 2019, with crosschecking of references from relevant articles. Inclusion criteria were: (1) IVF cycles (2) a group of patients with PCOS was considered separately, (3) the miscarriage rate was reported, (4) there was a control group, (5) definition of PCOS according the Rotterdam criteria. Exclusion criteria were been excluded from the meta-analysis: (1) publication prior to the year 2000, (2) animal studies, (3) reviews, (4) abstracts or conference papers, (5) letters, (6) case reports, (7) studies comparing different IVF techniques, (8) studies comparing groups with and without metformin or other treatments, (9) studies on induced abortions. Risk of bias was assessed by the Newcastle-Ottawa score (NOS). All the included studies had a low risk of bias (NOS scores ranging 7-8). The review protocol was registered in PROSPERO (CRD42020186713). Seventeen studies were included in the meta-analysis. There was a total of 10,472 pregnancies (2650 in PCOS and 7822 in controls) of which 1885 were miscarriages (682 in PCOS and 1203 in controls). We considered the miscarriage rate (MR), preclinical MR, early MR, and late MR. RESULTS: In IVF pregnancies the risk of miscarriage was significantly increased when considering miscarriages in total (RR = 1.59; CI = 1.45-1.75), preclinical miscarriages (RR = 1.59; CI = 1.35-1.88), and early miscarriages (RR = 1.44; CI = 1.16-1.79). The increased miscarriage rate persisted in Chinese and Western populations when considered separately. The risk of miscarriage was increased in the subgroup of fresh transfers (RR = 1.21; CI = 1.06-1.39) as well as in the subgroup including either fresh or frozen transfers (RR = 1.95; CI = 1.72-2.22). CONCLUSION: PCOS is linked to an increased MR in IVF pregnancies both of miscarriages in total, and to an increase in preclinical and early miscarriages. PROSPERO NUMBER: CRD42020186713.

Comparison of the Administration of 150 or 75 IU of Recombinant LH in Agonist ICSI Cycles Stimulated with Recombinant FSH in Women Aged 35-39: A Comparative Study.

Background: The purpose of the study was to assess whether the coadministration of 150 IU of recombinant LH instead of 75 IU in women aged 35-39 improves the results in agonist ICSI cycles stimulated with 300 IU of recombinant FSH. Methods: In this study, two ovarian stimulation protocols coexisted which were identical except in the administered dose of recombinant LH, for which some patients received 150 IU (n=231) and some received 75 IU (n=216). Both groups received 300 IU of recombinant FSH. Gonadotropins were reimbursed by the National Health System. Statistical analysis was performed by Student's t test, χ2, and ANCOVA. Significance level was established at p=0.05. Results: The number of retrieved oocytes was slightly higher in the 300/150 group (9.06±5.53 vs. 8.61±5.11), but the differences were not significant. Results were similar with the number of metaphase II oocytes (7.18±4.86 vs. 6.72±4.72) and the number of fertilized oocytes (4.64±3.2 vs. 4.23±2.72). The per-transfer clinical pregnancy rates exhibited close similarity between both groups (32.84% vs. 32.46%), as did the per-transfer live birth rates (29.90% vs. 30.37%) and the implantation rate. The rate of hyperstimulation syndrome (OHSS) as well as the rate of cancellation due to OHHS risk was similar in both groups. There was also no difference in the miscarriage rate. When results were expressed by per started cycle or by oocyte pick-up, the results remained very similar in both groups. Conclusion: In women aged 35-39 undergoing ovarian stimulation with recombinant FSH in agonist cycles, the coadministration of 75 or 150 UI of recombinant LH did not influence pregnancy rates. However, a slight increase in the number of retrieved oocytes should not be disregarded.

microRNA-based signatures obtained from endometrial fluid identify implantative endometrium.

STUDY QUESTION: Is it possible to use free and extracellular vesicle-associated microRNAs (miRNAs) from human endometrial fluid (EF) samples as non-invasive biomarkers for implantative endometrium? SUMMARY ANSWER: The free and extracellular vesicle-associated miRNAs can be used to detect implantative endometrium in a non-invasive manner. WHAT IS KNOWN ALREADY: miRNAs and extracellular vesicles (EVs) from EF have been described as mediators of the embryo-endometrium crosstalk. Therefore, the analysis of miRNA from this fluid could become a non-invasive technique for recognizing implantative endometrium. This analysis could potentially help improve the implantation rates in ART. STUDY DESIGN, SIZE, DURATION: In this prospective study, we first optimized different protocols for EVs and miRNA analyses using the EF of a setup cohort (n = 72). Then, we examined differentially expressed miRNAs in the EF of women with successful embryo implantation (discovery cohort n = 15/validation cohort n = 30) in comparison with those for whom the implantation had failed (discovery cohort n = 15/validation cohort n = 30). Successful embryo implantation was considered when pregnancy was confirmed by vaginal ultrasound showing a gestational sac 4 weeks after embryo transfer (ET). PARTICIPANTS/MATERIALS, SETTING, METHODS: The EF of the setup cohort was obtained before starting fertility treatment during the natural cycle, 16-21 days after the beginning of menstruation. For the discovery and validation cohorts, the EF was collected from women undergoing frozen ET on Day 5, and the samples were collected immediately before ET. In this study, we compared five different methods; two of them based on direct extraction of RNA and the other three with an EV enrichment step before the RNA extraction. Small RNA sequencing was performed to determine the most efficient method and find a predictive model differentiating between implantative and non-implantative endometrium. The models were confirmed using quantitative PCR in two sets of samples (discovery and validation cohorts) with different implantation outcomes. MAIN RESULTS AND THE ROLE OF CHANCE: The protocols using EV enrichment detected more miRNAs than the methods based on direct RNA extraction. The two most efficient protocols (using polymer-based precipitation (PBP): PBP-M and PBP-N) were used to obtain two predictive models (based on three miRNAs) allowing us to distinguish between an implantative and non-implantative endometrium. The first Model 1 (PBP-M) (discovery: AUC = 0.93; P-value = 0.003; validation: AUC = 0.69; P-value = 0.019) used hsa-miR-200b-3p, hsa-miR-24-3p and hsa-miR-148b-3p. Model 2 (PBP-N) (discovery: AUC = 0.92; P-value = 0.0002; validation: AUC = 0.78; P-value = 0.0002) used hsa-miR-200b-3p, hsa-miR-24-3p and hsa-miR-99b-5p. Functional analysis of these miRNAs showed strong association with key implantation processes such as in utero embryonic development or transforming growth factor-beta signaling. LARGE SCALE DATA: The FASTQ data are available in the GEO database (access number GSE178917). LIMITATIONS, REASONS FOR CAUTION: One important factor to consider is the inherent variability among the women involved in the trial and among the transferred embryos. The embryos were pre-selected based on morphology, but neither genetic nor molecular studies were conducted, which would have improved the accuracy of our tests. In addition, a limitation in miRNA library construction is the low amount of input RNA. WIDER IMPLICATIONS OF THE FINDINGS: We describe new non-invasive protocols to analyze miRNAs from small volumes of EF. These protocols could be implemented in clinical practice to assess the status of the endometrium before attempting ET. Such evaluation could help to avoid the loss of embryos transferred to a non-implantative endometrium. STUDY FUNDING/COMPETING INTEREST(S): J.I.-P. was supported by a predoctoral grant from the Basque Government (PRE_2017_0204). This study was partially funded by the Grant for Fertility Innovation (GFI, 2011) from Merck (Darmstadt, Germany). It was also supported by the Spanish Ministry of Economy and Competitiveness MINECO within the National Plan RTI2018-094969-B-I00, the European Union's Horizon 2020 research and innovation program (860303), the Severo Ochoa Centre of Excellence Innovative Research Grant (SEV-2016-0644) and the Instituto de Salud Carlos III (PI20/01131). The funding entities did not play any role in the study design, collection, analysis and interpretation of data, writing of the report or the decision to submit the article for publication. The authors declare no competing interests.

Aspiration of excess follicles before intrauterine insemination in high response cycles.

Purpose: To assess the outcome of excess follicle aspiration before intrauterine insemination (EFABI) in intrauterine insemination (IUI) cycles with 4-6 follicles ≥14 mm. Methods: A retrospective case-control study with 1559 patients undergoing IUI (donor and husband's sperm), of whom 86 underwent EFABI. We studied also an historical series of 2213 patients before EFABI implementation. For 3.5 years, all women undergoing IUI developing 4-6 follicles ≥14 mm were offered EFABI on the day of hCG administration. Pregnancy rates (PRs), multiple PRs, and adverse effects were measured. Results: EFABI was associated with a similar multiple PR (17.8% vs 17.5% in non-EFABI cases), with no triplets in EFABI patients. Live birth rates were significantly higher in EFABI cycles in IUI overall (25.5% vs 15.2%). When considered separately, the performance of EFABI resulted in significantly increased live birth rates in IUI-donor cycles (32.5% vs 18.5%), whereas the differences in IUI-husband cycles (19.5% vs 12.9%) did not reach statistical significance. The PR was 21.2% during the EFABI implementation period and 19.4% in the pre-EFABI period. Conclusions: EFABI in cycles in which 4-6 follicles reach ≥14 mm is a simple option that reduces cycle cancellation rates, results in higher PRs than cycles with 1-3 follicles, and lowers the risk of multiple pregnancy.

Physical activity and sperm quality: influence in sperm donors.

PURPOSE: To ascertain whether physical activity (PA) is associated with better sperm quality in sperm donors. METHODS: A prospective case-control study was designed in an IVF center setting. A total of 207 sperm donation candidates from a relatively small geographical area were included in the study with no intervention. Donor candidates were subjected to conventional sperm analysis according to WHO criteria. Moreover, they answered a standardized questionnaire regarding their last week PA (IPAQ), with PA expressed in metabolic equivalents (METs)-min/week. Donors were classified into 4 groups: low, moderate, high and very high PA. Specific sports were included in the questionnaire. Semen samples from 43 accepted donors were used in artificial insemination by donor (AID) and IVF. The fertilization rates (FR) and pregnancy rates (PR) were studied. RESULTS: Semen volume, sperm concentration, progressive spermatozoa, non-progressive spermatozoa, total motile progressive spermatozoa and sperm morphology were similar in the four PA groups. No correlation between various semen parameters studied and METs was found. Running or cycling > 1 h/week did not influence sperm parameters. The AID PR was similar in the different PA groups. However, in IVF the mean donor FR was significantly higher in the high PA group and in the very high PA group. CONCLUSIONS: No detrimental effect was associated with PA, or even very high PA, regarding conventional sperm parameters. Moreover, a better FR was associated with high and very high PA in IVF cycles, which merits more studies.

Originator recombinant human follitropin alfa versus recombinant human follitropin alfa biosimilars in Spain: A cost-effectiveness analysis of assisted reproductive technology related to fresh embryo transfers.

This study compared the cost per live birth and cost-effectiveness of the originator recombinant human follicle-stimulating hormone follitropin alfa (r-hFSH-alfa) and r-hFSH-alfa biosimilars for ovarian stimulation prior to assisted reproductive technology treatment in Spain. A decision tree model was developed, comprising pregnancy and live birth for one treatment cycle with fresh embryo transfer. Clinical inputs were based on a recent meta-analysis by Chua et al. [4]. Cost inputs were extracted from publicly available Spanish sources. The costs per live birth were lower with originator r-hFSH-alfa (€18,138) versus r-hFSH-alfa biosimilars (€20,377). The incremental cost-effectiveness ratio was €7208 for originator r-hFSH-alfa versus biosimilars. Drug acquisition costs for originator r-hFSH-alfa represented 10.5% of total costs in the base case analysis, and 6.2% in a treatment cycle resulting in live birth with one fresh embryo transfer. Results from the sensitivity analyses confirmed the robustness of the findings.

Women's vitamin D levels and IVF results: a systematic review of the literature and meta-analysis, considering three categories of vitamin status (replete, insufficient and deficient).

To investigate the influence of vitamin D status on in vitro fertilisation (IVF) results, a meta-analysis of 15 cohort studies of 3711 women undergoing IVF was performed. Women were classified into three groups according their vitamin D levels (≥30 ng/mL considered replete/sufficient; 21-29 ng/mL insufficient and <20 ng/mL deficient). Three different meta-analyses were performed: (i) sufficient vs deficient; (ii) sufficient vs 'insufficient + deficient'; (iii) 'sufficient + insufficient' vs deficient. Comparing IVF outcomes in sufficient versus deficient groups (considering autologous and donor oocyte cycles together), we found women with sufficient vitamin D had significantly higher biochemical pregnancy (OR = 1.43 [1.06-1.95]), ongoing pregnancy (OR = 1.29 [1.02-1.64]), and live birth (OR = 1.74 [1.31-2.31]) rates, with a non-significant trend to a higher clinical pregnancy rate (OR = 1.31 [0.94-1.82]), whereas implantation and miscarriage rates were similar. When the meta-analysis was restricted to autologous oocytes, the parameters which had been significant in the joint analysis remained significant, and differences in implantation (OR = 1.64, [1.17-2.29]) and clinical pregnancy (OR = 1.47 [1.2-1.69]) rates became significant. No significant differences were found when considering only cycles with donor oocytes. The sufficient + insufficient vs deficient and sufficient vs 'insufficient + deficient' comparisons identified significant differences in live birth rate. The meta-analysis shows that sufficient vitamin D status is associated with better outcomes in IVF. Nonetheless, there are many demographic, geographic and clinical parameters that may be related to vitamin D status that need to be ascertained before concluding that the better results are due to the higher levels of vitamin D.

Transcriptional progression during meiotic prophase I reveals sex-specific features and X chromosome dynamics in human fetal female germline.

During gametogenesis in mammals, meiosis ensures the production of haploid gametes. The timing and length of meiosis to produce female and male gametes differ considerably. In contrast to males, meiotic prophase I in females initiates during development. Hence, the knowledge regarding progression through meiotic prophase I is mainly focused on human male spermatogenesis and female oocyte maturation during adulthood. Therefore, it remains unclear how the different stages of meiotic prophase I between human oogenesis and spermatogenesis compare. Analysis of single-cell transcriptomics data from human fetal germ cells (FGC) allowed us to identify the molecular signatures of female meiotic prophase I stages leptotene, zygotene, pachytene and diplotene. We have compared those between male and female germ cells in similar stages of meiotic prophase I and revealed conserved and specific features between sexes. We identified not only key players involved in the process of meiosis, but also highlighted the molecular components that could be responsible for changes in cellular morphology that occur during this developmental period, when the female FGC acquire their typical (sex-specific) oocyte shape as well as sex-differences in the regulation of DNA methylation. Analysis of X-linked expression between sexes during meiotic prophase I suggested a transient X-linked enrichment during female pachytene, that contrasts with the meiotic sex chromosome inactivation in males. Our study of the events that take place during meiotic prophase I provide a better understanding not only of female meiosis during development, but also highlights biomarkers that can be used to study infertility and offers insights in germline sex dimorphism in humans.

Antibacterial and Antifungal Activity of the Human Endometrial Fluid during the Natural Cycle.

Purpose: Some microbiota patterns have been associated with favorable IVF prognosis and others with pathological conditions. The endometrial fluid aspirate (EFA) contains antibacterial proteins that are enriched in implantative IVF cycles, but the antimicrobial effect of EFA has not been addressed. We aimed to evaluate the antimicrobial activity of the human endometrial fluid during the natural cycle. Methods: EFA was obtained through an embryo transfer catheter in 38 women, aged 18-40 years, with regular cycles attending to a fertility clinic. The antimicrobial activity of EFAs was tested against two strains of Staphylococcus aureus; one strain each of Streptococcus agalactiae, Enterococcus faecalis, Escherichia coli, and Klebsiella pneumoniae; and three yeasts (Candida albicans, Candida glabrata, and Candida krusei). Results: All samples exhibited antibacterial activity against S. aureus. In addition, 32.4% of EFAs were active against one of the other microorganisms assayed, 16.2% against two, and 5.4% against four of them. In contrast, none exhibited antibacterial activity against E. coli or K. pneumoniae. The antimicrobial activity differs considerably between EFA samples, and we failed to observe a cycle-related pattern. Conclusions: EFA presented two antimicrobial activity patterns: (a) one common to all the samples, exhibiting activity against S. aureus and lack of activity against E. coli and K. pneumoniae, and (b) an individualized pattern, showing activity against some of the other microorganisms tested. The intensity of antibacterial activity differs between EFA samples. Our data suggest that the uterine microbiota is controlled by means of endometrial fluid components.

Proteomics based drug repositioning applied to improve in vitro fertilization implantation: an artificial intelligence model.

Embryo implantation is one of the most inefficient steps in assisted reproduction, so the identifying drugs with a potential clinical application to improve it has a strong interest. This work applies artificial intelligence and systems biology-based mathematical modeling strategies to unveil potential treatments by computationally analyzing and integrating available molecular and clinical data from patients. The mathematical models of embryo implantation computationally generated here simulate the molecular networks underneath this biological process. Once generated, these models were analyzed in order to identify potential repositioned drugs (drugs already used for other indications) able to improve embryo implantation by modulating the molecular pathways involved. Interestingly, the repositioning analysis has identified drugs considering two endpoints: (1) drugs able to modulate the activity of proteins whose role in embryo implantation is already bibliographically acknowledged, and (2) drugs that modulate key proteins in embryo implantation previously predicted through a mechanistic analysis of the mathematical models. This second approach increases the scope open for examination and potential novelty of the repositioning strategy. As a result, a list of 23 drug candidates to improve embryo implantation after IVF was identified by the mathematical models. This list includes many of the compounds already tested for this purpose, which reinforces the predictive capacity of our approach, together with novel repositioned candidates (e.g., Infliximab, Polaprezinc, and Amrinone). In conclusion, the present study exploits existing molecular and clinical information to offer new hypotheses regarding molecular mechanisms in embryo implantation and therapeutic candidates to improve it. This information will be very useful to guide future research.Abbreviations: IVF: in vitro fertilization; EI: Embryo implantation; TPMS: Therapeutic Performance Mapping System; MM: mathematical models; ANN: Artificial Neuronal Networks; TNFα: tumour necrosis factor factor-alpha; HSPs: heat shock proteins; VEGF: vascular endothelial growth factor; PPARA: peroxisome proliferator activated receptor-α PXR: pregnane X receptor; TTR: transthyretin; BED: Biological Effectors Database; MLP: multilayer perceptron.

Meta-analysis of the embryo freezing transfer interval.

BACKGROUND: The decision of whether frozen embryo transfer (FET) should be performed in the cycle immediately after OPU or at least one cycle later is controversial. FET could improve pregnancy rates in IVF; however, how much time is needed for the endometrium to return to optimal receptivity after ovarian stimulation is not known. METHODS: Electronic search in MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials to identify studies providing data on the influence of the interval between embryo freezing (or OPU) and FET in FET cycles published between January 1, 2007, and February 1, 2020. MAIN FINDINGS: Data analyzed indicated that in the immediate FET cycles, there was a trend to an increased biochemical pregnancy rate (RR = 1.08; CI = 1.00-1.18), whereas the clinical pregnancy rate was somewhat higher, but without reaching statistical significance (RR = 1.07; CI = 0.99-1.15). The live birth rate was similar in the two groups (RR = 1.05; CI = 0.95-1.15), as was the implantation rate (RR = 0.98; CI = 0.83-1.16). Stratifying by embryo stage or FET type (freeze-all or FET after failed fresh transfer) showed no differences. CONCLUSION: Systematically delaying FET does not offer benefits to IVF outcomes. In addition, immediate transfer is associated with a nonsignificant trend to better clinical pregnancy rate and it also avoids the psychological effects of prolonging the stress on prospective parents.

Cervical pregnancy in assisted reproduction: an analysis of risk factors in 91,067 ongoing pregnancies.

RESEARCH QUESTION: What is the frequency of cervical pregnancy in women undergoing assisted reproductive technologies (ART) and what are the risk factors? DESIGN: Case-control study of women undergoing assisted reproductive technology (ART) at 25 private assisted reproduction clinics run by the same group in Spain. Two control groups (tubal ectopic pregnancies and intrauterine pregnancies) were established. The main outcome measure was frequency of cervical pregnancy. Demographic, clinical factors and IVF parameters were assessed for their influence on cervical pregnancy risk. RESULTS: Thirty-two clinical pregnancies were achieved out of 91,067 ongoing pregnancies, yielding a rate of 3.5/10,000. Cervical pregnancies represented 2.02% of all ectopic pregnancies (32/1582). The main risk factors two or more previous pregnancies (OR 2.68; CI 1.18 to 6.07); two or more previous miscarriages (OR 4.21; CI1.7 to 10.43), one or more previous curettages (OR 3.99, CI 1.67 to 9.56), two or more previous curettages (OR 4.71; CI 1.19 to 18.66) and smoking (OR 2.82 CI 1.14 to 6.94). History of caesarean sections and tubal pregnancy was not associated with an elevated cervical pregnancy risk. Infertility conditions and endometrial thickness were similar across the three groups. The proportion of women from whom fewer than 10 oocytes were retrieved was higher in the clinical pregnancy group than in the IUP group. CONCLUSIONS: In ART, the main risk factors for cervical ectopic pregnancy are a history of at least two pregnancies, miscarriages, at least one curettage and smoking. IVF parameters do not seem to influence the development of clinical pregnancies. Cervical pregnancies are less common in ART than previously reported, attributable to improvements in ART; a publication bias in early IVF reports cannot be ruled out.

Oocytes of women who are obese or overweight have lower levels of n-3 polyunsaturated fatty acids compared with oocytes of women with normal weight.

OBJECTIVE: To ascertain whether the oocytes of women who are obese or overweight have a different fatty acid (FA) profile than women with normal weight. DESIGN: Prospective case-control study. SETTING: Two IVF centers. PATIENT(S): A total of 205 women undergoing IVF and intracytoplasmic sperm injection (ICSI) were included in the study, totaling 922 oocytes. INTERVENTION(S): The unfertilized and the immature oocytes from the women who underwent IVF/ICSI were subjected to FA analysis with capillary gas chromatography. Women were classified according their body mass index (BMI) as normal, overweight, or obese. Germinal vesicle oocytes, metaphase I oocytes, and unfertilized metaphase II oocytes were analyzed separately. MAIN OUTCOME MEASURE(S): Fatty acid profile. RESULT(S): A very different oocyte FA pattern was observed for each BMI. Women with normal weight had higher levels of saturated FAs, and lower levels of monosaturated FAs. Women who were obese had lower levels of n-3 polyunsaturated FA, and the lowest n-6:n-3 ratios. Regarding specific FAs, docosahexaenoic acid levels were lower in women with normal weight than in those who are overweight, and in women who are overweight than in those who are obese. The opposite occurred with eicosapentaenoic acid, with the highest levels in women who have normal weight followed by those who are overweight and lower levels in those women who were obese. When FA analysis was restricted to a subset of oocytes, many of these differences persisted. CONCLUSION(S): Our study shows that oocytes from women who are obese or overweight have a different FA composition. This difference in levels could be related to the IVF poor outcome in these women. Therefore, this different composition could suggest that offspring of women who are obese or overweight have an unfavorable milieu even before conception.