Disposables used cumulatively in routine IVF procedures could display toxicity.

STUDY QUESTION: Is there a cumulative toxicity of disposables used in IVF procedures? SUMMARY ANSWER: A toxicity may be detected when consumables are used cumulatively, while no toxicity is detected when the same consumables are used and tested individually. WHAT IS KNOWN ALREADY: Many components of items used in IVF laboratories may impair human embryonic development. Consequently, it is necessary to screen all reagents and materials which could be in contact with gametes and embryos. Toxicity tests, such as the mouse embryo assay and the human sperm motility assay (HSMA), are used by manufacturers as quality control tools to demonstrate the safety of their products. This evaluation is currently individually performed for each single consumable. However, during an IVF cycle, several devices are used sequentially, potentially creating a cumulative exposure to chemical contaminants, which could not be detected for individually tested consumables. STUDY DESIGN, SIZE, DURATION: The objective of this observational study conducted from March 2021 to October 2022 was to evaluate with the HSMA methodology if there was a cumulative toxicity when several disposables are sequentially used. Fourteen categories of consumables currently used in routine IVF procedures were studied, which included devices used for sperm and oocyte collection (cups, condoms, and oocyte aspiration needles), manipulation (flasks, tubes, tips, pipettes, embryo transfer catheters, syringes, and gloves), culture (dishes), and storage (straws). PARTICIPANTS/MATERIALS, SETTING, METHODS: After obtaining patient consent, the surplus semen assessed as having normal parameters according to the World Health Organization 2010 criteria were used to perform the HSMAs. First, each consumable was tested individually. Then, associations of three, four, and five consumables, previously validated as non-toxic when tested individually, were analyzed. HSMAs were conducted three times to ensure reproducibility, with a defined toxicity threshold of a sperm motility index (SMI) below 0.85 in at least two of three tests. MAIN RESULTS AND THE ROLE OF CHANCE: Thirty-six references of disposables were first individually tested across 53 lots. Forty-nine (92%) demonstrated compliance. However, four (8%) devices revealed toxicity: one lot of 1 ml syringes, two lots of sperm cups, and one lot of 25 cm2 flasks. These four references were excluded from the IVF routine procedures. A total of 48 combinations of consumables were assessed, involving 41 lots from 32 references that were previously individually tested. Among the evaluated combinations, 17 out of 48 (35%) associations exhibited toxicity with a SMI below 0.85 for two of the three tests (n = 8) or all the three tests (n = 9). Notably, three out of 17 (18%) of the three-consumable associations, five out of 16 (31%) of the four-consumable associations, and nine out of 15 (60%) of the five-consumable associations were found not compliant. The toxicity did not originate from a single consumable, because only consumables that were individually pre-validated as non-toxic were included in the combinations, but the toxicity had a cumulative origin. The risk of cumulative toxicity increased with the number of consumables included in the association (Cochran-Mantel-Haenszel statistic, P = 0.013). LIMITATIONS, REASONS FOR CAUTION: The high proportion of non-compliant combinations of disposables can be attributed directly to the extreme rigorous extraction conditions employed during the tests, which could deviate from the conditions encountered in routine clinical use. Also, the methodology employed in the HSMAs (e.g. toxicity extraction duration, sperm concentrations, and protein supplementation of the medium) can influence the sensitivity of the tests. WIDER IMPLICATIONS OF THE FINDINGS: This study highlights the significance of performing toxicity testing on devices before introducing them into clinical practice. Disposables should be tested individually to detect immediate toxicities and also in combination. Our results advocate rationalizing the number of consumables used in each IVF procedure and re-evaluating the use of glass consumables. STUDY FUNDING/COMPETING INTEREST(S): This study received fundings from GCS Ramsay Santé pour l'Enseignement et la Recherche (Paris, France) and the Centre de Biologie Médicale BIOGROUP (Le Chesnay-Rocquencourt, France). The authors declare that they have no conflict of interest that could be perceived as prejudicing the impartiality of the reported research. TRIAL REGISTRATION NUMBER: N/A.

Evaluation of SARS-CoV-2 in semen, seminal plasma, and spermatozoa pellet of COVID-19 patients in the acute stage of infection.

To date, there is limited information about the presence of SARS-CoV-2 in semen especially in the acute phase of the infection. While available data from cohort studies including a total of 342 patients in the acute or recovery phase of the infection are reassuring, one study mentioned detecting virus in the semen of 6/38 COVID-19 patients. Here we assessed SARS-CoV-2 presence in the semen of COVID-19 positive patients in the acute stage of infection, within 24 hours of the positive nasopharyngeal swabs. Semen, seminal plasma and spermatozoa pellet were screened for SARS-CoV-2 and manual or airborne contamination during semen sampling. Among the 32 COVID-19 volunteers, the median interval from the onset of symptoms to semen collection was 4 days [IQR: 0-8]. Only one presented positive SARS-CoV-2 PCR in semen and seminal plasma fractions, although the spermatozoa pellet was negative. Viral cultures were all negative. We observed slightly higher concentrations of bacterial DNA in the SARS-CoV-2 positive specimen than in all negative samples. The bacteria identified neither confirm nor rule out contamination by oropharyngeal secretions during collection. SARS-CoV-2 was rarely present in semen during the acute phase of the disease. This very rare situation could be connected to oral or manual contamination during semen collection. The possible presence of SARS-CoV-2 in semen calls for nasopharyngeal viral testing and strict hygiene protocols during semen collection before assisted reproductive attempts.

Live birth after intrauterine insemination: is there an upper cut-off for the number of motile spermatozoa inseminated?

RESEARCH QUESTION: To date, most studies have investigated the minimum number of spermatozoa available for intrauterine insemination (IUI), with no data on the maximum number of motile spermatozoa inseminated (NMSI) having been published. This study aimed to determine whether an upper cut-off for the NMSI during IUI exists above which the live birth rate (LBR) is negatively affected. DESIGN: Retrospective analysis of autologous IUI cycles performed between January 2010 and July 2018 in women <43 years old with a NMSI >1 million. The main outcome was the LBR per IUI cycle as a function of the NMSI. RESULTS: A total of 2592 IUI cycles performed in 1017 couples were included. The LBR increased with NMSI up to 30 million without any upper threshold (AUC = 0.5441). The LBR per IUI cycle were 14.5%, 17.9% and 22.7% for NMSI of >1 to ≤10, >10 to ≤20 and >20 to ≤30 million, respectively (P = 0.003). By univariate analysis, the NMSI, female age, number of mature follicles and oestradiol concentrations on day of ovulation triggering, cycle number and infertility aetiology influenced the LBR. Multivariate analysis showed that the LBR was 1.49 and 1.78 times higher when IUI was performed with a NMSI >10 to ≤20 million (odds ratio [OR] 1.49; 95% confidence interval [CI] 1.10-2.02]) and >20 to ≤30 million (OR 1.78; 95% CI 1.08-2.94), respectively, compared with IUI with a NMSI >1 to ≤10 million. CONCLUSIONS: The LBR after IUI can be optimized by inseminating a maximum of motile spermatozoa up to 30 million. Thus, in this specific cohort, IUI preparations should not be diluted when more than 10 million motile spermatozoa are obtained.

Women infected with human immunodeficiency virus type 1 have poorer assisted reproduction outcomes: a case-control study.

OBJECTIVE: To compare the efficacy of assisted reproductive technology (ART) in women infected with human immunodeficiency virus type 1 (HIV-1) versus HIV-negative controls. DESIGN: Retrospective case-control study. SETTING: University hospital ART unit. PATIENT(S): Eighty-two women infected with HIV-1 and 82 women as seronegative controls. INTERVENTION(S): Ovarian stimulation, oocytes retrieval, standard in vitro fertilization (IVF) or intracytoplasmic sperm injection, embryo transfer. MAIN OUTCOME MEASURE(S): Clinical pregnancies and live-birth rates. RESULT(S): After oocyte retrieval, all women infected with HIV-1 infected were matched 1:1 to HIV-negative controls according to the following criteria: date of ART attempt, age, parity, main cause of infertility, ART technique, and rank of attempt. Only the first IVF cycle during the study period was considered for each couple. We found no statistically significant differences between the two groups for ovarian stimulation data, fertilization rate, or average number of embryos transferred. The clinical pregnancy rate per transfer was statistically significantly lower for the cases compared with the controls (12% vs. 32%), as were the implantation rate (10% vs. 21%) and the live-birth rate (7% vs. 19%). CONCLUSION(S): In one of the largest studies to pair six factors that influence the results of ART, HIV infection in women was associated with poorer outcomes after ART. These results suggest that women with controlled HIV-1-infection should be counseled not to delay ART in cases of self-insemination failure or other causes of infertility. Fertility preservation by vitrification of oocytes in women whose pregnancy should be delayed may be an important future consideration.

Is the nuclear status of an embryo an independent factor to predict its ability to develop to term?

OBJECTIVE: To determine the prognostic impact of the embryo nuclear status at day 2 among other major morphologic parameters (first cleavage at day 1, number of blastomeres and anuclear fragmentation at day 2) on the birth rate. DESIGN: Retrospective study. SETTING: Hospital IVF department. PATIENT(S): Women undergoing 1,629 day 2 transfers of 2,732 embryos from May 2006 to November 2008. INTERVENTION(S): Four groups according to the embryo nuclear status. MAIN OUTCOME MEASURE(S): Implantation, miscarriage, and birth rates. RESULT(S): Univariate analysis indicated significantly higher birth rates when all blastomeres were mononucleated (15.0%) compared with embryos with not all blastomeres mononucleated (9.2%), embryos without any visible nucleus (7.7%), and embryos where at least one blastomere was multinucleated (4.2%). Multivariate analysis found significant decreased birth rates when multinucleated blastomeres were observed. CONCLUSION(S): Blastomere nuclear status should be added to the kinetic and morphologic criteria traditionally used at day 2 to assess human embryo quality. The presence of multinucleated blastomeres has a negative impact on birth potential. The results argue for integrating the blastomere nuclear status at day 2 with the kinetic and morphologic criteria traditionally used to define the best embryo to transfer. Embryos with a single visible nucleus in all blastomeres should be given priority for transfer when available.

Intracytoplasmic morphologically selected sperm injection (IMSI) after repeated IVF or ICSI failures: a prospective comparative study.

OBJECTIVE: Sperm morphology plays a significant role in assisted reproductive technologies and is associated with high implantation rates. The objective of this study was to evaluate the outcome of intracytoplasmic morphologically selected sperm injection (IMSI) after repeated failures of conventional in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) techniques. STUDY DESIGN: In a prospective study in which couples acted as their own controls, 75 infertile couples were offered IMSI after at least two previous IVF or ICSI failures. The main outcome measures were embryo quality and number of blastocysts obtained. RESULTS: The percentage of top quality embryos obtained at day 2 was increased in IMSI compared to IVF/ICSI cycles (89.8% versus 79.8%; p=0.009). Extended embryo culture was possible in 41.3% of IMSI cycles versus 26.7% of IVF/ICSI cycles (p=0.04), and the mean number of blastocysts obtained was higher in IMSI cycles (1.5±1.9) than in IVF/ICSI cycles (1.0±1.2) (p=0.03). Moreover, IMSI resulted in clinical pregnancy and birth rates of respectively 29.3% and 18.6%. CONCLUSION: After two or three IVF/ICSI failures, IMSI seems to give better embryo quality and more blastocysts, which allow more embryo transfers at the blastocyst stage. This study supports the use of sperm ultramorphology examination as an independent test to be proposed after repeated IVF or ICSI failures.

[The process of X inactivation in the mouse]. / Le modèle de l'inactivation du chromosome X chez la souris.

X chromosome inactivation (XCI) is an excellent model for studying how epigenetic marks are initiated during early embryogenesis. XCI is an essential process that takes place in females, leading to dosage compensation between males and females. In mouse, it occurs in two waves: the first one is paternally imprinted, during the preimplantation period and the second one occurs in a random fashion. We provide here an update of the main molecular steps and hypothesis underlining this complex process.

Optimal timing for oocyte denudation and intracytoplasmic sperm injection.

Objectives. To analyze the impact of oocyte denudation and microinjection timings on intracytoplasmic sperm injection (ICSI) outcomes. Study Design. We included ICSI cycles with the following parameters: rank 1 or 2, female age <36 years, male factor infertility, long protocol using GnRH agonist and rFSH for ovarian stimulation, and use of freshly ejaculated sperm (n = 110). Several ICSI parameters were analyzed according to the time between oocyte retrieval and denudation (T(1)) and the time between denudation and ICSI (T(2)) using a statistical logistic regression analysis. Results. Neither T(1) nor T(2) had a significant influence on the Metaphase II (MII) rate but the fertilisation rate (FR) showed a significant improvement when T(1) was longer (optimal results at T(1) = 3 hours) while FR significantly decreased with the increase of T(2). Optimal implantation (IR) and pregnancy (PR) rates were obtained when T(1) was around 2 hours. Conclusion. Incubation of oocytes around 2 hours between retrieval and denudation may not increase MII rate but appears to lead to the optimal combination of FR and IR.