Coronavirus Disease 2019 (COVID-19) Vaccination and Assisted Reproduction Outcomes: A Systematic Review and Meta-analysis.

OBJECTIVE: To assess the association between coronavirus disease 2019 (COVID-19) vaccination and female assisted reproduction outcomes through a systematic review and meta-analysis. DATA SOURCES: We searched Medline (OVID), EMBASE, Web of Science, Cochrane Library, and ClinicalTrials.gov on January 11, 2023, for original articles on assisted reproduction outcomes after COVID-19 vaccination. The primary outcome was rates of clinical pregnancy; secondary outcomes included number of oocytes retrieved, number of mature oocytes retrieved, fertilization rate, implantation rate, ongoing pregnancy rate, and live-birth rate. METHODS OF STUDY SELECTION: Two reviewers independently screened citations for relevance, extracted pertinent data, and rated study quality. Only peer-reviewed published studies were included. TABULATION, INTEGRATION, AND RESULTS: Our query retrieved 216 citations, of which 25 were studies with original, relevant data. Nineteen studies reported embryo transfer outcomes, with a total of 4,899 vaccinated and 13,491 unvaccinated patients. Eighteen studies reported data on ovarian stimulation outcomes, with a total of 1,878 vaccinated and 3,174 unvaccinated patients. There were no statistically significant results among our pooled data for any of the primary or secondary outcomes: clinical pregnancy rate (odds ratio [OR] 0.94, 95% CI 0.88-1.01, P =.10), number of oocytes retrieved (mean difference -0.26, 95% CI -0.68 to 0.15, P =.21), number of mature oocytes retrieved (mean difference 0.31, 95% CI -0.14 to 0.75, P =.18), fertilization rate (OR 0.99, 95% CI 0.87-1.11, P =.83), implantation rate (OR 0.92, 95% CI 0.84-1.00, P =.06), ongoing pregnancy rate (OR 0.95, 95% CI 0.86-1.06, P =.40), or live-birth rate (OR 0.95, 95% CI 0.78-1.17, P =.63). A subanalysis based on country of origin and vaccine type was also performed for the primary and secondary outcomes and did not change the study results. CONCLUSION: Vaccination against COVID-19 is not associated with different fertility outcomes in patients undergoing assisted reproductive technologies. SYSTEMATIC REVIEW REGISTRATION: PROSPERO, CRD42023400023.

Dose-Dense Chemotherapy Regimen for Breast Cancer Associated with Significant Decline in Ovarian Reserve.

Purpose: To determine the impact of dose-dense chemotherapy administration on ovarian reserve in women undergoing treatment for breast cancer. Patients and Methods: We conducted a retrospective cohort study of reproductive age women who underwent dose-dense chemotherapy regimens with doxorubicin hydrochloride and cyclophosphamide with or without paclitaxel for a new diagnosis of breast cancer. We compared pre- and post-treatment serum antimullerian hormone (AMH) levels and assessed changes in AMH over time. Results: Fifty-seven patients met inclusion criteria. Median pre-treatment AMH was 2.9 ng/mL, whereas post-treatment AMH was 0.1 ng/mL, demonstrating a dramatic reduction in AMH levels after treatment with a dose-dense regimen. This change was independent of age and was sustained over 12 months from treatment completion. Conclusions: Dose-dense chemotherapy regimens for breast cancer lead to marked and sustained decreases in AMH irrespective of patient age.

Idiopathic early ovarian aging: is there a relation with premenopausal accelerated biological aging in young women with diminished response to ART?

PURPOSE: To evaluate whether young women with idiopathic early ovarian aging, as defined by producing fewer oocytes than expected for a given age over multiple in vitro fertilization (IVF) cycles, have changes in telomere length and epigenetic age indicating accelerated biological aging (i.e., increased risk of morbidity and mortality). METHODS: A prospective cohort study was conducted at two Danish public fertility clinics. A total of 55 young women (≤ 37 years) with at least two IVF cycles with ≤ 5 harvested oocytes despite sufficient stimulation with follicle-stimulating hormone (FSH) were included in the early ovarian aging group. As controls, 52 young women (≤ 37 years) with normal ovarian function, defined by at least eight harvested oocytes, were included. Relative telomere length (rTL) and epigenetic age acceleration (AgeAccel) were measured in white blood cells as markers of premenopausal accelerated biological aging. RESULTS: rTL was comparable with a mean of 0.46 (± SD 0.12) in the early ovarian aging group and 0.47 (0.14) in the normal ovarian aging group. The AgeAccel of the early ovarian aging group was, insignificantly, 0.5 years older, but this difference disappeared when adjusting for chronological age. Sub-analysis using Anti-Müllerian hormone (AMH) as selection criterion for the two groups did not change the results. CONCLUSION: We did not find any indications of accelerated aging in whole blood from young women with idiopathic early ovarian aging. Further investigations in a similar cohort of premenopausal women or other tissues are needed to fully elucidate the potential relationship between premenopausal accelerated biological aging and early ovarian aging.

Inhibition of LINE-1 retrotransposition represses telomere reprogramming during mouse 2-cell embryo development.

PURPOSE: To investigate whether inhibition of LINE-1 affects telomere reprogramming during 2-cell embryo development. METHODS: Mouse zygotes were cultured with or without 1 µM azidothymidine (AZT) for up to 15 h (early 2-cell, G1/S) or 24 h (late 2-cell, S/G2). Gene expression and DNA copy number were determined by RT-qPCR and qPCR respectively. Immunostaining and telomeric PNA-FISH were performed for co-localization between telomeres and ZSCAN4 or LINE-1-Orf1p. RESULTS: LINE-1 copy number was remarkably reduced in later 2-cell embryos by exposure to 1 µM AZT, and telomere lengths in late 2-cell embryos with AZT were significantly shorter compared to control embryos (P = 0.0002). Additionally, in the absence of LINE-1 inhibition, Dux, Zscan4, and LINE-1 were highly transcribed in early 2-cell embryos, as compared to late 2-cell embryos (P < 0.0001), suggesting that these 2-cell genes are activated at the early 2-cell stage. However, in early 2-cell embryos with AZT treatment, mRNA levels of Dux, Zscan4, and LINE-1 were significantly decreased. Furthermore, both Zscan4 and LINE-1 encoded proteins localized to telomere regions in 2-cell embryos, but this co-localization was dramatically reduced after AZT treatment (P < 0.001). CONCLUSIONS: Upon inhibition of LINE-1 retrotransposition in mouse 2-cell embryos, Dux, Zscan4, and LINE-1 were significantly downregulated, and telomere elongation was blocked. ZSCAN4 foci and their co-localization with telomeres were also significantly decreased, indicating that ZSCAN4 is an essential component of the telomere reprogramming that occurs in mice at the 2-cell stage. Our findings also suggest that LINE-1 may directly contribute to telomere reprogramming in addition to regulating gene expression.

Epigenetics and Female Reproductive Aging.

With more women than ever waiting until a more advanced age to have children, there exists a newfound urgency to identify the various implications aging has on human reproduction, and understand the disrupted biological processes that result in these changes. In this review, we focus on one recent area of study: the age related epigenetic changes that have been found in female reproductive organs, and the effect these changes may contribute to reproductive outcomes.