The impact of past COVID-19 infection on pregnancy rates in frozen embryo transfer cycles.

PURPOSE: To study the effect of SARS-CoV-2 infection on pregnancy rates in frozen embryo transfer (FET) cycles. METHODS: A retrospective cohort study including women under the age of 42 with documented SARS-CoV-2 infection up to 1 year prior to treatment, undergoing FET cycles in the first half of 2021, with transfer of embryos generated prior to the infection. Controls were SARS-CoV-2 non-diagnosed, non-vaccinated women matched by age, number, and day of embryo transfer. Demographic and cycle characteristics and outcomes were compared. RESULTS: Forty-one recovered women and 41 controls were included. Pregnancy rates were 29% and 49% respectively (p = 0.070). Stratification by time from SARS-CoV-2 infection to transfer into ≤ 60 and > 60 days revealed a difference in pregnancy rates, with women in the COVID group having lower pregnancy rates if infected in proximity to the transfer (21% vs. 55%; p = 0.006). In a logistic regression model, infection was a significant variable (p = 0.05, OR 0.325, 95% CI 0.106-0.998). Logistic regression applied on the subgroup of women infected in proximity to the transfer further strengthened the univariate results, with COVID-19 remaining a significant parameter (p = 0.005, OR 0.072, 95% CI 0.012-0.450). CONCLUSIONS: In FET cycles of patients with past SARS-CoV-2 infection, in which oocytes were retrieved prior to infection, decreased pregnancy rates were observed, specifically in patients who recovered less than 60 days prior to embryo transfer. Pending further studies, in cases of FET cycles with limited number of embryos, postponing embryo transfer for at least 60 days following recovery from COVID-19 might be considered when feasible.

IVF under COVID-19: treatment outcomes of fresh ART cycles.

STUDY QUESTION: Does prior severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection in women undergoing fertility treatments affect the outcomes of fresh ART cycles? SUMMARY ANSWER: SARS-CoV-2 infection does not affect fresh ART treatment outcomes, except for a possible long-term negative effect on oocyte yield (>180 days postinfection). WHAT IS KNOWN ALREADY: A single previous study suggested no evidence that a history of asymptomatic or mild SARS-CoV-2 infection in females caused impairment of fresh ART treatment outcomes. STUDY DESIGN, SIZE, DURATION: Retrospective cohort study, including all SARS-CoV-2 infected women who underwent fresh ART cycles within a year from infection (the first cycle postinfection), between October 2020 and June 2021, matched to non-diagnosed controls. PARTICIPANTS/MATERIALS, SETTING, METHODS: Patients from two large IVF units in Israel who were infected with SARS-CoV-2 and later underwent fresh ART cycles were matched by age to non-diagnosed, non-vaccinated controls. Demographics, cycle characteristics and cycle outcomes, including oocyte yield, maturation rate, fertilization rate, number of frozen embryos per cycle and clinical pregnancy rates, were compared between groups. MAIN RESULTS AND THE ROLE OF CHANCE: One hundred and twenty-one infected patients and 121 controls who underwent fresh ART cycles were included. Oocyte yield (12.50 versus 11.29; P = 0.169) and mature oocyte rate (78% versus 82%; P = 0.144) in all fresh cycles were similar between groups, as were fertilization rates, number of frozen embryos per cycle and clinical pregnancy rates (43% versus 40%; P = 0.737) in fresh cycles with an embryo transfer. In a logistic regression model, SARS-CoV-2 infection more than 180 days prior to retrieval had a negative effect on oocyte yield (P = 0.018, Slope = -4.08, 95% CI -7.41 to -0.75), although the sample size was small. LIMITATIONS, REASONS FOR CAUTION: A retrospective study with data that was not uniformly generated under a study protocol, no antibody testing for the control group. WIDER IMPLICATIONS OF THE FINDINGS: The study findings suggest that SARS-CoV-2 infection does not affect treatment outcomes, including oocyte yield, fertilization and maturation rate, number of good quality embryos and clinical pregnancy rates, in fresh ART cycles, except for a possible long-term negative effect on oocyte yield when retrieval occurs >180 days post-SARS-CoV-2 infection. Further studies are warranted to support these findings. STUDY FUNDING/COMPETING INTEREST(S): None. TRIAL REGISTRATION NUMBER: 0010-21-HMC, 0094-21-ASF.