Objective: To investigate whether prior COVID-19 infection and time interval after infection affect the in vitro fertilization (IVF) outcomes. Design: A prospective observational cohort. Setting: Reproductive center in China. Population: Participants recovered from COVID-19 and healthy controls. Methods: All participants received normal IVF treatment. The oocyte and embryo quality as well as pregnancy outcome data were collected and analyzed. Main outcome measure: Oocytes and embryo quality, clinical pregnancy outcomes. Results: The oocyte and embryo quality were comparable between the two groups, including the number of oocytes, 2PN zygotes, fertilization rate, cleavage embryos, day 3 good-quality embryos, blastocyst formation rate, and good-quality blastocysts. Nevertheless, the study group exhibited more degenerated oocytes (0.15±0.40 vs. 0.10±0.33, P=0.035). Further regression analysis indicated that prior COVID-19 infection is positively related to the number of degenerated oocytes (Adjusted β: 0.06, 95% confidential interval (CI): 0 -0.10, P=0.032). No significant differences were observed in clinical pregnancy rate, implantation rate, early miscarriage rate, ectopic pregnancy rate, and ongoing pregnancy rate. Similarly, we observed no difference in oocyte and embryo quality as well as pregnancy outcomes across various post-infection time intervals. Conclusions: Preceding COVID-19 could increase the number of degenerated oocytes. However, it does not affect subsequent pregnancy outcomes. Additionally, post-infection time interval plays no significant role in IVF outcomes.

Background and Purpose: COVID-19 patients treated with RAAS blockers are among the patients at highest risk of poor outcome. ACE2 is the functional receptor for SARS-CoV-2. Animal studies suggest that RAAS blockers might increase the expression of ACE2 and potentially increase the risk of SARS-Cov-2 infection. Experimental Approach and Key Results: The effect of ACE inhibitor treatment on the incidence of pneumonia in non-COVID-19 patients was analyzed in 25 studies (330,780 patients). ACE inhibitor use was associated with a 27% reduction of pneumonia risk (OR: 0.73, p<0.001). Pneumonia related death cases in ACE inhibitor treated non-COVID-19 patients were reduced by 27% (OR: 0.73, p=0.004). ARB treatment was analyzed in 10 studies (275,621 non-COVID-19 patients). The risk of pneumonia was not different between patients who did or did not use ARBs. Pooled results from 16 studies in 22,333 COVID-19 patients showed that COVID-19 related server adverse clinical outcomes (admission to ICU, need for assisted ventilation or death) were reduced by 26% when using RAAS blocking agents (OR=0.74, p=0.04). Pooled results from 10 studies in 11,514 COVID-19 patients showed that RAAS blockede reduces all-cause mortality by 41% (OR=0.59, p=0.01). Conclusion and Implications: Given the weak evidence coming from animal studies and the clear beneficial data of ACE inhibition in non-COVID-19 patients and the promising data in COVID-19 patients, the use of RAAS blocking agents in patients with SARS-CoV-2 infection is justified and should be maintained. Further clinical studies analysing ARBs and ACE inhibitors separately in COVID-19 patients are needed.