Background: As of today, the effect of coronavirus disease 2019 (COVID-19) on male fertility remains unclear. Studies published so far have partly contradictory results, likely due to very small sample sizes and heterogeneous populations. To gain a deeper understanding of the impact of COVID-19 on male fertility, we performed a prospective case–control study, in which we examined the ejaculate of 37 subjects, including 25 subjects in the acute phase of mild COVID-19 and 12 subjects who did not suffer from COVID-19. Determination of semen parameters, severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) qPCR, and infectivity analysis were performed in the acute phase of the disease and in series. Results: Semen parameter values did not differ significantly between subjects with mild COVID-19 and the control group. The serial examination of semen parameters revealed no significant changes between 4, 18, and 82 days after the onset of symptoms. SARS-CoV-2 RNA or infectious particles could not be detected in any ejaculate. Conclusion: Mild COVID-19 seems to have no detrimental effect on semen parameter values.

Purpose: Displaced endometrial receptivity has been discussed as a possible cause of recurrent implantation failure in patients undergoing assisted reproductive technology. The aim of this study was to document our experience with the endometrial receptivity analysis in patients with recurrent implantation failure.Methods: This retrospective cohort study, conducted at the Fertility Centre of the University Hospital, Duesseldorf Germany, presents the results of the endometrial receptivity analysis in 67 patients with recurrent implantation failure and compares the clinical outcome between these 67 patients who underwent a personalized frozen-thawed embryo transfer guided by the results of the endometrial receptivity analysis and 32 patients with recurrent implantation failure who performed a standardized frozen-thawed embryo transfer.Results: The data analysis revealed a displaced endometrial receptivity in 73% (49/67) of all tested patients. Out of these patients, 24% (12/49) were early receptive, 74% (36/49) were pre-receptive, and 2% (1/49) were post-receptive. Comparison of pregnancy rate, clinical pregnancy rate, and live-birth rate between personalized (49%, 39%, 27%, respectively) and standardized embryo transfer (44%, 31%, 19%, respectively) reveals no statistically significant difference. In both groups, patients had an average of four unsuccessful embryo transfers.Conclusion: In this cohort of patients with recurrent implantation failure, the endometrial receptivity analysis showed a high incidence of displaced endometrial receptivity. However, a personalized embryo transfer did not increase reproductive outcome. Displaced endometrial receptivity might not be the main cause for recurrent implantation failure in this cohort.

Background/Objectives: In this observational prospective cohort study, conducted at the Fertility Centre of the University Hospital, Duesseldorf Germany, the spontaneous reversal capacity and the effect of waiting time on an adverse vaginal microbiome profile in subfertile patients were investigated. Methods: Vaginal swabs of 76 patients were obtained before starting a fertility treatment using a commercially available test to perform a microbiome analysis. Patients with a favorable microbiome profile (“medium” or “high profile”) according to the manufacturer’s algorithm proceeded with the fertility treatment. Patients with an unfavorable microbiome profile (“low profile”) postponed their fertility treatment and were sampled up to four times in each successive cycle or until a shift to a more favorable profile was detected. Results: Initially, 54/76 subjects had a high or medium profile and 23/76 had a low profile. Within 3 months, 75% of patients with an initial low profile shifted to a more favorable profile (7/23 dropouts). The presence of Lactobacillus crispatus in the initial sample was associated with a higher likelihood of a spontaneous shift to a more favorable profile. Conclusions: The vaginal microbiome is subject to strong fluctuations. Even an unfavorable microbiome profile can develop into a favorable microbiome profile within a few months without treatment.