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Background and Aims The severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) is known to affect multiple organs by binding to angiotensin‐converting enzyme 2 receptors and might therefore affect male fertility. This review aims to collect all original articles on the effects of SARS‐CoV‐2 infection on male fertility, including the duration of time after infection required for these effects to begin to manifest and recommend how clinicians should approach cases with a recent illness. Methods This review was developed according to the preferred reporting items for systematic reviews and meta‐analyses guidelines. The search string was applied to four online databases—namely Pubmed, Embase, Medline, and the Cochrane COVID‐19 Register—and screened using the online tool Covidence.org . Articles were eligible for inclusion if they were cohort studies involving a healthy male population diagnosed with COVID‐19, each of whom had semen samples collected before and after the infection or two different semen samples collected after the diagnosis. Results Nine cohort studies were eventually included. Five articles had pre‐ and post‐COVID‐19 data while four had two sets of post‐COVID‐19 data. The three largest studies found a statistically significant decrease in all semen parameters when waiting less than 3 months from diagnosis before sample collection, and no significant differences in results when the ejaculate was analyzed more than 3 months after recovery. One study compared the COVID‐19 patients with a control group and found a significant decrease in semen parameters in the COVID‐19 group. Conclusion Spermatogenesis seems to be affected by SARS‐CoV‐2 infection, but the impact tends to reverse within 3–4 months. It is still unclear why male fertility is affected by SARS‐CoV‐2 infection, and it might be the result of several different components. Clinicians should consider recent SARS‐CoV‐2 infection as a possible reason for the low semen quality of patients' semen samples, and might therefore need to collect new samples after 4 months before further treatment.

Here we have summarized what is currently known about menstruating animal species with special emphasis on non-primate species: length of their menstrual cycle, ovulation, implantation, placentation, decidualization, and endometrial characteristics. Having an overview of all the possible animal models that can be used to study menstruation and the menstrual cycle could be useful to select the one that better matches the needs of the individual research projects. The most promising species to study menstruation seems to be the spiny mouse Acomys cahirinus. It is a rodent that could be easily held in the existing laboratory facilities for rats and mice but with the great advantage of having spontaneous menstruation and several human-like menstrual cycle characteristics. Among the species of menstruating bats, the black mastiff bat Molossus ater and wild fulvous fruit bat Rousettus leschenaultii are the ones presenting the most human-like characteristics. The elephant shrew seems to be the less suitable species among the ones analyzed. The induced mouse model of menstruation is also presented as an adaptable alternative to study menstruation.

The purpose of this study is to describe a low-cost and simply made instrument capable of measuring the total CO content of microliter volumes of biological fluids utilizing a commercially available CO sensor based on a NDIR detector. The described instrument is based on transformation of dissolved HCO to CO by acidification and subsequent measurement of the produced CO. The instrument has a linear response in the range 0.025-10 μmol HCO, which enables measurements in fresh urine and plasma samples down to 5 μl. The values from plasma were compared to measurements made on 65 μl whole blood in an automatic blood gas analyzer and found not to differ significantly. Compared to currently commercially available instruments applying the same principles to measure total CO, this study provides a simple and robust alternative which even can be used on smaller sample volumes.