Potential effects of COVID-19 on reproductive systems and fertility; assisted reproductive technology guidelines and considerations: a review.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) employs the angiotensin-converting enzyme 2 (ACE2) receptor in the renin-angiotensin system for viral entry. The ACE2 receptor is present in both female and male reproductive systems, and reports of multi-organ involvement have led to uncertainty regarding its effects on the reproductive system and fertility. We review the existing literature regarding the function of ACE2 and the renin-angiotensin system in the female and male reproductive systems to postulate the possible implications of SARS-CoV-2 regarding fertility. Because of the presence of ACE2 in the ovaries, SARS-CoV-2 infection may disrupt ovarian function and hence oocyte quality. Higher expression of ACE2 in the endometrium with age and during the secretory phase raises concern about increased susceptibility to infection during periods of high ACE2 expression. The possibility of vertical transmission and the presence of ACE2 in the placenta and during pregnancy are also discussed. The presence of SARS-CoV-2 RNA in semen is controversial, but impaired semen quality has been found in men with moderate coronavirus disease 2019 infection. Evidence of orchitis and hormonal changes seen in male coronavirus disease 2019 infection may lead to infertility. The implications of these effects on assisted reproductive technology (ART) outcomes are also explored. The ART guidelines from different fertility societies for the management of patients treated with ART are provided. The importance of prioritising 'time-sensitive' patients for ART, counselling patients about the uncertainty and risks of ART, and pregnancy during the pandemic is discussed. Recommendations are also provided for infection control and safe regulation of ART centres and laboratories.