One of the biggest concerns of women and men of reproductive age, is whether COVID-19 disease or the vaccine can affect female or male fertility and their chances of conceiving. Available data on the exact effects of COVID-19 on fertility are still scarce but, in this article, we review current evidence available.
How does the COVID-19 infection work?
The COVID-19 virus, known as SARS-CoV-2, is highly infectious, in most cases through coughing, sneezing and talking, or by contact with contaminated objects. The incubation period is between 5.2 days and 12.5 days.
The virus enters human cells through a structure known as the ACE2 receptor. ACE2 receptors are concentrated in certain cell types, tissues, and organs of the body (lungs, bowel, heart, eyes, kidney, brain, etc) and regulate basic functions, including male and female reproductive systems. In women, these include maturation of follicles, production of ovarian hormones, development of eggs, ovulation and endometrial regeneration. In men, ACE2 regulates testicular function, sperm function and may be important for embryo quality. ACE2 receptor is more abundant in male reproductive system than female.
As the COVID-19 virus enters cells by binding to the ACE2 receptor, researchers thought that reproductive cells and/or tissues expressing this receptor are potentially vulnerable to the virus and their functions may be disturbed.
Symptoms of COVID-19
The spectrum of symptoms in COVID-19 infected patients ranges from:
- asymptomatic to mild (flu-like symptoms) in 81% of the cases,
- severe in 14% (hospitalisation and oxygen support),
- critical in 5% (mechanical ventilation),
- with a case fatality rate of 2.3–3%.
Severity of the disease is related to the patient’s age and comorbidities. Patients over 60 years of age with co-morbidities such as diabetes and/or hypertension have the worst prognosis. 1
Impact of COVID-19 on female fertility
The evidence of impact of COVID-19 on eggs is still limited. A study3 described two women who underwent ovarian stimulation and tested positive for SARS-CoV-2 infection by PCR test on the day of egg collection. The viral RNA was not detected in their eggs.
In women, a severe acute illness - like COVID-19 - may alter the hypothalamic-pituitary gonadal (HPG) axis function, decreasing the endogenous production of oestrogens and progesterone. To date, there are no published studies examining the effect of COVID-19 on sex-related hormone levels in female patients.
There is still limited data about the potential impact of COVID-19 on female fertility, especially long term. To our knowledge, at this moment, it seems female gonads and eggs are not affected.
Impact of COVID-19 on male fertility
The impact of COVID-19 on male fertility is more likely than in female fertility. Other viruses, such as hepatitis B, mumps, and HIV can enter the male reproductive system and may impair fertility by causing orchitis (an inflammation of one or both testicles).
A recent study of men with COVID-19 reported that 19% of participants experienced scrotal discomfort, comparable to that with orchitis. Other aspects of the viral infection (fever, inflammation and dysregulation of the HPG axis) may affect testosterone secretion and sperm production. Oxidative stress as a result of COVID-19 could also increase sperm DNA fragmentation.1 However, available data is still scarce and more studies are required to evaluate the impact of SARS-CoV-2 on male fertility, particularly long term.
The impact of COVID-19 on female and male fertility still needs further research. Whilst, at the moment, it seems fertility is not affected by SARS-CoV-2 infection, more information is required about the long term impact on reproductive function.
Written on 19th January 2021
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