The typical clinical features are: nasal congestion, runny nose, cough, sore throat, headache, fatigue, muscle aches, fever, and viral colds are usually characterized by high fever, fatigue, and muscle aches. For couples who are trying to conceive naturally or through IVF, there are often concerns about whether a cold will affect the sperm and whether it will have an impact on the success rate of pregnancy and the fetus. Generally speaking, a common cold without fever has little effect on human sperm, but a combination of fever and a body temperature above 38°C may have a negative effect on sperm. Semen quality is greatly affected by body temperature, the most suitable temperature for men’s testicles to produce sperm is 35.6-36.0°C, 1-1.5°C lower than the normal body temperature, fever, sauna, commonly used very hot water shower or stay in the sauna for too long, can make the scrotum heated, sperm production is reduced or dead sperm. Studies have shown that heat during sperm meiosis and increased testicular temperature affect sperm density. It can also lead to poor sperm motility and high malformation rates. However, changes in sperm quality caused by short-term fever are reversible. A high fever lasting more than two weeks significantly reduces sperm viability, but sperm viability can return to normal after 1 week of return to normal body temperature. Viral flu is an acute respiratory infection caused by influenza virus, highly contagious, high incidence, easy to cause outbreaks or pandemics, its main transmission through droplets containing the virus, from the incubation period that is contagious, the onset of the strongest contagious within 3 days. Mumps virus is a type of influenza virus that can cause mumps, but can also infect other organs such as testes, ovaries, breast, eyes, inner ear, etc. Viral flu, especially in patients with swollen and painful testes, has a greater impact on the human reproductive system. Inclusions of virus-infected germ cells can be detected in the semen of patients in the acute phase of viral flu, and patients with swollen and painful testes can also suffer from chronic pathological changes in the testes, which can cause testicular atrophy in severe cases, and sometimes also cause azoospermia or severe reduction in sperm count. Because the pathological changes are gradual, it takes about 10-20 years after the acute phase for the maximum damage to the testis to manifest itself gradually. Although the mumps virus has a greater impact on the reproductive system, there is no need to be overly alarmed and the impact on the reproductive system is limited as long as it is not combined with painful swelling of the testicles. What should I do if I get a cold during pregnancy preparation? First of all, you should understand the effect of cold on sperm and not worry too much. If you have a simple common cold without high fever, it will have little effect on the quality of sperm. Secondly, it is recommended to consult the respiratory department of the local hospital and consider the treatment with drugs that affect semen quality. Many patients are worried about the effect of drugs on sperm and fetus, so they refuse to use the drugs, resulting in the aggravation of the cold or even the combination of other complications, which in turn has a greater impact on sperm quality. In addition, for patients with common cold or viral cold accompanied by high fever, it is recommended to temporarily suspend trying to conceive if you are trying to conceive naturally and consider trying to conceive again after the cold has recovered. For patients who are undergoing IVF, if they do not have long lasting high fever or swollen testicles, they can continue IVF and it will have little effect on IVF. If they have long lasting high fever or swollen and painful testicles, it is recommended to consult further at the IVF center for a comprehensive assessment of their condition to determine if they can continue IVF.