What is the survival rate of sperm in the body?

We all know that the birth of a baby starts with a tiny fertilized egg, which is mainly formed by the combination of sperm and egg cells. How does the sperm survive in the woman's body before entering the egg cell? How does it wait for an opportunity to meet? Nowadays, it is easy for men to have a low sperm survival rate in the body, which seriously affects their normal pregnancy.

1. Sperm retention time in the female reproductive tract:

The pH of acidic vaginal secretions is usually 3.5-4. Although in theory as long as there is one living sperm, fertilization can occur, in reality, in the acidic environment of the vagina, most sperm die soon after entering the vagina. Only with a certain amount of semen as a buffer can the survival time of a very small number of sperm with strong vitality be extended and have the opportunity to enter the uterus and fertilize.

Without the sacrifice of a large number of sperm, and without a certain amount of semen buffering to improve the acid-base environment in the vagina, it is impossible for a single sperm or a very small number of sperm to survive and fertilize in the acidic environment of the vagina.

Under normal circumstances, the survival time of sperm in the vagina is: 90% die within 2 hours after sexual intercourse; after 36 hours, even the dead ones cannot be seen. In the vagina of a pregnant woman, the stronger the acidity, the faster the sperm die.

2. Sperm retention time in the cervix:

Changes in the pH of cervical mucus have a great impact on sperm penetration. When the pH is less than 6.5, sperm activity stops, when the pH is 7, there is a slight ability to penetrate, when the pH is 7.5, the ability to penetrate is normal, and when the pH is 8, the ability to penetrate is stronger.

There is a lot of mucus blocking the external opening of the cervix, which prevents many sperm from penetrating and causing them to die outside. Cervical mucus is thick and tough just after menstruation; near ovulation, due to the increase of estrogen in the blood, the mucus becomes more abundant, clearer, and more stringy; during ovulation, the mucus is more abundant, clearer, and flows out, making it easier for sperm to penetrate.

Sperm penetrates cervical mucus by enzyme hydrolysis. Chymotrypsin and hyaluronidase can hydrolyze cervical mucus, reduce viscosity, and eliminate sticky thread formation, which is conducive to the passage of sperm.

Generally speaking, the survival time of sperm in the cervix is: in the cervix, sperm can be found in the cervical mucus 15 minutes after sexual intercourse; one hour later, sperm enters the internal opening; in the uterine cavity, sperm can be found in the uterine cavity one hour after sexual intercourse, after 6 hours, all sperm are active, after 12 hours, 5/6 of the sperm are still alive, after 36 hours, 1/4 of the sperm are still alive, and after three days, there are no live sperm. But sometimes, individual sperm can survive for a particularly long time.

There may be active sperm in the fallopian tube 14 hours after sexual intercourse. If there are still active sperm afterwards, generally speaking, sperm around 14 days old are the most active, and some may even enter the abdominal cavity. Those that move more slowly will be pushed back into the uterine cavity by the cilia flow.