How long can sperm survive inside a woman's body?

The birth of a healthy baby requires the joint efforts of men and women, which involves the combination of sperm and egg. We know that the vitality of sperm is limited, so how long can it survive in the female body?

The production time of a new sperm cell is about 64 to 72 days from start to finish. The average survival time of sperm in the male body is only a few weeks (in the female body it is even shorter, only 2 to 3 days). Add in the fact that up to 300 million sperm are ejaculated in each ejaculation, and the "sperm factory" in the male body is quite busy.

Generally speaking, the life span of sperm in a woman's vagina does not exceed 8 hours. After that, only a small number of sperm will escape and continue to move forward. Why is this? Because when a man ejaculates, the sperm in the semen can be protected by a large amount of fructose and enzymes that break down sugar in the semen.

When the sperm enters the uterine cavity, it leaves the semen. The living conditions at this time are far worse than when it is in the semen, so its lifespan is greatly shortened. Sperm of poor quality moves slowly and cannot reach the uterine cavity quickly, thus losing its vitality.

So, after the sperm enters the female body, how long can the sperm survive in the female body? Experts say: After the sperm passes through many checkpoints, only a few sperm can finally reach the fertilization site in the fallopian tube. However, as long as the sperm enters the fallopian tube, it has a strong fertilization ability.

Of course, only 1-2 sperms are lucky enough to combine with the egg, and the rest of the sperms die within 24-36 hours. Only the sperms stored in the crypts of the cervical mucosa can live for 2-6 days, but their fertilization ability is basically lost, because most sperms can only maintain fertilization ability for about 20 hours.

Although sperm injected into the female reproductive tract can survive for up to 4-5 days, the time with strong fertilization ability is only 1-2 days. That is to say, conception is only possible if women have sex within 1-2 days before or after ovulation.

Sperm residence 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 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 dies.

Sperm residence 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, at pH 7, there is a slight ability to penetrate, at pH 7.5, the ability to penetrate is normal, and at pH 8.2, 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 the cervical mucus by the hydrolysis of enzymes. Trypsin-based chymotrypsin and hyaluronidase can hydrolyze cervical mucus, reduce viscosity, and lose the formation of sticky threads, which is conducive to the passage of sperm. Under normal circumstances, the survival time of sperm in the cervix is: in the cervix, sperm can be found in the cervical mucus 15 minutes after intercourse; one hour later, sperm enters the internal opening; in the uterine cavity, sperm is found in the uterine cavity 1 hour after intercourse, after 6 hours, all are active sperm, 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 survive for a particularly long time.

Sperm residence time in the fallopian tube

In the fallopian tube, there are active sperm 14 hours after sexual intercourse, and sometimes there are still active sperm 35 days later. Generally, those that are 14 days old are the most active, and some enter the abdominal cavity. Those that move slowly are pushed back into the uterine cavity by the cilia.