How long does it take for sperm and egg to combine?

Everyone knows that if a woman wants to get pregnant successfully, the sperm must successfully combine with the egg. Men produce a lot of sperm, and the number of sperm is so large that it is unbelievable for many people. In comparison, the number of female eggs is very small. For example, a woman will only produce one mature egg every month. The mature egg and sperm must successfully combine to form a fertilized egg. This is a necessary condition for pregnancy. So how long does it take for the sperm and egg to combine?

How long does it take for sperm and egg to combine?

It takes about 24 hours for sperm and egg to combine.

During intercourse, a man discharges about 200 to 400 million sperm each time; however, most of the sperm are discharged from the vagina along with the semen. Because the cervical mucus is alkaline, it is conducive to sperm activity. A small number of sperm rely on the swinging of their tails to move forward and quickly swim into the cervical canal.

Sperm releases protein-lytic enzymes to dissolve cervical mucus; uterine contractions and fallopian tube peristalsis caused by sexual intercourse accelerate the movement of sperm; the peristalsis of the fallopian tube muscle layer, the swinging of mucosal cilia and the flow of fallopian tube fluid secreted by mucus cells lead to the movement of sperm from the uterine cavity to the ampulla of the fallopian tube.

At the final destination - the ampulla of the fallopian tube, it waits there to combine with the egg. It takes sperm only a few minutes to reach the fallopian tube from the vagina at the fastest, 4 to 6 hours at the latest, and usually 1 to 1.5 hours.

As sperms move forward, they are blocked by cervical mucus and swallowed by white blood cells in the uterine cavity. In the end, only dozens to one or two hundred sperms reach the fallopian tubes.

Before sperm can fertilize the egg, it must be incubated in the female reproductive cavity for a period of time and undergo morphological, physiological, and biochemical changes before it becomes capable of fertilization. This process is called sperm capacitation.

After entering the woman's vagina, the sperm immediately begin a long swim from the vagina to the entrance of the uterus. There, the mother secretes a sticky liquid that forms a net. When the egg flies out, the net is open, allowing the sperm to pass through easily. This net acts as a booster, helping the sperm to continue swimming upward.

Except for about 24 hours after ovulation, the net is closed at all other times, preventing sperm from entering the uterus. The number of sperm that successfully passes the "level" is about one thousandth during ejaculation.

The egg has the strongest fertilization ability within 15 to 18 hours after being released from the ovary, and can maintain its fertilization ability for about 30 hours. The fertilized egg undergoes cell division 24 hours after fertilization. The fertilized egg absorbs nutrients and oxygen from the fluid secreted by the fallopian tube and continues to undergo cell division.

At the same time, through the peristalsis of the fallopian tube, the fertilized egg gradually moves toward the uterine cavity and reaches the uterine cavity after 3 to 4 days.