Sperm can live in water for different lengths of time, depending on the temperature and the fluid surrounding them. But if they are exposed to soap, chemicals or chlorine, they die.
Many people believe that it’s possible to get pregnant if there is semen in the vagina. In order to fertilize an egg, sperm needs to reach the fallopian tubes in the woman’s body within a few days before she ovulates.
Ejaculation
After a man’s testicles produce sperm, it can’t leave his body until he deliberately ejaculates. His penis contains coiled tubes that help move the sperm along, and he has specialized glands — called seminal vesicles and prostate gland — that make a whitish fluid called semen. This mixture contains sperm, as well as water, salts, cellular debris and the hormone testosterone. The semen exits the penis through the urethra, which is the tube that urine and semen both travel down when he gets a erection.
During sex, a man’s muscles around his penis tighten, and the fluids from the prostate and seminal vesicles mix with sperm to form semen. The acidity of this fluid decreases as it travels to the urethra, and a man’s ejaculatory ducts (which connect the epididymis to the urethra) open. The semen then travels through the urethra and bladder neck until the body’s natural desire to empty the bladder triggers another burst of semen production.
During this process, some sperm cells are lost, primarily because they don’t have enough energy to move through the body’s tissues to reach an egg. And if they make it into the female reproductive tract, they’re still facing a long journey. In order to fertilize an egg, a single sperm must be able to break through a layer of protein that protects the egg from other sperm. If more than one sperm reaches the egg, they’ll compete to deliver genetic material to the egg, which can lead to embryonic defects like Down syndrome.
Cervical mucus
Cervical mucus is a crucial part of the female reproductive system. It protects and cleans the cervix, and it helps guide good quality sperm up through the cervix into the fallopian tubes and towards the egg for fertilization. It also changes the vagina’s pH from acidic to sperm-friendly.
The texture and appearance of cervical mucus change throughout the menstrual cycle in response to hormonal changes. It usually starts off dry or pasty and moves to a creamier texture as ovulation approaches. The most fertile cervical mucus is described as looking and feeling like raw egg whites, and it’s slippery and stretchy.
Once inside the female body, sperm have to swim through a very narrow passageway (cervix) to reach the egg. This is an extremely challenging journey for sperm, and only a few make it all the way to the egg. The rest are either killed by the acidic fluids of the cervix, or they get lost in a process called flowback, where the sperm swim into dead-end channels within the walls of the cervix.
Women who practice fertility awareness methods use the feel and consistency of cervical mucus to determine if it is safe to have unprotected sex. Days when the mucus is cloudy and sticky, or feels like raw egg whites are unsafe days to have sex. After ovulation, the mucus usually dries up and becomes clear again.
Cervical crypts
Cervical mucus is one of the primary signs of fertility in women, and it plays a huge role in how we are able to conceive. It’s a hydrogel made of salts, proteins, fats and water that’s produced in pockets in the cervix (the opening to the uterus) throughout the menstrual cycle and during pregnancy. It changes in composition with sex hormone levels. Knowing how to track cervical mucus can give you incredible insight into your fertility, and can also help you determine when you’re ovulating.
The cervix is the lower portion of the uterus. It has an external part, called the ectocervix, and an internal part, called the endocervix. It is shaped like a 2 cm long cylinder and is positioned between the vagina and uterus. During most of the month, it prevents sperm from entering the uterus. But as ovulation approaches, it becomes thicker and wetter, and under the influence of a surge in estrogen, creates “swimming lanes” for sperm to swim through.
After intercourse, millions of sperm mix with seminal fluid and enter the cervix through the urethra. But because they are exposed to air, most die within a few minutes of being released. The few that survive enter the cervical mucus and continue swimming up toward the egg present in the fallopian tube. This process takes about 48 to 72 hours.
Uterus
The uterus, or womb, is the organ in female mammals (including humans) and some non-mammalian species that accommodates a fertilized egg and fetus until birth. The pear-shaped organ is located in the pelvis. It has glands in its lining that secrete uterine milk for embryonic nourishment. The uterus and its surrounding cervix play a key role in ovulation, conception, pregnancy, and childbirth.
After ejaculation, sperm live for up to five days inside the fluid in a woman’s reproductive tract. During this time, they compete in a race to the egg and fertilize it. Those that fail can become blocked by a layer of proteins around the egg called the zona. Those that do make it to the egg will usually be killed by the body’s immune cells.
But what happens to sperm that dies during the course of this process? Scientists have been studying this question for years. They have found that a significant number of dead sperm are eliminated from the uterus. This is due to the fact that many of them don’t turn in the right direction when they enter the uterus. Those that don’t head toward the oviduct are attacked by the immune system and absorbed into the uterus lining. The rest head into a twisty space at the junction of the uterus and oviduct called the uterotubal junction, where they are trapped by the mucus lining of that space.
