How many sperm are there?
There are a lot of sperm in a man’s body. But how many? A fertile male usually churns out between 5 million to 250 million sperm cells per milliliter of ejaculate (the average human ejaculate is between 0.75 mL and 2.5 mL). Out of the millions, fewer than a hundred sperm cells actually arrive at the oocyte. And out of those, only one can fertilize the oocyte. The odds are against any individual sperm!
What is the sperm’s goal?
The goal of the sperm in semen is to swim through a woman’s cervix and uterus to end in the fallopian tube in search of an egg. This is a difficult process for the sperm. During this process, sperm cells face many obstacles, and with each obstacle, the sperm count goes down. Out of the half-million sperm that started out on the journey, relatively few actually reach the woman’s egg, if there even is one available at that time.
The sperm reaching the prize!
So what happens when the lucky sperm finally gets to meet the egg? Sparks fly! The magic of conception can happen any time in the week after sexual intercourse has taken place. Post ejaculation, the time it takes the sperm to reach the egg can take 1 – 12 hours, but sperm are capable of surviving more than six days in a woman’s body. Research has shown that visible zinc sparks are released along with calcium levels at the time of fertilization. This is why Zinc supplementation can improve, among other things, male fertility and the potential to conceive. This fertilization releases a flash of light, and according to scientists, the size of the zinc spark determines the egg’s ability to grow into a healthy embryo. When it comes to in vitro fertilization, doctors are able to evaluate and grade the fertilized eggs as they grow in the lab, but they aren’t necessarily able to determine if they will implant.
And after the sperm fertilizes the egg?
When the sperm finally reaches its goal, the egg changes so that no other sperm can get through the barrier. Once fertilized, the egg can stay in the fallopian tube for up to 3-4 days while it divides into multiple cells and continues dividing on its journey to the uterus. Implantation happens when the egg attaches to the uterine lining. If the fertilized egg fails to implant it will be swept away during the next menstrual cycle. Once implantation occurs, the uterine lining thickens while a layer of mucus will develop over the cervix to seal it until labor.