Only a very small fraction of ejaculated sperm actually make it all the way to the egg. Around 300 million sperm are typically released during sex, but only about 200 sperm will reach the egg. This is still a pretty big number since we only need one sperm to fertilize an egg.
-For the nearly 5,000 sperm that make it into the utero-tubal junction, around 1,000 of these reach the inside of the Fallopian tube. -For the 1,000 sperm entering the tube, only around 200 actually reach the egg. -In the end, only 1 lucky sperm out of this group of 200 actually penetrates and fertilizes the egg!
It takes about 24 hours for a sperm cell to fertilize an egg. When the sperm penetrates the egg, the surface of the egg changes so that no other sperm can enter. At the moment of fertilization, the baby's genetic makeup is complete, including whether it's a boy or girl.
Ovulation usually occurs about two weeks after your menstrual period and lasts for two or three days. This means you can sometimes determine when you conceived based on your ovulation cycles — simply determine when your last menstrual period was and add approximately two weeks.
Problems with fertilization
A blockage in the male or female reproductive tract can prevent fertilization. Or sperm may be unable to swim through the cervical mucus. And even if sperm do reach an egg, they may not be able to penetrate the egg's covering.
The first obstacle is the cervix, a complex labyrinth that prevents many sperm from eventually entering. Those who finally succeed, have to go through a "hostile" uterus and be lead to a narrow entrance, the fallopian tube. Those which finally enter the tube - very few in number - eventually meet the egg.
Normally, only a single one-celled sperm cell is allowed to fertilize one egg cell, resulting in the development of an embryo. After the first sperm breaks through a layer of proteins around the egg, this layer blocks more sperm from getting through.
Researchers from Stockholm University and the Manchester University NHS Foundation Trust found that the egg effectively chooses the sperm it wants, and rejects the others. "Human eggs release chemicals called chemoattractants that attract sperm to unfertilised eggs.
Is It Hard To Get Pregnant? Yes, getting pregnant can be hard, both physically and emotionally! Your fertile window is a small amount of time each month so it may take some time for conception to occur. (For reference, a healthy woman in her 30s only has a 20% chance of getting pregnant during each menstrual cycle.)
Only a very small fraction of ejaculated sperm actually make it all the way to the egg. Around 300 million sperm are typically released during sex, but only about 200 sperm will reach the egg.
IUI works by putting sperm cells directly into your uterus around the time you're ovulating, helping the sperm get closer to your egg. This cuts down on the time and distance sperm has to travel, making it easier to fertilize your egg.
Summary: Sperm in the first fraction of ejaculate are more numerous, move more and present better quality DNA than those lagging behind.
It appears some sperm fails to 'communicate' with the female reproductive tract and while a man can appear to be fertile, his semen can be rejected by a woman if it's not compatible with her. This is more likely to happen if a woman has not previously been exposed to his sperm over a period of time.
You won't feel when an egg gets fertilized. You also won't feel pregnant after two or three days. But some women can feel implantation, the process in which the fertilized egg travels down the fallopian tube and buries itself deep within the wall of the uterus.
Peak and Decline
Researchers found that semen quantity peaked between the ages of 30 and 35. (Could this be nature's way of making sure a couple conceives before female fertility starts to decline at age 35?) On the other end of the spectrum, overall semen quantity was found to be lowest after age 55.
For healthy semen samples collected between 5:00am and 7:30am were found to exhibit a statistically higher sperm concentration, total sperm count and a higher percentage of normally shaped sperm, compared to samples produced later in the day.
According to infertility research, the likelihood of getting pregnant in the first month is around 30% . For people without fertility issues, the approximate chances of conception are: 75% after 6 months. 90% after a year.
30% of couples trying to conceive did so in the first month. 75% of couples conceived within 6 months. 90% of couples conceived within 1 year. 95% of couples conceived within 2 years.
The highest pregnancy rates occur in couples who have sex every day or every other day. Have sex near the time of ovulation. If having sex every day isn't possible — or enjoyable — have sex every 2 to 3 days a week starting soon after the end of your period.
Infertility is a condition where you cannot get pregnant after one year of trying to conceive. In women, cause of infertility can include endometriosis, uterine fibroids and thyroid disease. Men with fertility problems may have a low sperm count or low testosterone. The risk of infertility increases as you age.
Taking into account how long sperm survive and the time it takes for fertilization and implantation, you can be pregnant as soon as seven days after you had sex or as long as 15 days.