The miracle of pregnancy you should know: the probability of pregnancy

Understanding the mechanisms of fertility treatment is the first step! We'll introduce the basic knowledge of fertility treatment in an easy-to-understand way.

The miracle of pregnancy that you should know!

Do you know the probability of getting pregnant?
Many people still believe that if they want a baby, they'll be able to conceive immediately.
In fact, even for healthy young men and women, the probability of conceiving a child on a single attempt, even with proper timing, is said to be only about 30%.
Many of you might be surprised and think, "Is that all?"
Furthermore, as we age and experience stress,
The probability of getting pregnant decreases steadily.
Knowing that, receiving a new life is,
It could be described as an incredible "miracle" created by a man and a woman.
However, there's no need to worry about whether you'll be able to conceive.
By understanding the mechanics of pregnancy correctly and resolving any questions or concerns,
This should allow you to proceed with your fertility treatment more smoothly.
This section provides easy-to-understand information on basic knowledge about fertility treatment and pregnancy.
Understanding how pregnancy works is the first step in trying to conceive! Let's make sure you understand it well and use it to help you both get pregnant.


Let's learn about the process of pregnancy.

Ovulation

When menstruation begins, about 20 follicles appear in the ovaries. One of these follicles grows to about 20 mm in size in about two weeks and is released from the surface of the ovary as an "egg." This is called "ovulation." The most fertile time for sex is said to be the day before ovulation and on the day of ovulation.

ejaculation

Sperm ejaculated into the vagina during sex travel through the cervix, then into the uterus, and finally into the fallopian tubes, aiming for the egg.

Fertilization

Multiple sperm surround the egg once it reaches the zona pellucida. Then, only one sperm breaks through the zona pellucida and enters the egg, meeting it. This is "fertilization." At this moment, a barrier is formed around the egg, preventing other sperm from entering.

Implantation

The fertilized egg, or "fertilized egg," travels towards the uterus while undergoing repeated cell division. Once it reaches the uterus and reaches the blastocyst stage (5 to 7 days after ovulation), it implants itself in the uterine lining.

Pregnancy

Once the fertilized egg implants, pregnancy is established. The woman's body reacts immediately, stopping the next menstruation and ovulation. Furthermore, the body undergoes changes for the baby, such as thickening of the uterine lining and enlargement of the breasts in preparation for breastfeeding.


The structure of the uterus

During pregnancy, the uterus grows rapidly, expanding to approximately 30 cm in length and 25 cm in width. This transformation is remarkable: its size becomes six times larger, its weight 20 times heavier, and its volume 2000 to 2500 times larger! This is possible because the uterus is made of muscle, known as the myometrium. Of all the human organs, only the uterus can change so dramatically.

Main role of the uterus

1. Prepare to receive a fertilized egg once a month.

The lining of the uterus, known as the "endometrium," plays a major role in pregnancy and menstruation. The endometrium prepares itself every month to receive a fertilized egg. If implantation does not occur, the thickened endometrium naturally sheds, resulting in menstruation. If implantation is successful, pregnancy is established.

2. Raising a baby

Once a fertilized egg implants in the uterus, the woman's body reacts immediately, stopping the next menstruation and ovulation. The fertilized egg then continues to divide within the uterus, developing into a fetus.

As you can see, the uterus plays a vital role in pregnancy. Therefore, it's important to keep it warm as much as possible.


The structure of the male genitalia

Naturally, the structure and mechanism of the genitals are completely different between men and women. In the testes, male hormones work to produce sperm. In addition, fluids that form the basis of semen, released from the seminal vesicles and prostate gland, combine with this to form semen, which is then expelled during ejaculation. The passage through which semen exits is the same as the urethra, but its opening and closing are naturally regulated internally, so urine and semen do not mix. Men can only ejaculate when they are sexually aroused and their penis is erect. Just like the women's menstrual cycle, it's important to understand that the male genitalia are also susceptible to the effects of daily life stress.


The structure of sperm

Each sperm is so small it's invisible to the naked eye, with a total length of only about 50 microns, or 1/100th of a millimeter. Despite its tiny size, its tadpole-shaped head is packed with essential genetic information, including DNA and chromosomes. Furthermore, its tail acts like a fin, and sperm with a well-functioning tail can move forward with great force.
While many sperm are produced in the testes, not all of them are good sperm. Sometimes abnormal sperm are produced, but these are not capable of fertilization, so there is no need to worry.

☆Important points for men trying to conceive
The key is to "avoid accumulating too much sperm and to avoid abstinence."

The testes produce new sperm every day, and those that temporarily accumulate are released during ejaculation. If sperm accumulate for too long, the quality and motility of the sperm deteriorate. If you are hoping to conceive, it is important not to abstain for more than 5 days, and to ejaculate at least once a week to release sperm. Make it a habit to produce as fresh and active sperm as possible.
Thus, pregnancy occurs through a combination of many miraculous events that take place within the bodies of both men and women. With this in mind, it's important to maintain good physical condition to increase your chances of conception.

Supervising Physician: Dr. Isao Tsuji

Vice Director, IVF Osaka Clinic

Graduated from Kinki University School of Medicine. After working at Kinki University Hospital, Sakurai Hospital, and as a lecturer in the Department of Obstetrics and Gynecology at Kinki University School of Medicine, he assumed his current position.

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