Why do some surrogate mothers fail to fertilize their eggs?
For surrogate mothers who want to get pregnant quickly, they are very eager to be the first to know the good news, but it takes time for the fertilized egg to implant, so how long is this time? If the fertilization fails, what causes it?
“How many days does it take for a fertilized egg to implant?
● During pregnancy preparation, the time for the fertilized egg to bed is the time for the pregnancy test. The fertilized egg bed means that they start to settle in the uterus, which takes 6 – 7 days.
It takes 6-7 days for the egg to settle in the uterus. Normally, the egg starts to lay on the uterus around day 6-7 after fertilization, but it is still too small to be seen on an ultrasound, and a small sac may not be visible on an ultrasound until about 20-30 days after it has laid.
Usually, there is slightly more implantation in the posterior wall of the uterine body than in the anterior wall, and more in the midline than in the lateral wall.
●The entire process of the fertilized egg moving through the fallopian tube towards the uterus is slow and the woman’s body does not feel anything.
The fertilized egg is pushed by peristalsis and cilia, and then moves gradually towards the uterine cavity. Usually, on the third day after fertilization, a solid mass of 16 cells called a mulberry embryo, or an early blastocyst, is formed.
● When the early blastocyst enters the uterine cavity on day 4 after fertilization and continues to divide and develop into the late blastocyst.
● On day 6-7 after egg fertilization, the late blastocyst is the process of invading the endometrium after the zona pellucida has disappeared and is called fertilized egg implantation.
“How many sperms are needed to fertilize an egg?
A normal man of childbearing age produces tens of millions to 200 million sperm in a single act, of which more than 60% are viable sperm.
These spermatozoa have to work hard to reach the fallopian tubes, and one spermatozoa will be able to fertilize the egg.
There are many obstacles in the way of the sperm meeting the egg, and if the number of sperm is not large enough, it is difficult to realize the goal of fertilization.
As it turns out, these hundreds of millions of sperm are the ultimate “barrier breakers” and the egg can only be fertilized by the remaining 10-20 sperm that meet in the fallopian tube.
“Why do some of them fail to fertilize after fertilization?
The process of fertilization is silent and there is no major change in the body. If the fertilized egg fails to implant, then you are not pregnant, and if you are not pregnant, you will have a normal cycle, and you will have a normal menstrual period. So, if you continue to have normal periods, it means that the last fertilization process has failed.
● Defects in the embryo itself
◆Most of the time, it is always the healthiest sperm that combines with the egg, but there are some special cases in which certain abnormal sperm will rush to combine with the egg first, or sometimes it is because the egg combines with one sperm and then there is a second sperm that also combines with the same egg, and the fertilized egg formed in this way is congenitally defective. Therefore, couples should check their chromosomes for abnormalities before preparing for pregnancy, so that a healthy fertilized egg can be successfully fertilized.
●Women with endocrine disorders
◆ Some women who have been married for many years and have a normal sex life but have no hope of getting pregnant are probably due to insufficient ovarian luteal function, insufficient progesterone secretion, and endometrial abnormality, which affects the implantation of the fertilized egg. Therefore, women who have been infertile for a long time should undergo hormone six tests.
Hormone 6 test is the most common way to test the endocrine function of men and women. By measuring the level of sex hormones, it can help to understand the diseases related to endocrine disorders in time. The result of sex hormone six test can reflect to a certain extent whether the female endocrine is disordered and whether the ovarian ovulation is normal or not.
Uterine factors of surrogate mother
◆Deformed uterine development, uterine submucous fibroid, endometrial polyp, uterine cavity adhesion, endometrial tuberculosis and so on affect the fertilization egg implantation.
◆ Therefore, if surrogate mother wants to carry a baby successfully, she can have relevant treatment through hysteroscopy. Hysteroscopy is able to directly visualize intrauterine lesions and can quickly and accurately diagnose most intrauterine diseases. The cervical canal and uterine cavity and bilateral fallopian tube openings can be examined through hysteroscopy to find out the causes of interference with the fertilization egg’s implantation, and related uterine surgeries can also be carried out through hysteroscopy in order to minimize physical damage and psychological trauma to the pregnant woman.
●Immune factors
◆ For women, male sperm and sperm plasma are, obviously, a foreign substance. However, under normal circumstances, women do not produce anti-sperm antibodies. Only under certain circumstances, for example, because of inflammation and injury in the female reproductive tract, antibodies are produced in the female serum and cervical mucus.
Only under certain circumstances, such as inflammation or damage to the female reproductive tract, antibodies are produced in the female serum and cervical mucus. ◆ At this time, macrophages in the female reproductive tract, especially in the uterus, will cause an immune response to “self-defense”, which can make spermatozoa, which have penetrated the cervix, become inactive, coagulate or die.
Two types of immunization affect conception
◆Homoimmunity: Sperm, seminal plasma or fertilized egg are antigenic substances, which are absorbed by the epithelium of the vagina and uterus, and then produce antibody substances through immune reaction, so that sperm and egg can not be combined or fertilized egg can not be implanted.
◆Autoimmunity: It is believed that autoantibodies to zona pellucida exist in the serum of infertile women, and after reacting with the zona pellucida, they can prevent sperm from penetrating the egg, thus preventing fertilization.
Excessive mental tension
◆We often see some women who have not conceived for a long time. The longer the time, the more nervous they are, but the more they can’t conceive. In fact, among the many factors that cause infertility, mental and psychological factors are also an important reason. Women’s reproductive endocrine system is influenced and regulated by the cerebral cortex, if long-term mental tension, anxiety, etc., will disrupt the endocrine system and even inhibit the function of the ovaries, the natural pregnancy may cause ovulation early, delayed, or no ovulation, the IVF process will greatly reduce the chances of conception.
★Questions
Will coitus affect the fertilization of the egg?
No. Normal exercise and activities, including having sex, will not affect the fertilization of a fertilized egg. Fertilization occurs within 12 hours after ovulation and the whole process takes about 24 hours. Sperm is very active and generally has the ability to fertilize within 72 hours, while the egg is generally not fertilized after 24 hours, and the ability to fertilize within 12 hours is strong. Normal coitus does not usually have much effect on pregnancy.
Does exercise affect the implantation of fertilized egg?
◆Normal exercise has no effect, but strenuous exercise may have some effect on the fertilization of the egg. After intercourse, the fertilized egg enters the uterus first, and it takes 2 to 3 days for the egg to implant. If you exercise at this time, it will make the egg unstable, which will affect the implantation of the egg.