Ovulation is a sign of fertility in women. The basic conditions for ovulation are: the follicle matures, and there is a hormonal environment in the body that promotes the release of eggs, both of which are indispensable. Generally speaking, women only ovulate once a month. As we all know, having an egg released is a basic condition for conception. So when exactly does the egg come out? How old is it to be discharged? How does an egg feel when it is released?
The little follicles have grown!
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Ovulation process
After entering puberty, the pituitary gland begins to secrete gonadotropins, awakens the primitive follicles in the ovary to begin to develop, synthesizes estrogen, and the space around the oocytes is filled with fluid, containing a large amount of estrogen. The growing follicles gradually move towards the surface of the ovary, the walls of the follicles become thinner and thinner, and finally rupture, and the mature eggs are sucked into the fallopian tubes with the follicular fluid, a process called ovulation. Only one mature follicle is released every month, while the general follicle will have mature eggs in it at more than 18 mm in diameter.
Women of childbearing age generally ovulate once a month, which can be randomly discharged in turn by the left and right ovaries, or continuously by one side of the ovary. Ovulation is related to factors such as environment, mood, physical health, sex life, contraceptives, etc., and can occasionally be advanced or postponed, or may be two eggs at a time, sometimes even for several months without ovulation.
Figure 1: Ovulation process in the ovaries
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How big the egg is discharged
Follicles larger than 18 mm are mature follicles, and normal follicles should be between 18 and 25 mm in diameter. The diameter of the follicle ovulation is appropriate for each person, or varies from "month to month". Some are lined up to 15mm in diameter, while others are grown to 25mm. Follicle development is a continuous process, from primary follicles to mature follicles can be divided into 8 levels, the first 5 follicles may take 2 to 3 months to grow, from the 6th follicles to the 8th follicle is a total of about 10 days, which is exactly the follicle period in a menstrual cycle.
Figure 2: Hypoveal monitoring under ultrasound
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When the egg is released
As we all know, egg release is the basic condition for conception. However, many women are not quite sure when they are ovulating or conceiving. In fact, there are precursors to egg release. Before ovulation, due to the increase in estrogen in the body, increased cervical mucus secretion, the appearance of brushed transparent vaginal discharge, some patients have slight abdominal swelling and pain during ovulation, etc., after ovulation, under the action of progesterone, the basal body temperature will rise by about 0.3 to 0.5 degrees.
In general, a woman's ovulation day is about 14 days before her next menstrual period. To be on the safe side, we call the ovulation period 10 days before and 4 days after the ovulation date, along with the ovulation date. If the menstrual cycle is not normal, you can determine whether there is ovulation by measuring body temperature, cervical mucus, etc.
Figure 3: Menstrual cycle versus follicle cycle
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Why not ovulate?
Nonovulation is a type of ovulation disorder and is one of the main causes of female infertility, accounting for about 25 to 30%. Follicle development and ovulation are regulated by the hypothalamic-pituitary-ovarian gonadal axis, so abnormalities in any of the three layers of the gonadal axis can cause ovulation disorders.
If long-term non-ovulation, sex hormone metabolism disorders, endometrial hyperplasia without the anti-antagonistic effect of cyclical progesterone, can easily induce endometrial cancer.
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The list of egg failures is as follows
The hypothalamus does not ovulate
This is a key link in the gonadal axis, which stimulates the pituitary gland to secrete FSH and LH by releasing GnRH.
1. Organic lesions, such as craniopharyngioma, traumatic brain injury, central infection and congenital dysplasia.
2. Functional lesions:
Mental illness: excessive nervousness, depression, psychological problems
Weight: too light or too heavy more than the standard weight of 85% to 120%
Strenuous exercise: such as athletes and ballet dancers
Drugs: long-term use of chlorpromazine, contraceptives
Pituitary anovulation
1． Tumors: such as pituitary adenomas, mostly secrete prolactin, or growth hormone
2． Injuries: ischemia during childbirth (Sieghan syndrome), inflammation, radiation, surgery
3． Empty sella syndrome
Ovary anovulation
1． Congenital ovarian dysplasia: 45, XO; 47, XXX, etc
2． Gonadotropin (Gn) insensitivity syndrome: the ovaries do not respond to Gn, the etiology is unknown, and may be associated with autoimmune disorders or ovarian Gn receptor deficiency
3． Premature ovarian failure: < 40 years of age amenorrhea, FSH and LH>40U/L, E2<50pg/ml.
4． Polycystic Ovary Syndrome (PCOS)
5． Unruptured follicle luteinization syndrome (LUF)
If you have problems with ovulation, ask your reproductive endocrinologist to determine which level your problem is at through hormone measurements, ultrasound, cranial CT or MRI, and various irritation tests.
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