Normal range of mature follicle size

The follicle is an important component of the ovary, and whether the follicle is normal is closely related to whether the female fertility is normal. If the follicle is not mature or there is no follicle, then the woman is basically infertile. Of course, follicles are divided into two types: mature and immature. So, what is the size of a mature follicle? This will be introduced below!

1. What is a mature follicle?

Mature follicles are one of the structural components of the ovary. Every month, women release a mature egg, and this egg is generally considered mature if it is larger than 2.0mm.

The mature follicle cavity is large and the cumulus is obvious. The endometrial cells are close to the granulosa layer of the follicle and are separated from the granulosa layer cells by a basement membrane. The endometrial cells are polygonal, with clear cytoplasm and round nuclei. Many capillaries can be seen between the cells. The exometrial cells are located in the outermost layer, mostly spindle-shaped, and have no obvious boundary with the surrounding connective tissue.

2. Size of mature follicles

Every month, women will only release one mature egg, and this mature egg is generally considered a mature egg when it is larger than 20um. However, there are individual differences. Some people will release an egg when the follicle grows to 15um, while others will release an egg when it grows to 25um. The specific individual situation can be determined by a periodic B-ultrasound examination. Generally, mature follicles will be discharged within one to two days, and the discharged follicles can generally survive for 2 days.

3. Reasons why follicles do not ovulate

Luteinized unruptured follicle syndrome: This disease refers to the situation in which the follicle matures but does not rupture, the oocyte is not discharged but luteinized in situ, forming a corpus luteum and secreting progesterone, and a series of changes similar to the ovulation cycle occur in the body's effector organs. The main clinical features are regular menstrual cycles, similar ovulation performance but persistent infertility.

Use of ovulation-inducing drugs: Modern medicine's drug treatment for unruptured follicle-lutein syndrome is mainly the use of ovulation-inducing drugs. Improper use of ovulation-inducing drugs, inappropriate timing, or premature or delayed use may lead to unruptured follicle-lutein syndrome.

Central neuroendocrine regulation disorders: Common diseases in patients with anovulatory follicles are polycystic ovary syndrome, hyperprolactinemia, hyperandrogenemia and other endocrine diseases. Ovulation requires the formation of an LH peak. If the hypothalamus-pituitary-ovarian axis is disordered, the LH peak is too low, that is, LH secretion is insufficient, which will affect ovulation.

Local mechanical factors and local endocrine disorders: In patients with anovulatory follicles, the estrogen level in the follicles decreases, weakening the negative feedback on FSH. FSH remains at a high level after 2 days of increase and then slowly decreases after 4 to 5 days.