What is the dominant ovarian follicle?

We all know that in order to successfully conceive, the combination of high-quality eggs and sperm is the key, but many women do not understand what kind of follicles are dominant and can produce better eggs. So in response to these doubts, let’s analyze for you what kind of follicles are dominant follicles and what is the normal size of the follicles?

1. What kind of follicle is the dominant follicle?

The so-called dominant follicle in medicine is a follicle that is larger than 10mm and smaller than 18mm on ultrasound. In the first half of the menstrual cycle - the follicular phase, under the action of estrogen. Usually several follicles develop successively and grow gradually. Through B-ultrasound monitoring, we find that near ovulation, there is always one follicle with the largest head, and after it ruptures and ovulates, the other follicles are absorbed and disappear one after another. We call this follicle with the largest head and the most mature development the dominant follicle. If the normal menstruation is 30 days, the follicle that grows to more than 1.0 on the tenth day of menstruation can be considered the dominant follicle.

2. What is the normal size of follicles?

Normally, we cannot see the egg before ovulation because it is very small. Only when it develops into a follicle can we see it under a microscope. At that time, it is already very large. The 10th to 14th day before menstruation is called the ovulation period. A mature egg is generally larger than 20mm, and the smallest one is normal at more than 18mm. The growth from primary follicle to mature follicle can be divided into 8 levels. The first five levels are too small and take too long to grow, so they do not have much practical significance. The focus should be on the 6th level onwards. The diameter of the level 6 follicle is 5mm; after 5 days, it grows to 10mm and becomes the level 7 follicle; after another 5 days of development, it reaches the level 8 follicle with a diameter of 16mm. The 8th level follicles are mature follicles. Therefore, it takes a total of 10 days for the 6th level follicle to grow to the 8th level follicle, which is exactly the follicular phase in a menstrual cycle. Starting from 16mm, after another 2-3 days, it will develop into a 20mm follicle and the egg will be released.

3. Follicle size and whether follicle development is normal have a great impact

If the size of the follicle is not standard and does not reach the normal value, it will affect normal ovulation or the quality of the eggs discharged will be poor, affecting normal conception. The normal standard for follicle size is that the follicle is round or oval, with a diameter of 18-25mm. If it is lower or larger than the normal size, it will affect normal ovulation. Ultrasound monitoring shows that the largest follicle appears on the 10th to 16th day of menstruation. The follicle is 20mm in diameter, round in shape, with thin walls, protruding to one side of the ovary, and has good internal sound transmission. Ovulation usually occurs within 10 hours, and ovulation is more common on the 12th to 18th day of menstruation, and a few occur on the 20th to 30th day.