1. What is a follicle? A follicle is located in the ovarian cortex (that is, on the surface of the ovary). A follicle is composed of an oocyte and its surrounding follicular granulosa cells. 2. Development and maturation of follicles There are generally only 400-500 follicles that can develop and ovulate during a woman’s lifetime. Only one or two dominant follicles in this group of follicles can fully develop and ovulate, while the rest of the follicles degenerate and disappear during the development process. According to the morphology, size, growth rate and histological characteristics of the follicles, the follicles can be divided into four stages: the primordial follicle, the antral follicle, the sinus follicle and the preovulatory follicle. From the first day of menstruation to the maturation of the follicle, it is called the follicular phase, which usually takes 10-14 days. Ovulation occurs about 14 days before the next menstrual period. 4. Luteal formation and degeneration After the oocyte is expelled, the fluid in the follicle also flows out to the lowest point of the human pelvis (Douglas fossa), i.e. the rectal sink of the uterus. After the oocyte is expelled, the remaining tissue forms the corpus luteum. Progesterone peaks on the 7th-8th day after ovulation, around the 22nd day of menstruation, at which point it can be monitored in the blood for elevated progesterone to determine if ovulation has occurred. After ovulation, if the egg does not unite with sperm in time to form a fertilized egg (the future child), the corpus luteum begins to degenerate 9-10 days after ovulation. The luteal phase from the day of ovulation to the onset of menstruation is the luteal phase, usually 14 days. After the luteal function declines, the menstrual period begins, at which time new follicles develop in the ovaries and a new cycle begins. The significance of follicle monitoring In the course of infertility treatment, we have to monitor the follicles continuously and repeatedly, and we have to start monitoring the follicles as soon as they develop. By monitoring the follicles, we can understand the size, morphology, growth rate and ovulation of the follicles, so that we can better guide the clinical use of medication and timing of intercourse to increase the chance of conception. When the follicles are just starting to develop slowly, we can monitor them once every 2-3 days, but at a later stage, they will grow faster and faster and need to be monitored daily. In the process of follicle monitoring, if the two diameter limits of the follicle are greater than or equal to 3mm, it is called a flat follicle, then you need to intervene with herbal medicine to make the follicle grow round, because the follicle is like a seed, to be full and round, so its diameter limit difference must be less than 3mm; if the monitored follicle does not grow, you need to use herbal medicine to help the follicle grow; if you monitor many follicles, it is not good because they If many follicles are monitored, it is not good because they will compete for nutrients and will not grow, so it is unrealistic to think that having many follicles will make you pregnant with multiples; it is also important to mention that a large follicle (about 18mm) on the 11th-12th day of menstruation is not a good thing, this follicle is likely to have ovulation disorder. Follicle monitoring should be continuous and should not be interrupted at will, otherwise it loses its clinical significance. Here, by the way, we monitor follicles in order to better guide intercourse, so when the follicles are not yet mature, we should not have intercourse first to nurture our strength so as to avoid the lack of follow-up. 6, Follicular Flavinization Some follicles mature but do not rupture, the follicle will continue to grow, grow to 30-40mm, then lose the ability to fertilize, the formation of flavinization. Follicular luteinization is often asymptomatic and has no abnormal signs. Luteinization has a menstrual period similar to the natural menstrual cycle (with ovulation) and a biphasic basal body temperature curve, and can only be detected during ultrasound monitoring of the follicles or laparoscopy. Clinical ultrasound reports often suggest: ovarian cysts. During our follicle monitoring, when the follicles grow to a certain size it is usually necessary to stimulate ovulation with herbs or acupuncture to allow the follicles to expel and avoid luteinization. Luteinization tends to occur in patients with polycystic ovaries. Clomiphene is commonly used clinically to promote follicle growth and help those patients who have difficulty with follicle growth. However, many patients have a misconception that there are only about 400-500 follicles in a woman’s ovaries that can mature, and that using clomiphene will reduce the number of follicles and accelerate ovarian aging, so they refuse to use the drug. In fact, these 400 follicles come from the 300,000-500,000 follicles in puberty, which means that each of the 300,000-500,000 follicles has the potential to grow into one of the 400-500 follicles, so there is no need to be nervous. It is like if you only have 400 RMB (400 follicles), of course you will be careful with every dollar you spend, fearing that if you spend more you will run out of money; but what you have is 400,000 RMB (400,000 follicles), which is much higher than 400 RMB, so spending a dollar or a tenner will not have much impact on your wealth. Therefore, infertility patients should not confuse the concept, but should actively cooperate with their doctors in the use of medication to improve their condition and achieve the purpose of treatment.