What is the Luteal Phase? Women need to know this knowledge

Many women do not understand what the luteal phase is. In fact, it is very easy to understand. Women will ovulate before menstruation. The period from ovulation to menstruation is called the luteal phase. It is worth mentioning that the length of the luteal phase is different for each woman.

1. What is the luteal phase

What is the Luteal Phase? The luteal phase is the period from ovulation to the day before menstruation. The luteal phase is relatively constant in length, averaging 14 days in non-pregnant women and ending on the first day of menstruation.

After a woman ovulates, under the action of luteinizing hormone, the ovarian cells further divide, and the cytoplasm will have yellow pigment particles and fat droplets, which appear yellow to the naked eye, so we call this new endocrine gland the corpus luteum. The development and outcome of the corpus luteum depends on whether the egg released by the follicle is fertilized. If not, it will last for about 14 days and then degenerate, which is then manifested as menstruation in women. If the egg has been fertilized, the corpus luteum will last until the end of the third month of pregnancy before degenerating.

2. When is the luteal phase?

The luteal phase is the period from ovulation to the day before menstruation. The luteal phase generally lasts 14 days. If the menstrual cycle is 28 days, then the luteal phase is the 15th to 28th day of the menstrual cycle.

Hormonal regulation mechanisms of the luteal phase:

1. After a woman ovulates, both LH (luteinizing hormone) and FSH (follicle stimulating hormone) drop sharply. Under the action of a small amount of LH and FSH, the corpus luteum is formed and gradually matures. The corpus luteum mainly secretes progesterone and also secretes estradiol, which causes secretory changes in the endometrium.

2. On the 7th to 8th day after ovulation, progesterone reaches its peak and estrogen also reaches another peak. Due to the combined negative feedback of large amounts of progesterone, estrogen and inhibin A, the secretion of pituitary LH and FSH decreases accordingly, the corpus luteum begins to atrophy, the secretion of estrogen and progesterone decreases, the endometrium loses the support of sex hormones, exfoliates, and menstruation occurs.

3. The reduction of estrogen, progesterone and inhibin A relieves the negative feedback inhibition on the hypothalamus and pituitary gland, FSH secretion increases, follicles begin to develop, and the next menstrual cycle begins again.

3. Formation and degeneration of the corpus luteum:

1. After ovulation, the follicular fluid flows out, the pressure in the follicular cavity drops, the follicular wall collapses, and many wrinkles are formed. The granulosa cells and endometrial cells of the follicular wall invade inward and are surrounded by the follicular outer membrane of connective tissue to form a corpus luteum.

2. Under the action of the ovulation peak of LH (luteinizing hormone), the granulosa cells and theca cells of the follicle are further luteinized to form granulosa-lutein cells and theca-lutein cells respectively. Both types of corpus luteum cells contain carotene, and the amount of this pigment determines the depth of the color of the corpus luteum.