A premenstrual endometrial thickness of 15mm does not determine the time of menstruation; if menstruation is regular, the time of onset of menstruation can be inferred from the menstrual cycle. If menstruation is irregular, the approximate time of menstruation can be inferred from the date of ovulation in the current cycle. However, the endometrium is usually less than 15mm thick before menstruation, so it is important to consult a doctor to find out if there is any disease.
The onset of menstruation usually occurs about 14 days after ovulation. If menstruation is regular, the time of the next menstrual period can be determined by the menstrual cycle and the time of the last menstrual period; if menstruation is irregular, the date of ovulation in the current cycle can be used to infer the time of the next menstrual period. If the date of ovulation is uncertain, a sex hormone test can be performed and the physician can determine the approximate time of the onset of menstruation.
Because the onset of menstruation is essentially the shedding of the uterine lining, the endometrial lining is at its thickest during the cycle before menstruation, and is usually about 10mm thick. However, if the endometrium is 15mm thick, you need to consider whether there is pregnancy, endocrine abnormality, etc. It is recommended to consult a doctor in time, and under the guidance of the doctor, complete the relevant examinations to determine whether there is a disease.
The thickness of the endometrium varies with the changes in ovarian function during the menstrual cycle and cannot accurately predict the time of menstruation, which varies from person to person, so it is inaccurate to determine how soon menstruation will occur through the thickness of the endometrium.