What does last menstruation mean? Explanation of last menstruation.

1, the last menstruation refers to knowing the specific date of the last menstruation before pregnancy.

2. For example, Anonymous learned that she was pregnant on October 20th, 65438/kloc-0. She remembers that the date of her last menstruation was 15 September (the date of the first day of menstruation), and this "15 September" was her "last menstruation".

3, the expected date of birth, that is, the expected date of delivery of pregnant women. Because it is difficult to accurately judge the pregnancy time of pregnant women, it is medically stipulated that the expected date of delivery is calculated from the first day of the last menstruation and pushed back by about 280 days. That is to say, 40 weeks of pregnancy is equivalent to 10 months. The specific calculation method of the expected date of delivery of the last menstruation is: adding 9 or subtracting 3 in the month of the last menstruation is the expected date of delivery; Days plus 7 is the estimated delivery date.