During Miss Zhou’s pregnancy, the greeting my friends saw most of me was “When will I be born?” I believe many mothers have the same experience as me. When will this [be born? ], in fact is the expected date of delivery. At first, this really asked Miss Zhou, who has always boasted of rich medical knowledge. Knowledge about pregnancy and childbirth does have such a characteristic-when you or the person beside you are not pregnant, this knowledge is important and has nothing to do with you. No matter how profound a person is, he will not be idle enough to understand the knowledge of pregnancy and childbirth. However, once you or your wife are pregnant, it is like stepping into a completely new world. In normal days, the knowledge of pregnancy and childbirth [who loves to know who knows] has become something that must be understood and cannot be learned completely! How do you calculate the expected date of delivery? I still remember that I tested positive with pregnancy test paper. When I went to the hospital for the first time, the doctor asked several questions at the beginning: [was the last menstruation in what? How many days is the menstrual cycle at ordinary times? Is it regular? [Why do you ask these questions? Only then did I know that, The original expected date of delivery and gestational age, It is calculated from the first day of the last menstruation before pregnancy. Because the specific date of fertilization is too difficult to calculate, Ovulation dates are often uncertain due to large individual differences, Therefore, the first day of the last menstruation is taken as the starting point of the whole pregnancy. The calculation of the expected date of delivery is also based on the time of the last menstruation and the normal menstrual cycle: Minus 3 or add 9 to the number of months of the last menstruation, Add 7 to the number of dates, We can figure out the due date. Of course, This is calculated according to the normal menstrual cycle of 28 days. For girls with irregular menstruation, If there is often a difference of 3 or 5 days between the front and back, There is no need to change the due date, Because it is a range in itself. But if the menstrual cycle is regular, And each menstruation basically exceeds 35 days, so we must consider the corresponding delay in the calculation of the expected date of delivery. Sounds very abstract, let’s take an example: Zhou girl’s last menstruation time is June 23, 2014. If menstruation is regular, then the first day of the last menstruation on June 23 is 6-3 = 3, 23 + 7 = 30, and the expected date of delivery is March 30 of the following year. How to calculate irregular menstruation? Unfortunately, Miss Zhou’s menstruation is extremely irregular, Sometimes it takes 20 days, Sometimes it only comes once every 2 or 3 months, Sometimes it takes six months to patronize, And the time of each visit is uncertain, Sometimes it takes two or three days, Sometimes it takes 10 days and a half months to end. Even the [general] rules required by the doctor are not available. The doctor was also shocked by my [exotic] menstrual history. Fortunately, Miss Zhou usually has the habit of recording basal body temperature. If you don’t know basal body temperature yet, You can click to read the basal body temperature, Neglected magic weapon for pregnancy preparation. Judging from the thermometer, July 12 is the last day of low temperature, and the body temperature suddenly jumped by 0.5 ℃ in the early morning of July 13. This shows that ovulation is likely to occur on July 12. More coincidentally, that night, Miss Zhou and Dr. Tian did [homework], basically confirming that the ovulation day is July 12. Knowing the ovulation day, is it for what? Pushing the ovulation day forward for 14 days is theoretically the first day of the last menstruation, which is about June 28. According to this calculation, the expected date of delivery can be calculated: 6-3 = 3, 28 + 7 = 35 = 30 + 5-that is, April 5, 2015. Oda was really born on this day. [However, if I don’t even record the basal body temperature, wouldn’t it be miserable? ] Miss Zhou just likes to think much. Background Gao Hui, a doctor of obstetrics and gynecology in Tiantan Hospital, said, Like my menstruation is very irregular, and the number of days of each period is much different, then the expected date of delivery cannot be calculated according to the time of the last menstruation. Developed modern medicine also provides other ways to calculate the gestational weeks: do a B-ultrasound, and then calculate according to the biparietal diameter and femoral length of the fetus. According to the height of the uterine fundus to calculate; According to the date of pregnancy vomiting, the date of fetal movement, etc., can be calculated. When you can’t handle it yourself, listen to the doctor’s calculation, that’s right. The expected date of delivery is just a calculation-this is the most common key word when calculating the gestational week and the expected date of delivery. Even medicine has entered the era of [precision medicine], why should gestational week be calculated? Calculations mean that there are some inaccuracies. Will inaccuracies not affect subsequent inspections and final production? Dr. Tian said that the expected date of delivery is not a very accurate concept. Medically speaking, it is normal to give birth 3 weeks earlier or 2 weeks later than the expected date of delivery. [It is normal to give birth to babies between 37 and 42 weeks. Only 5% of babies will “step on the spot” on the expected date of delivery. However, Dr. Tian, who expressed indifference to the expected date of delivery, did not expect that his baby would become the 5% of the expected date of delivery. However, why is the whole gestational week 280 days? Why do most babies [start] one day between 37 and 42 weeks? Doctors say that modern science cannot explain the problem. But evolutionary scholars suspect that long ago, there may have been a huge difference in the length of pregnancy between different [people]. Without the intervention of advanced modern medicine, too long a pregnancy may have caused the baby’s head to be too big to pass through the birth canal smoothly. Too short a pregnancy may cause the baby to develop incompletely, Can’t sustain life after birth. Only babies between 37 and 42 weeks of pregnancy, Neither mother nor child will die because the head is too big to be born, Nor will it be impossible to survive because it is not fully developed… So, After long-term natural selection, The last pregnancy is about 280 days. These genes, Stay. Of course, This is only a conjecture. The question of the expected date of delivery also precisely illustrates the limitations of modern medicine. In the matter of giving birth, There are too many instincts, too many unexplained and too many unpredictable. In ancient times, it was said that giving birth to a child was a “death pass”. Even with modern medicine, childbirth is not a thing without danger. To correctly understand this matter, one should not blame the doctor for any problems. Second, cherish the woman who is willing to give birth to your baby, because she is really risking her life to give birth to the crystallization of your love!