How to accurately calculate the pregnancy time?
Calculation method of last menstruation
In medicine, the pregnancy time is usually calculated from the first day of the last menstruation, and the whole pregnancy is ***280 days, that is, 10 months. The calculation method is simple: add 9 or subtract 3 to the month of the last menstruation, and add 7 to the date. For example, if your last period was July 2023 1, then your expected date of delivery is April 8, 2024.
Fetal movement calculation method
If your menstrual cycle is irregular, then the last menstrual calculation method may not be applicable. At this time, we can calculate it by fetal movement. Generally speaking, fetal movement mostly begins at 18-20 weeks of pregnancy. Therefore, the primipara can count 20 weeks from the fetal movement date, and the multipara is 22 weeks, so that the approximate pregnancy time can be obtained.
Calculation method of morning sickness
In addition to the above two methods, morning sickness can also be used as a reference for calculating pregnancy time. Most morning sickness occurs in the first trimester, about the sixth weekend of pregnancy. Push forward 42 days from the day of morning sickness, which is the time of your last menstruation. Then push back 34 weeks from this day, and you can get the whole pregnancy time.
physical examination
The most scientific method is to judge the time of pregnancy through medical examination. Doctors can calculate the gestational age by measuring the head-hip length, femur length and the diameter between the two bones of the fetal head by B-ultrasound, which can determine your pregnancy time more accurately. In addition, through the method of body temperature curve, taking the last day of the low temperature section of the basal body temperature curve as the ovulation day, and then counting 38 weeks (264-268 days) from this day, the accurate pregnancy time can also be obtained.