How to calculate the time of pregnancy

During the prenatal check-up, the doctor will tell us the month and size of the fetus, as well as other developmental conditions. At this point, all prospective parents must be curious about the optimal algorithm for fetal size and how to calculate the number of days of pregnancy. The number of days of pregnancy is just a predetermined time. About half of pregnant women do not give birth on the due day. It is generally normal to give birth 3 weeks before or half a month after the due date. In fact, there are many ways to calculate the number of days of pregnancy, and pregnant mothers can calculate it independently according to their own conditions.

How to calculate the number of days of pregnancy

1. Calculate based on the expected date of delivery:

Add 9 or subtract 3 from the expected date of delivery to get the number of months of delivery. Add 7 to the number of days to get the due date. For example: Ms. Chen's due date is March 13, 2008, and her due date is approximately December 20, 2008. Ms. Chen's due date is May 28, 2008, and her due date is approximately March 5, 2009. You can also calculate backwards from the first day of the due date to the 280th day, which is the due date.

2. Calculate based on the baby's fetal movement date:

If you can't remember your due date, you can calculate it based on the baby's fetal movement time. Generally, fetal movement begins between 18 and 20 weeks of pregnancy. The calculation method is: first birth is the day the baby moves plus 20 weeks. For multiparous women, the time is the day of fetal movement plus 22 weeks.

3. Calculated based on the basic body temperature curve:

The last day of the ultra-low temperature segment of the basal body temperature curve is taken as the ovulation period, and 264-268 days are counted backward from the ovulation period, or 38 weeks are added.

4. Calculation based on B-ultrasound examination:

When doctors do B-ultrasound, they can measure the biparietal diameter of the fetal head, the brachiocephalic diameter and the length of the femoral head to estimate the gestational age and calculate the date of delivery (this method is mostly used by doctors for B-ultrasound examination and diagnosis).

5. Calculate from the time when morning sickness starts:

Morning sickness usually occurs on the 6th week of pregnancy, which is 42 days after the expected date of delivery, and then counting backwards to 280 days is the due date.

How to calculate ovulation period

For women with regular menstruation, the ovulation period is generally 14 days before the next menstruation. The ovulation period is calculated by subtracting 14 from the menstrual cycle. For women with menstrual disorders, in order to calculate the ovulation period more accurately, they must cooperate with the ovulation test paper method, ovulation temperature measurement method and secretion observation.

1. Aquino Law

The Aquino method is also called the formula method, which means that the ovulation period is about 14 days forward from the last day of the menstrual cycle (that is, the first day of the next menstrual period). If the day of the next menarche is day N, then the ovulation period this time is day N-14.

2. Ovulation test paper method

The progesterone in women's urine is converted into growth hormone (LH), which will reach a peak value within 24-48 hours before ovulation. The use of ovulation test strips can more accurately detect the highest level of LH. After starting the test, you should perform the test regularly every day. When a color close to the peak value appears, you should test it every 12 hours until the highest LH value is detected.

3. Methods for measuring body temperature during ovulation

Continuously measure the ovulation body temperature accurately for six to twelve months and record it in various aspects. The ovulation body temperature will rise by 0.3-0.5℃ after ovulation. Women who are preparing for pregnancy can buy a digital thermometer, set it below 35 degrees Celsius before going to bed every day, and measure their temperature immediately after waking up every morning (after 6-8 hours of sleep) without doing any exercise.

4. Observation of secretions

During a physiological cycle, the characteristics of secretions also change regularly. Normally, the discharge is drier, thicker, and less in quantity. During ovulation, the secretions will become clearer and more transparent, like egg white, with a high degree of metallic brushing. This is because during ovulation, higher concentrations of estrogen are produced, which act on the columnar squamous epithelial cells at the cervical opening, causing them to secrete a large amount of secretions.