how many weeks pregnant am i​?The week of pregnancy can be calculated from the 1st day of the last menstrual period, and can also be determined by the hormones in the body, progesterone, and fetal developmental characteristics. There are various methods to calculate the number of days of pregnancy, including the method of calculating the last menstrual period, ultrasonography calculation, calculation of the day of ovulation, and estimation of symptoms and signs. It is necessary to choose the appropriate method according to the individual's specific situation and make comprehensive judgment and adjustment when necessary.

Last menstrual period calculation method

This is the most commonly used method. Starting from the first day of the last menstrual period, the entire pregnancy period is about 280 days, i.e. 40 weeks.

Ultrasound Calculation Method

In early pregnancy, usually 6-13 weeks, ultrasound is performed to estimate the week of pregnancy by measuring the size of the gestational sac, the length of the buds and other data. In the middle and late stages of pregnancy, the gestational week can be estimated based on the biparietal diameter of the fetus, femur length and other indicators, but its accuracy may decrease as the gestational week increases.

Calculation of Ovulation Day

It is more suitable for women with irregular menstrual cycles or those who conceive by monitoring ovulation. If the day of ovulation is clearly known, the number of days of pregnancy is usually the day of ovulation plus 14 days.

Estimation of Signs and Symptoms

Early pregnancy reactions, such as nausea, vomiting, breast tenderness, etc., usually start around 6 weeks of pregnancy and can be used to roughly estimate the number of days of pregnancy. As the weeks of pregnancy increase, the uterus will gradually increase in size, and the doctor can initially determine the week of pregnancy based on the size of the uterus through gynecological examination.

For women with long or short menstrual cycles, the last menstrual period calculation method may have some errors, which need to be corrected in conjunction with an ultrasound examination. There may be individual differences in the rate of fetal development, so ultrasound estimates of gestational week may also fluctuate by a few days.

During pregnancy, several ultrasound examinations may be performed. By comparing the results at different times, a more accurate assessment of the number of days of pregnancy and the development of the fetus can be made. To more accurately calculate the number of days of pregnancy and the expected date of delivery, doctors usually take into account a number of factors, including the last menstrual period, ultrasound, and symptoms.