As soon as a woman finds out that she will become a mother, first of all, the question arises of determining the duration of pregnancy. This is necessary for calculating the expected date of birth and for monitoring the condition of the expectant mother and child throughout the entire period of pregnancy. After all, all survey results are compared with certain standards.
Determine your pregnancy by the date of the start of your last period. The number of weeks that have passed since that day will be equal to the medical pregnancy period. The due date for this method is determined by adding 280 days or 40 weeks to the date of the start of the last menstrual period.
You can calculate the gestational age by the date of conception, or ovulation. Add two weeks to this date. The term of labor according to this method is calculated as follows: add 38 weeks to the date of ovulation, or subtract 3 months and 7 days.
Determination of the gestational age is carried out by the method of bimanual vaginal examination. The obstetrician-gynecologist, upon examination, determines the size of the uterus, each term corresponds to a certain size. By the 14th week of pregnancy, the fundus of the uterus is probed over the pubic symphysis. After 18 weeks, determine the height of the fundus of the uterus above the bosom using a tape measure. The number of centimeters corresponds to the gestational age in weeks.
The gestational age is determined by ultrasound examination. When carrying out this diagnostic method, the distance from the crown of the fetus to the sacrum is measured, as well as the coccygeal-parietal size. Then they compare the data with the standards, the sizes correspond to certain stages of pregnancy. The most accurate method is in the first trimester of pregnancy. In the future, the size of the fetus varies and depends on individual characteristics and on the nature of the course of pregnancy. According to the ultrasound data, the estimated weight of the fetus can also be calculated. Such information is essential for choosing a method of delivery and reducing the number of complications during labor.
The gestational age before the appearance of ultrasound was counted by the first fetal movement. Primiparous women began to feel the baby's movements from 19-20 weeks of pregnancy, and multiparous women - from 17-18. This method is currently not informative.
The gestational age for each method may differ slightly, therefore, it is finally calculated by summing all the data and obtaining an average value.