correct determination of gestational age Scientists estimate that only 10% of infantsare born just in time. However, it is very important to know the timing of pregnancy. Firstly, you can psychologically tune in to birth and prepare in advance things that are necessary for the hospital. Secondly, doctors will determine whether the baby is premature or you are replacing the fetus. How to count the duration of pregnancy, gynecologists know. Based on these data, they choose the tactics of managing pregnancy and childbirth. Doctors conditionally distinguish 3 parts of the gestation period:

  • I trimester - from 1 to 13 weeks,
  • II trimester - from 14 to 26 weeks,
  • III trimester - from 27 to 40 weeks.

At each trimester obstetricians prescribe the necessary tests, screenings, examinations, ultrasound, identify the likelihood of possible pathologies. There are the following ways how to count the gestation period:

  • on the last monthly,
  • on the day of ovulation,
  • examination at the gynecologist,
  • Ultrasound,
  • on the movements of the child.

determination of the duration of pregnancy by uzi

Calculation of the period for monthly and ovulation

Find out how many weeks of pregnancy you candifferent methods. Among gynecologists, the term "estimated date of delivery" was adopted. The number and month are calculated by adding to the date of the last menstruation 280 days, or 40 weeks, or 10 menstrual cycles (corresponding to 9 calendar months). The gynecologist believes that conception occurred 14 days after the onset of menstruation. The accepted unit of measure is the weeks of pregnancy. A special formula has been derived for scientists of Negele, how to count the duration of pregnancy. The first day of the last menstruation + 7 days - 3 months. For example, September 10 + 7 days - 3 months = June 17. If the doctor starts counting the weeks of pregnancy from the last menstruation, when conception has not yet occurred, this is called a midwifery period. It may differ from the diagnosis of ultrasound for an average of 2 weeks, because ultrasound determines the period from conception. According to the second method, gynecologists count from the date of ovulation. Some women are very sensitive to their body and can feel the day of ovulation. With a regular menstrual cycle, 28 weeks to the day of ovulation, 38 weeks are added. But this method is rarely used, because a mature egg leaves the ovary in the fallopian tube on the 11-17th day of the cycle. Determine the ovulation will be able to just a special test. And of course, on this day it is necessary that the partners be close. In addition, conception may not coincide with ovulation, since spermatozoa can live in the body of a woman up to 5 days. A fertilization should occur within a day, until the egg is viable. determination of gestation after gynecological examination

Gynecological examination and ultrasound

Gynecologists can calculate the gestational age forPhysiological changes that occur in the body of a woman after conception. This process is called palpation. Having made a vaginal examination, the obstetrician is able to reveal the duration of pregnancy by weeks. After conception of the baby, the uterus begins to grow and rises a little above the pubic bone. With the help of a tachometer and a centimeter tape the doctor measures the size of the uterus, the centimeters obtained correspond to the period of pregnancy. Measurements of the height of the uterine fundus also indicate specific weeks. The exact length of pregnancy from the day of conception shows ultrasound in terms of the growth and weight of the child. During the ultrasound, the doctor records the gestational age of the fetus. And, to correctly count the weeks, ultrasound should be carried out at an early date, that is, at 8-12 weeks. During the second trimester the child develops individually and small deviations from the norm are possible. During ultrasound, doctors make measurements of the head, chest, abdomen, hips of the fetus, record the degree of development of its organs. And then check on the table and set how many weeks it corresponds to the developing fetus.

Calculate delivery according to the first movements

Calculate the estimated date of birth bythe first movements of the baby. At the first pregnancy, they appear in 19-20 weeks, with the following 2 weeks earlier. A gynecologist warns the pregnant woman beforehand so that she will remember from when the child began to actively stir daily. This day is entered in the pregnancy card of a pregnant woman or a mother's passport. To this date, add 20 weeks for the primipara and 18 weeks for the moles. However, on this principle, an exact obstetric term can not be determined, since full women feel jerking later than skinny.

Maternity leave

Calculate the duration of pregnancy is extremely important forworking women, because at 30 weeks pregnant women are sent on maternity leave. A gynecologist needs to prioritize laboratory tests and prepare documents. These include a certificate of registration in the early stages of pregnancy, a sick leave sheet and birth certificate. With these securities you apply to the accounting department, on their basis pregnant women are entitled to social cash payments and leave. Remember that the gestation period lasts from 38 to 42 weeks, it is very difficult even for a gynecologist to understand what day the conception occurred. The development of the child and the duration of the menstrual cycle occurs in each woman individually. The date of delivery, as determined by the gynecologists, can be shifted and represents only the intended day. you will certainly feel when this joyful event will happen.