How To Determine The Gestational Age

2024 Author: Rachel Wainwright | [email protected]. Last modified: 2023-12-15 07:39

How to determine the gestational age

In the first months of intrauterine life, the development of the embryo occurs at a rapid pace. Almost every week, the laying and development of internal and external organs and systems takes place. The future baby is proportionally increased in size and weight. As he grows, his needs for certain chemical elements change, and folic acid, iodine preparations and certain diets are prescribed for a pregnant woman. That is why it is necessary to know the exact date of pregnancy in order to manage a pregnancy. How to determine the gestational age?

Determining the duration of pregnancy by menstruation

Since menstruation stops with the onset of pregnancy, the date of the last discharge is the most common obstetrician argument. The obstetric period is calculated from the first day of the last menstrual period and is usually 14 days ahead of the actual pregnancy period, since ovulation occurs not at the beginning, but in the middle of the menstrual cycle. The method for determining the duration of pregnancy by monthly is used to calculate the date of birth. For this, the start date of the last cycle is taken, three months are subtracted from it, then one week is added. This date, in turn, is necessary to calculate the timing of maternity leave. However, in rare cases, after conception, spotting menstruation may occur, and this can seriously affect the result.

When calculating the gestational age, the moment of the first fetal movement, which occurs at 20 weeks in primiparous and at 18 weeks in the second and subsequent births, can also be taken into account. But this factor is very subjective, because some mothers do not immediately notice the movements, and some, on the contrary, take the work of the digestive system for them. Therefore, the first movement can be a clarifying factor in determining the duration of pregnancy, but not decisive.

How to determine the duration of pregnancy by the size of the uterus

Up to 8 weeks, an obstetrician-gynecologist can, by examining the vagina, determine the gestational age with an accuracy of a week. To do this, the doctor palpates and estimates the size of the uterus. At 4 weeks, it reaches the diameter of a chicken egg, at 8 weeks - a goose egg. After 8 weeks, the size of the uterus may differ from woman to woman at the same gestational age. Moreover, if the pregnancy is multiple, the uterus enlarges even more. However, for up to 8 weeks, the size of the uterus is a more reliable indicator than the previous ones.

How to determine the duration of pregnancy by ultrasound

Ultrasound examination in the first months of gestation allows you to determine the age of the embryo with an accuracy of one day, but only up to 8-12 weeks. After this period, the accuracy of the method decreases significantly, for example, at a period of 36-38 weeks, ultrasound can determine the gestational age only with an accuracy of 1-2 weeks. How to determine the duration of pregnancy by ultrasound in the first trimester? The fact is that ultrasound is an accurate method, but not absolutely perfect. When the embryo is barely 2-3 weeks old (which roughly coincides with the first days of the delay), the ultrasound machine can only see the ovum, and if you try to take a picture of the uterine cavity, you can barely see a small dot. However, at such an early stage, the apparatus does not always determine the presence of an embryo. It is much more likely to see the unborn child on an ultrasound scan and estimate the gestational age after 4 weeks of gestation. Although during this period, the size of the embryo is only 3-4 mm. What if you missed the first scheduled screening, and you do not know the exact date of conception? How to determine the duration of pregnancy by ultrasound in this case? In the second trimester, the main indicator is the size of the average inner diameter of the ovum, or the coccygeal-parietal size of the embryo. These data allow you to determine the gestational age with an accuracy of 6 days. In the third trimester, the size of the cerebellum is taken as the main indicator of fetal development. Do you know the exact date of conception? How to determine the duration of pregnancy by ultrasound in this case? In the second trimester, the main indicator is the size of the average inner diameter of the ovum, or the coccygeal-parietal size of the embryo. These data allow you to determine the gestational age with an accuracy of 6 days. In the third trimester, the size of the cerebellum is taken as the main indicator of fetal development. Do you know the exact date of conception? How to determine the duration of pregnancy by ultrasound in this case? In the second trimester, the main indicator is the size of the average inner diameter of the ovum, or the coccygeal-parietal size of the embryo. These data allow you to determine the gestational age with an accuracy of 6 days. In the third trimester, the size of the cerebellum is taken as the main indicator of fetal development.

How to determine the duration of pregnancy by hCG

HCG is an abbreviation for human chorionic gonadotropin. HCG is a hormone that begins to be produced after the embryo is implanted into the uterine wall. How to determine the duration of pregnancy by hCG? The production of the hormone begins 6-8 days after fertilization of the egg and increases over time. It is to the presence of hCG in the blood and urine that popular pharmacy pregnancy tests, both paper and electronic, react. The hormone hCG is essential to maintain a normal pregnancy. In the first weeks of gestation, its level can double every 2-3 days, this growth stops by the end of the second month of pregnancy, after which the indicator begins to gradually decrease. With multiple pregnancies, the hormone level increases in proportion to the number of fetuses, for example, with two fetuses, it doubles. Determining the duration of pregnancy by hCG will help when the ultrasound machine is not always able to see the fetus, but only if the embryo is not 5 weeks old.

Clearblue with gestational age

Modern tests for determining pregnancy allow you not only to find out if your cherished 9 months have started, but also to determine how long you are. And one of these tests is Clearblue with gestational age.

It looks like a regular digital test - the narrow end must be immersed in a container of urine for 20 seconds. If you have activated the test correctly, an hourglass icon will appear on the display. Now, within a few minutes, the test will show a plus in case of pregnancy and a minus in its absence. Under a positive result, after a few seconds, information about the period will appear - it can be 1-2 weeks, 2-3 weeks, or 3 weeks or more.

Clearblue with pregnancy detection is relevant as early as 4 days before the expected delay. Unlike strip tests, Clearblue provides a clear and unambiguous answer that will be visible on the screen within 24 hours.

Each of the methods given by us for determining the gestational age is effective at its stage. For example, in the very early stages, these are Clearblue and hCG tests. For a period of 5-8 weeks, this is an obstetric method for determining the size of the uterus. For a period of 8 weeks onwards, the most reliable method is ultrasound.

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