Some expectant mothers who are pregnant or in the early stages of pregnancy have such curiosity and doubts. Can B-ultrasound show how long they are pregnant? Can you tell exactly how many weeks or months you are pregnant?
What is a B-ultrasound?
First of all, from the principle analysis, the transmission mode of B-ultrasound is a kind of sound wave transmission, that is, ultrasonic transmission. Usually, the sound people hear is between 50 Hz and 10000Hz, and the sound waves above 20000Hz are inaudible, that is, ultrasonic waves. When applied to detection, it is harmless to human body. At present, it is widely used in detection.
The intensity of medical B ultrasound is the lowest. So far, no case of fetal malformation caused by B-ultrasound has been found, so it is also the safest detection method.
Let's give you a general idea of how many weeks of pregnancy B-ultrasound can show. For your reference, but everyone's figure is different and the standard is not fixed.
around
At this time, the fetus is only 0.2cm, and the pregnancy can't be seen by B-ultrasound.
Five weeks
At this time, the fetus is 0.4cm, and the fetal sac can be seen, but it is very small, accounting for less than 65,438+0/4 of the whole uterus, and it was first seen in the embryo.
Six weeks
The fetus is 0.85cm, and the fetal sac, embryo and heartbeat are clearly visible.
Seven weeks
The fetus is 1.33cm. At this time, the fetal sac accounts for 1/3 of the whole uterus, and the embryo and heartbeat are clearly visible.
Eight weeks
The fetus is 1.66cm. At this time, the fetal sac accounts for 1/2 of the whole uterus. The yolk sac can be seen, and the fetal shape and fetal movement can be clearly seen.
Nine weeks
At this time, the fetus is 2. 15cm, the fetal sac occupies the uterine cavity of the whole uterus, and the placenta can be seen, and the outline of the fetus is gradually clear.
Ten weeks
At this time, the fetus is 2.83cm, the fetal sac gradually disappears, the placenta presents a crescent shape, and the fetus moves freely in amniotic fluid.
Eleven weeks.
When the fetus is 3.62cm, the fetal sac disappears and the placenta is clearly visible.
Twelve weeks
At this time, the fetus is 4.58cm, and the reproductive organs are gradually developing. If the fetus is deformed, it can be found at this time. The skull of the head is clearly visible, and the biparietal diameter can be estimated. If there is abnormality, it can be diagnosed in time, and various organs of the body gradually develop.
Thirteen to forty weeks
You can refer to the following table for comparison.
Some pregnant women find that their B-ultrasound results are inconsistent with the month they should be in at that time, so the reasons for the deviation of fetal body shape are basically as follows:
1, pregnant woman's figure
Some pregnant mothers are smaller, so the fetus as a whole is smaller and lighter than other pregnant mothers. There is no need to apply the established formula or follow the doctor's advice to have a baby.
Step 2 Placenta
If the fetus is too big or too small, it is sometimes related to the development of the placenta. If the placenta functions well, the fetus will get enough nutrition and oxygen, and naturally develop well.
3. Umbilical artery blood vessels
If there are problems with the umbilical cord in the uterine cavity, such as knotting, single umbilical artery, expected congestion and hematoma, these phenomena will affect the normal blood supply of the umbilical cord, thus affecting the weight of the fetus.
4. Blood sugar
If the maternal blood sugar content is too high, the fetus will be too large. Pregnant women should strictly control the intake of sugar during pregnancy, otherwise the baby and pregnant mother may induce diabetes in the future, and pregnant women are also prone to the risk of gestational diabetes.
5. The number of fetuses
If a pregnant woman is pregnant with twins or multiple births, the weight of each fetus will naturally be small.
6. Living habits of pregnant women
If the living habits of pregnant women are unhealthy, staying up late, drinking and smoking will affect the normal development of the fetus.
Important note: As long as the pregnancy test is carried out regularly according to the doctor's advice, the test results are normal, and it is normal for the fetus estimated by B-ultrasound to be slightly larger or too small. Pregnant mothers must keep a happy mood and don't care too much.