Standard chart of abdominal circumference and uterine height during pregnancy

Every pregnant woman has a standard fetal abdominal circumference during pregnancy. As the pregnancy time increases, the fetal abdominal circumference of the pregnant woman continues to increase. In the late pregnancy, the changes in the fetal abdominal circumference and uterine height will fluctuate slightly. Because of this, pregnant women will worry about whether the fetus will have abnormalities. So, what is the standard change of fetal abdominal circumference during pregnancy?

Changes in the standard of uterine height and fetal abdominal circumference during pregnancy

At 32 weeks of gestation, the average abdominal circumference of the fetus is 26.20 ± 2.33. Begin measuring the fetal abdominal circumference from the 16th week of pregnancy. Stand up, use the navel as a reference, and circle the abdomen horizontally. The measured value is the fetal abdominal circumference. In fact, the fetal abdominal circumference has a relatively stable standard. The measured fetal abdominal circumference value can be compared with the index value to know whether it is normal. However, the fetal abdominal circumference standard of the pregnant mother is only a general standard value. The height, weight and other conditions before pregnancy should also be taken into account, which is greatly affected by the body itself.

The average fetal abdominal circumference increases by 0.8 cm per week. It grows faster during weeks 20 to 24 of pregnancy. After 34 weeks of pregnancy, the rate of growth of the fetal abdominal circumference slows down. If the fetal abdominal circumference is measured accurately at 16 weeks of pregnancy, the average increase is 21 cm by full term. When the hormone levels do not increase according to the standard, it generally causes worry and confusion in pregnant women. In fact, the growth of the fetal abdominal circumference is not exactly the same for every pregnant woman.

1. Start measuring the fetal abdominal circumference from the 16th week of pregnancy. The method is: the expectant mother stands up, takes off her clothes, completely exposes her abdomen, takes the navel as the standard, and takes a tape measure around the abdomen horizontally. The measured value is the fetal abdominal circumference. The fetal abdominal circumference increases by an average of 0.8 cm per week. The growth rate is faster during the 20th to 24th week of pregnancy, increasing by 1.6 cm per week; during the 24th to 36th week of pregnancy, it increases by 0.8 cm per week; after 36 weeks of pregnancy, the growth rate of the fetal abdominal circumference slows down, increasing by 0.3 cm per week. Taking the abdominal circumference of the fetus at 16 weeks of pregnancy as the number, the average increase in abdominal circumference of a full-term fetus is 21 cm. When the fetus's abdominal circumference does not increase according to the standard value, expectant mothers will feel confused. In fact, the growth of the fetal abdominal circumference cannot be completely consistent. This is due to:

2. When preparing for pregnancy, each person's weight is different, and the fetus's abdominal circumference is also different. The increase in the fetal abdominal circumference after pregnancy is due to the growth of the fetus and uterus, as well as many other factors affecting the pregnant woman herself: some pregnant women gain weight rapidly after pregnancy, their abdominal fat thickens quickly, and their hip circumference and fetal abdominal circumference increase faster than others; some pregnant women have severe pregnancy reactions and eat less, so the fetal abdominal circumference does not increase significantly in the early stage. It is not until the reaction subsides and the fetal abdominal circumference begins to increase continuously after weight gain; some pregnant women have significant hypokalemia, which can also cause a significant increase in the fetal abdominal circumference.

3. The growth and development of the uterus and fetus cannot be judged solely by the increase in the fetal abdominal circumference. It should be combined with other tests for comprehensive analysis. Expectant mothers do not need to worry because the fetal abdominal circumference is a few standard values ​​different. At 12 weeks of pregnancy, the height of the fundus of the uterus is about 2 to 3 horizontal fingers above the ischial tuberosity, and by the fifth month of pregnancy it will be 1 horizontal finger below the navel. The expectant mother can feel the location of the fundus of the uterus by herself, and the uterine height is about 18 cm at this time.

4. From 16 to 36 weeks of pregnancy, the uterine height increases by 0.8 to 1.0 cm per week, with an average of 0.9 cm. On the 24th Sunday, it is 1 horizontal finger above the belly button, and on the 28th Sunday, it is 3 horizontal fingers above the belly button. At 31 weeks of pregnancy, the standard value of uterine height should be 25~31.5 cm, and the standard value of fetal abdominal circumference should be 84~95 cm. A low uterine height value often indicates that the baby's intrauterine language development is delayed or deformed; a high uterine height indicates multiple births, deformed fetuses, macrosomia, breech presentation, high floating head position of the fetus, polyhydramnios, placenta previa, etc.

Correspondence table of gestational weeks, uterine height and fetal abdominal circumference

In clinical medicine, the size of the fetus can be estimated based on the uterine height and the fetal abdominal circumference, and the number of weeks of pregnancy can be estimated based on the uterine height. There is no definite correspondence between the number of weeks of pregnancy and the fetal abdominal circumference, because the fetal abdominal circumference is determined by the weight of the pregnant woman.

12 weeks: 2-3 horizontal fingers above the ischial tuberosity

16 weeks: 5-7 horizontal fingers between the umbilicus and pubic area

20 weeks: 18cm (15.3-21.4) below the navel

24 weeks: 24cm (22-25.1cm) above the navel

28 weeks: 3 horizontal fingers above the navel 26 (22.4-29) cm

32 weeks: 29 cm (25.3-32.0) between the umbilicus and the hilus

36 weeks: 2 horizontal fingers below the xiphoid process 32 (29.8-34.5) cm

40 weeks: 33 cm from the navel

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Generally, during prenatal check-ups, it is necessary to analyze and judge the approximate weight of the fetus based on the height of the uterus and the abdominal circumference of the fetus to assess the condition of the pregnancy. However, the values ​​of uterine height and fetal abdominal circumference are only basic and not accurate. This precise value will be affected by various factors. So this correspondence table is not very accurate. Pregnant women should make some smart judgments based on their pregnancy status.