Normal range of amniotic fluid index at 34 weeks

For a woman, pregnancy is something that she must experience in her entire life, and every pregnant female friend will feel the mixed feelings of happiness and joy of having a baby in her belly. With the development of the times, women's pregnancy has become a matter that the whole family attaches great importance to. What pregnant women are more concerned about may be the normal range of the amniotic fluid index at 34 weeks. For this reason, experts have specially made the following detailed explanation for every expectant mother.

During a normal pregnancy, the amount of amniotic fluid increases with the gestational age and begins to gradually decrease in the last 2 to 4 weeks. At full-term pregnancy, the amount of amniotic fluid is about 1000ml (800-1200ml). If the amount of amniotic fluid exceeds 2000ml at any time during pregnancy, it is called polyhydramnios. The maximum can reach 200005a8ml. For most pregnant women, the increase in amniotic fluid is slow and takes a long time, which is called chronic polyhydramnios. For a few pregnant women, the increase in amniotic fluid is rapid within a few days, which is called acute polyhydramnios. The incidence of polyhydramnios is reported in the literature to be 0.5% to 1%. In pregnant women with diabetes, the incidence can reach 20%. When there is polyhydramnios, the appearance and properties of the amniotic fluid are no different from those of normal people.

The following checks can be done:

(1) Type B ultrasound examination: The method of measuring the amount of amniotic fluid by measuring the vertical depth of a single maximum dark area of ​​amniotic fluid (AFD) shows that the distance between the fetus and the uterine wall increases. If it exceeds 7 cm, it can be considered as polyhydramnios (some scholars believe that polyhydramnios can only be diagnosed when it exceeds 8 cm). If the amniotic fluid index (AFI) method is used, that is, the pregnant woman lies flat with her head at 30°, the navel and the linea alba are used as landmarks, the abdomen is divided into 4 parts, and the maximum amniotic fluid dark area in each quadrant is measured and added together. Domestic data show that >18cm is considered polyhydramnios. However, Phelan believes that it can be diagnosed only when it is >20cm. The comparison showed that AFI was significantly better than AFD. When there is too much amniotic fluid, the fetus only occupies a small part in the uterine cavity, and its limbs are free and floating in the amniotic fluid. Fetal malformations, twins, etc. can also be discovered at the same time.

(2) Amniocentesis and fetal angiography: In order to understand whether the fetus has gastrointestinal malformations, 20-40 ml of 76% diatrizoate meglumine is first injected into the amniotic cavity. After 3 hours, the film is taken. The contrast agent in the amniotic fluid decreases and contrast agent appears in the fetal intestine. Then, 20 to 40 ml of 40% iodized oil (depending on the amount of amniotic fluid) is injected into the amniotic cavity, and the baby is turned left and right several times. Because the fat-soluble contrast agent has a high affinity for vernix caseosa, films are taken half an hour, 1 hour, and 24 hours after the injection. The fetal body surface, including the head, trunk, limbs, and external genitalia can all be visualized. Amniocentesis may cause premature birth and intrauterine infection, and the contrast agent and radiation may cause certain damage to the fetus, so it should be used with caution.

(3) Detection of fetuses with neural tube defects; this type of fetal malformation is prone to be accompanied by polyhydramnios.

A woman's body is in a very special period when she is pregnant. Therefore, it is recommended that female friends must pay more attention to protecting themselves during the pregnancy, and not let themselves leave any sequelae due to carelessness. They should also try to avoid being picky about food to avoid malnutrition and other phenomena.