What is the normal amniotic fluid index at 35 weeks of pregnancy?

Many people don't know much about the new project of testing the amniotic fluid of pregnant women, and don't know what the actual significance of this new project is. If the amniotic fluid is too little or too much, it will have a great impact on the fetus and may even cause the death of the fetus. The index to judge whether the amniotic fluid of pregnant women is normal is to check the amniotic fluid index. What is the normal amniotic fluid index at 35 weeks of pregnancy?

What is the amniotic fluid index at 35 weeks of pregnancy?

Amniotic Fluid Index (AFI): The umbilical line and the linea alba are used as markers to divide the uterus into four quadrants. The vertical diameter of the largest amniotic reservoir in each quadrant is accurately measured. The sum of the four is the amniotic fluid index.

The amount of amniotic fluid flow varies from person to person. It generally increases gradually with the increase of pregnancy weeks, about 50cc at 12 weeks, about 300-400cc in the second trimester, and reaches a maximum of about 1000cc at 36-38 weeks of pregnancy, and decreases significantly after the delivery period. In the early stages of pregnancy, the amniotic fluid is mainly composed of the amniotic membrane covering the embryo and the fetal umbilical cord. After four months, the amount and composition of the amniotic fluid can be adjusted by the fetus's swallowing of the amniotic fluid and urine. In addition, the entry and exit of the amniotic fluid into the respiratory tract will also have a certain effect.

Amniotic fluid examination is usually carried out between 16 and 20 weeks of pregnancy. It is performed by amniocentesis using the amniotic fluid of the pregnant woman. The examination items include cell culture, chromosome assessment, chromosome karyotype analysis, measurement of alpha-fetoprotein in amniotic fluid, biochemical examination of amniotic fluid, etc., in order to determine the perfection level and physical condition of the fetus, and to confirm whether the fetus is normal or suffers from some genetic diseases.

What are the items in the amniotic fluid examination?

1. Clinical symptoms

Pregnant women with excessive amniotic fluid may experience difficulty breathing and cannot lie flat because of their large uterus; patients with subacute excessive amniotic fluid may experience abdominal distension and pain, breath holding, sitting for breathing, and even cyanosis. Varicose veins are prone to occur in the lower limbs and private parts.

2. Pregnancy check

The uterine height, fetal abdominal circumference and weight curves were significantly higher than those of pregnant women in the same gestational weeks. The skin was weak during palpation, the fetal position was unclear, and the fetal heartbeat was slow.

3. B-ultrasound examination

If the amniotic fluid index (AFI) exceeds 20cm and the larger plane of amniotic fluid of the pregnant woman exceeds 8cm, it indicates that there is too much amniotic fluid.

The amniotic fluid index refers to the measurement of the larger dark amniotic fluid areas in each quadrant, with the abdomen divided into four quadrants with the umbilical horizontal line and the linea alba as landmarks, with the pregnant woman's head raised at 30 degrees and lying flat.

4. Basis for diagnosis: The total amount of amniotic fluid discharged during delivery is >2000mL.