There are two types of cells in amniotic fluid. One type mainly comes from fetal epidermal exfoliation. The nucleus is small and dense. The ratio of nucleus to cytoplasm is 1:8, accompanied by a high percentage of non-nuclear cells. One type comes from amnion and the cytoplasm is deeply stained. The nucleus has a nuclear to cytoplasmic ratio of 1:3. There were few cells in the amniotic fluid before 12 weeks of gestation, and the cells from the amnion decreased after 32 weeks of gestation, and the number of non-nuclear polynuclear cells from the fetus increased at the full term. A staining of 1.36 mmol/L of Nile Blue Sulfate stained a portion of cells from the sebaceous glands to an orange color. The increase in such cells reflects the maturity of the fetus.

Basic Information

Specialist classification: maternity check check classification: biochemical examination

Applicable gender: whether women are fasting: not fasting

Tips: Empty urine before checking. Normal value

Oil soluble red O

Early pregnancy <0.10 (<10%).

Full-term pregnancy >0.50 (>50%).

Nile blue sulfate

Early pregnancy 0 (0%).

Full-term pregnancy >0.20 (20%).

Clinical significance

>0.20 indicates fetal maturity.

<0.10 indicates that the fetus is immature.

The incidence of amniotic fluid fat cells is correlated with the incidence of fetal respiratory distress syndrome. Pregnancy can occur in pregnant women with diabetes.

High results may be diseases: precautions for neonatal respiratory distress syndrome

In order to determine fetal maturity and suspected maternal and child blood group incompatibility, it should be carried out at the end of pregnancy.

Inspection process

Amniotic fluid collection:

The urine should be drained before surgery, with both hands on the hips and gently turn the waist and abdomen. Then supine, use B-ultrasound to detect the positioning, select the puncture point, and puncture under strict aseptic operation conditions. Generally, about 20 ml of amniotic fluid is taken and placed in a clean and sterilized centrifuge tube for immediate inspection.

Detection method:

Microscopic optical fluoroscopy imaging principle is adopted. After the smear is fixed by methanol or its fixed solution, the staining solution is selected according to the need, and then microscopic examination is performed.

Not suitable for the crowd

1. It is not advisable to have amniocentesis when pregnant women have a cold.

2, the consent of pregnant women and their families should be obtained before surgery, and pregnant women without indications should not be puncture.

Adverse reactions and risks


1, maternal injury: puncture needle stab wound blood vessels caused by abdominal wall hematoma uterine subserosal hematoma. Occasionally, amniotic fluid enters the maternal blood circulation from the puncture hole and causes amniotic fluid embolism. The bladder was not emptied before the puncture, and the bladder was injured.

2, damage to the fetus, placenta and umbilical cord: puncture needle damage to the fetus can occur bleeding, stab wounds and umbilical cord can also occur bleeding or hematoma. Therefore, the source of bleeding should be identified when taking hemorrhagic amniotic fluid. If you suspect that you are from a fetus, you should continue to listen to the fetal heart.

3, amniotic fluid leakage: postoperative amniotic fluid leakage from the needle hole, resulting in too little amniotic fluid, affecting fetal development, and even cause miscarriage or premature birth.

4, abortion or premature delivery: the incidence of abortion or premature birth 0.1% -0.2%, often occurred within one week after surgery, even after the puncture, premature rupture of membranes leading to premature delivery.

5, intrauterine infection: postpartum may have maternal fever. Intrauterine infection can cause abnormal fetal development, or even fetal death. Therefore, amniocentesis should be strictly aseptic.