What is the normal amount of amniotic fluid during childbirth?

Amniotic fluid is an external environment in a woman's uterus during pregnancy. That is to say, the amount of amniotic fluid directly affects whether the fetus is healthy. Therefore, regular checks are needed during prenatal examinations. Water breaking will occur when delivery is approaching. So how much amniotic fluid is normal during delivery? Generally speaking, the standard is that the depth can reach 3 to 8 centimeters, and the index standard should be around 8 to 18 centimeters. Let's take a look at this aspect.

How much amniotic fluid is normal when the baby is about to be born?

The standard range of normal amniotic fluid depth is 3-8CM, and the standard range of amniotic fluid index is 8-18CM. As long as the amount of amniotic fluid is moderate, there is no problem.

Under normal pregnancy conditions, the production and absorption of amniotic fluid are in a dynamic balance, while polyhydramnios refers to the amount of amniotic fluid exceeding 2000ml during pregnancy. If the amount of amniotic fluid increases slowly, the symptoms are often mild, which is called chronic polyhydramnios; if the amniotic fluid increases rapidly within a few days and the compression symptoms are severe, it is called acute polyhydramnios.

The incidence of polyhydramnios is approximately 1%-3%. An appropriate amount of amniotic fluid can protect the fetus and the mother, but when the amount of amniotic fluid is too much, the incidence of maternal and fetal complications increases significantly. Therefore, pregnant women need to pay attention to their amniotic fluid during pregnancy and seek medical attention immediately if any abnormalities are found.

symptom:

1. Chronic polyhydramnios: more common. It usually occurs between 28 and 32 weeks of gestation. The specific manifestations are that the amniotic fluid slowly increases over several weeks, with mild compression symptoms or no symptoms. Most pregnant women can gradually adapt, and they only feel that their abdomen is growing faster. Examination showed that the uterus was under tension, the uterine height and abdominal circumference were greater than those of the same pregnancy, there was an obvious sensation of fluid tremor, the fetal position was clear or unclear, and the fetal heart rate was distant or unclear.

2. Acute polyhydramnios: less common. The disease usually occurs during the 20th to 24th week of pregnancy, with a sudden increase in amniotic fluid and a significant enlargement of the uterus within a few days. The patient feels abdominal pain, back pain, difficulty in movement, tight and shiny skin, and difficulty breathing and even cyanosis due to the elevated diaphragm, and cannot lie flat. Examination may reveal a highly distended abdomen, tense and thin skin, dilated inferior epigastric veins, and varicose veins and edema of the vulva; the uterus is larger than the gestational month and tense, the fetus cannot be examined clearly, and the fetal heartbeat is distant or unclear.

What is excessive amniotic fluid?

1. Fetal malformation: Among pregnant women with polyhydramnios, 18%-40% have fetal malformation. Neural tube defects are the most common, accounting for about 50%, of which open neural tube defects are the main ones. When the baby is anencephaly or has spina bifida, the meninges are exposed, the choroidal tissue proliferates, the exudation increases, and central swallowing disorders and antidiuretic hormone deficiency occur, which lead to excessive amniotic fluid formation and reduced reflux. Fetal esophageal and duodenal atresia can cause difficulty in the fetus swallowing amniotic fluid, causing polyhydramnios.

2. Chromosomal abnormalities: Trisomy 18, trisomy 21, and trisomy 13 fetuses may have difficulty swallowing amniotic fluid, causing polyhydramnios.

3. Twin pregnancy: About 12% of twin pregnancies are complicated by polyhydramnios, which is more than 10 times that of single pregnancy. In the case of monozygotic, monochorionic and diamniotic sacs, the two placentas have arteriovenous anastomosis, which can easily lead to twin-twin transfusion syndrome. The recipient fetus's circulating blood volume increases, the fetal urine volume increases, and polyhydramnios occurs.

4. Pregnancy complicated by diabetes: The mother's high blood sugar level leads to increased blood sugar in the fetus, producing osmotic diuresis, and increased placental and fetal membrane exudation leading to polyhydramnios.

5. Fetal edema: Polyhydramnios is related to fetal immune edema (such as hemolysis due to maternal-fetal blood type incompatibility) and non-immune edema (mostly caused by intrauterine infection).

6. Placental and umbilical cord lesions: Giant placenta and velamentous attachment of the umbilical cord can lead to polyhydramnios. When the diameter of placental chorioangioma is greater than 1 cm, 15%-30% may be accompanied by polyhydramnios.

7. Idiopathic polyhydramnios: accounts for about 30%, without abnormalities of the pregnant woman, fetus or placenta. The cause is unknown.