Abnormalities in the color and volume of amniotic fluid

This is an automatically translated article.

The article was professionally consulted by Dr. Nguyen Anh Tu - Doctor of Obstetric Ultrasound - Prenatal Diagnosis - Obstetrics Department - Vinmec Hai Phong International General Hospital.
Abnormalities in the color and volume of amniotic fluid can be acute or chronic, with physiological or pathological causes. Amniotic fluid abnormalities can increase morbidity and increase the risk of death for both mother and baby.

1. The role of amniotic fluid

The fetus is in the mother's uterus surrounded by amniotic fluid. Amniotic fluid is a medium rich in nutrients and has the ability to regenerate and exchange. It plays an extremely important role in the life and development of the fetus while in the womb.
In the early stages, amniotic fluid begins to form due to the permeation of the mother's serum through the amniotic membrane, or the permeation of the baby serum through the fetal skin. In the later stages, when the fetus is 10-12 weeks old, amniotic fluid is formed by urine secreted from the kidneys and lung fluid of the fetus. When the fetus is 16-32 weeks old, the amount of amniotic fluid reaches from 250ml-800ml, then increases to 1000ml, it maintains until the fetus is 36 weeks old. From this point until the baby is born, the amount of amniotic fluid will gradually decrease and only about 500ml remains. Therefore, the older the fetus, the less amniotic fluid will be.
Amniotic fluid has the function of nourishing the embryo by reabsorption of amniotic fluid, which is done mainly through the fetal digestive system. From the 20th week of pregnancy, the fetus has begun to swallow amniotic fluid. In addition, amniotic fluid is also reabsorbed through the umbilical cord, the amniotic membrane, and through the fetal skin. From the 24th week of pregnancy onwards, the fetus absorbs from 300ml-500ml of amniotic fluid per day. This amount of amniotic fluid will enter the blood to contribute to the balance of fluids in the body of the fetus and will be partially filtered to form urine for the baby, entering the intestines to contribute to the formation of meconium.

Amniotic fluid also has the function of protecting and protecting the fetus from collisions, trauma and especially ensuring a sterile environment for the baby in the amniotic sac. Mechanically, amniotic fluid creates an environment for the fetus to develop normally and harmoniously in the mother's genital tract during the last months of pregnancy. During labor, amniotic fluid will continue to protect the fetus from the trauma of uterine contractions and infection. Amniotic fluid helps to form the amniotic sac and dilates the mother's cervix, making it easier to clear the cervix.
After the rupture of membranes, the oily nature of the amniotic fluid has the role of lubricating the mother's genital tract, making it easier for the fetus to be born. Thus, amniotic fluid is a circulating fluid, from the second trimester, amniotic fluid originates largely from fetal excretion from the urinary tract and amniotic fluid is reabsorbed by fetal swallowing through the digestive system. Amniotic fluid is normal when:
In terms of volume: Amniotic fluid changes from 50ml when the fetus is 4 to 8 weeks old to 1000ml when the fetus is 38 weeks old. After that, the volume of amniotic fluid tends to decrease gradually to about 500-800ml by the 40th week of pregnancy and until the time of labor and delivery of the baby. About color: At the beginning of pregnancy, amniotic fluid is clear white. As the fetus grows, the color of the amniotic fluid will become whiter due to the presence of many substances. The fetus is mature enough (from the 38th week), the amniotic fluid will have a milky white color similar to the water from washing rice. Through surveying the pathology of amniotic fluid, we can assess the health status and some pathologies of the fetus. Amniotic fluid can be abnormal in color and volume.

2. Abnormalities in volume

2.1 Polyhydramnios When the volume of amniotic fluid is greater than 2000ml: Common in cases of multiple pregnancies and some abnormalities of the fetal central nervous system such as anencephaly, hydrocephalus, meningeal hernia, split spine,... Polyhydramnios can also be caused by pathological causes of the amniotic membrane, or of the umbilical cord placenta, large fetus, and placental edema. Or the mother's disease such as the mother has diabetes, ... or idiopathic.
Effects of polyhydramnios on fetal development and health: If polyhydramnios is caused by malformations or malformations, the prognosis is very poor. Polyhydramnios will make the baby quite mobile in the uterus, so it is easy for the umbilical cord to wrap around the neck, abnormal position. Polyhydramnios causes the mother's abdomen to become larger than usual, especially acute polyhydramnios. Mothers find it difficult to breathe, are prone to uterine contractions, and premature labor increases the mortality rate during childbirth. During labor, polyhydramnios is very likely to be the cause of prolonged labor, making the baby more likely to fail, and the mother to have uterine atony, causing postpartum haemorrhage. At the same time, polyhydramnios will lead to the risk of sudden rupture of membranes and the complications of sudden rupture of membranes are: placental abruption, umbilical cord prolapse, abnormal position and amniotic fluid embolism.
Amniotic fluid embolism is a complication that can be said to be the most dangerous for pregnant mothers. This is a condition in which amniotic fluid is present in the mother's circulation, causing embolism, acute respiratory failure and circulatory failure. Amniotic fluid embolism has no factors, warning risks as well as ways to prevent it, although it is a rare disease, it has a very serious impact, more than 50% of cases die. These are life-threatening for both mother and child.
2.2 Oliguria (less amniotic fluid) and amniotic fluid When the amniotic fluid volume is less than 200ml: Common in fetal urinary and digestive system abnormalities such as esophageal stricture, absence of stomach, posterior urethral valve in male babies , renal aplasia.... Oliguria is also seen in maternal malnutrition, fetal malnutrition, pregnancy past due date, premature rupture of membranes, premature rupture of membranes....
Effects of oligohydramnios on development Fetal development: oligohydramnios, if present early in the second trimester, has a great influence on the development of the fetus. If not due to birth defects, the baby also has great consequences because of prolonged oligohydramnios: Congenital dislocation of the hip, stiffening of the joints, club legs due to not being able to move well in the uterus with little water. amniotic fluid, pulmonary hypoplasia causing respiratory failure. In the third trimester, if oligohydramnios is often due to the baby's malnutrition, the risks are also great: The risk of clubfoot, arthralgia, pulmonary hypoplasia and, importantly, compression of the umbilical cord, the baby is more likely to fail. Pregnancy and not correcting the position of the fetus may have abnormal positions causing difficulty in delivery. If the water breaks, causing oligohydramnios when not in labor or at the beginning of abdominal pain at birth, it can easily lead to the risk of amniotic fluid infection, thereby causing fetal infection, uterine infection... both mother and baby are dangerous , are affected to health and life.
oligohydramnios causes harm to the fetus such as the risk of deforming the limbs (club, crooked), facial muscle deformity, low birth weight, even fetal death, severe umbilical cord compression during labor, seizure disorder hill. Harm to the mother as: irregular contractions, leading to labor problems.
To treat pregnant women with oligohydramnios, it is necessary to determine the cause; assess the extent, progress and consequences for the fetus; delay until the fetus is mature enough - increase the amount of amniotic fluid by drinking water or infusing water into the amniotic cavity. When the fetus is large enough to support life, it is possible to terminate the pregnancy early to save the pregnancy. Even parents will have to accept abortion, because the fetus has a serious disease, a high prognosis of death, or a serious abnormality
2.3 How to evaluate amniotic fluid volume Ways to assess amniotic fluid volume Including:
Based on clinical examination: by palpating the abdomen, palpating the fetal part as well as the transvaginal examination, the clinician can know whether the amniotic fluid is more or less. However, in order to estimate the amniotic fluid volume more accurately, we must rely on ultrasound to measure the amniotic fluid spaces in the amniotic chamber. in the assessment of amniotic fluid volume through ultrasound. Most commonly, amniotic fluid index is measured by adding the total of 4 amniotic fluid compartments in the 4 corners of the amniotic cavity.

The amount of amniotic fluid is estimated by ultrasound, calculated by dividing the mother's abdominal cavity into four parts and then measuring the largest amniotic cavity (cm) in each part and adding them together, so we have the amniotic fluid index as follows:
Index Normal amniotic fluid from: 6-12 cm
Abnormal amniotic fluid index :
Polyhydramnios: greater than or equal to 20cm (>=20cm) Oliguria: less than or equal to 5cm (<= 5cm) Amniotic fluid: less than 3cm ( < 3cm) In addition, one can use methods such as finding the largest amniotic cavity in the amniotic cavity, through ultrasound to assess the volume of amniotic fluid. It is considered oligohydramnios when the largest amniotic cavity is still less than or equal to 3cm.
However, the measurement of amniotic fluid index by ultrasound must be evaluated at least 2 times in a row, 2 to 6 hours apart to determine whether oligohydramnios or excess amniotic fluid are present. Amniotic fluid color can change very quickly in as little as 30 minutes to 2 hours, and amniotic fluid volume can change in as little as 12 hours.

3. Irregularity in color

Abnormalities in the color of amniotic fluid include:
Amniotic fluid is yellow-green: Hemolysis of the fetus or fetal growth retardation in the uterus. Amniotic fluid is dirty or has a green mossy color, even with the baby's stools: The fetus is severely weakened in the womb, threatening the life of both mother and baby. Amniotic fluid is cloudy as well as pus, and may be accompanied by a foul odor: it is an infection of the amniotic fluid, which puts the baby at high risk of infection in the uterus. Amniotic fluid is red-brown: it means that the baby is not alive or the fetus has been stillborn in the womb

Amniotic fluid color is seen by amniocentesis in cases where the cervix dilates larger than 1cm or amniocentesis through the abdominal wall. When the amniotic fluid breaks spontaneously or when amniotic fluid is pressed, the color of amniotic fluid can be seen accurately and clearly.
For pregnancy, amniotic fluid plays a very important role, possibly equal to the uterus, placenta and tangled cord in the role of nurturing and protecting the fetus. Thanks to the survey of the color, volume and density of amniotic fluid, one can predict and predict the health and development of the baby still in the womb.
Therefore, during pregnancy, the mother needs to periodically monitor to ensure the quality of amniotic fluid. If you see any unusual symptoms, you should consult a specialist medical facility for appropriate treatment. Doctors will assess the quality of amniotic fluid through the color of the amniotic fluid. Usually the amniotic fluid of a preterm fetus is colorless. As the fetus grows larger, the substance clinging to the fetus's skin comes off, so the amniotic fluid will be milky white like rice water. If the amniotic fluid is clear white, cloudy, it is good; but if amniotic fluid is green, yellow is not good. During the mother's labor, if the doctor finds that the amniotic fluid has many stools (ejected from the fetus) will have appropriate treatment, because at this time, the baby may be suffocating due to lack of oxygen.
Vinmec International General Hospital offers a Package Maternity Care Program for pregnant women right from the first months of pregnancy with a full range of antenatal care visits, periodical 3D and 4D ultrasounds and routine tests to ensure that the mother is healthy and the fetus is developing comprehensively.
Doctor Nguyen Anh Tu has 6 years of experience in obstetrics and gynecology ultrasound, specially researched and trained in pregnancy ultrasound - prenatal diagnosis. Dr. Tu has completed courses on ultrasound - prenatal diagnosis of the FMF International Fetal Medicine Association; trained in consulting and implementing diagnostic intervention techniques in fetal medicine and participated in many specialized conferences and seminars on Fetal Medicine
Currently working as a doctor at the Hospital's Department of Obstetrics and Gynecology Vinmec Hai Phong International General Hospital

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