Amniotic fluid

What is Amniotic fluid?

The amniotic fluid is present in the amniotic sac that women develop during pregnancy. It is a slightly yellowish, clear liquid that is present in the uterus and surrounds the fetus. The primary function is to ensure the proper growth, development and protections of the fetus. The amniotic fluid is also known as liquor amnii.

Composition of the Amniotic fluid:

The amniotic fluid consists of the following components –

  • Fetal wastes, mostly urine
  • Fetal skin cells
  • Water

Origin and production of Amniotic fluid:

During the first trimester and early part of the second trimester, the mother’s placenta produces amniotic fluid till the baby’s kidneys have developed sufficiently to produce the fluid by itself. The circulation of the amniotic fluid continues in a process that involves the swallowing of the fluid by the fetus when it breathes and then excreting it in the form of urine. The mother’s kidneys filter the fetal waste as it passes through the placenta, thus the urine that makes up the fluid is not complete waste material.

Functions of the Amniotic fluid:

Following are the functions that the Amniotic fluid performs during pregnancy –

  • Prevents to wall of the amniotic sac from sticking to the baby
  • It allows movement of the baby inside the uterus
  • Aids in the uniform growth of the organs and body parts of the baby
  • Helps in proper development of the bones and muscles
  • Keeps the baby healthy by maintaining a constant temperature
  • Ensures proper growth of the baby’s lungs because the baby breathes the fluid in and out while it is in the uterus
  • Helps in the proper formation of the baby’s digestive system
  • Prevents squeezing of the umbilical cord that performs the function of carrying oxygen and food to the fetus
  • The amniotic fluid that the baby swallows helps in the creation of the earliest stools of a newborn, known as meconium, and urine
  • Forms a cushion like protective layer that shields the baby from any external impact that can cause damage

Various levels of Amniotic fluid:

  • Low Amniotic fluid levels – Lack of amniotic fluid during pregnancy may lead to a condition known as Oligohydramnios. There are no significant symptoms of this disorder, however, a belly being smaller in size according to the woman’s gestational age, is an indication of this problem. Serious complications such as birth defects, miscarriages, still births, premature birth, etc. are possible outcomes of oligohydramnios. Women who suffer from hypertension, gestational diabetes, preeclampsia and high blood pressure at the time of pregnancy are at a higher risk of experiencing a lack of amniotic fluid during pregnancy. Regular ultra sounds and other forms of fetal monitoring are the best ways of treating this deficiency.
  • Normal Amniotic fluid levels – It is important for women to try and maintain the normal level of amniotic fluid when they are pregnant because low or high levels of amniotic fluid are capable of creating complications during childbirth. Normally, the volume of the fluid increases continuously till the 34th – 36th week of pregnancy and at this time the amniotic sac contains about one-fourth of the average volume of the fluid. After this the volume of the fluid decreases gradually till the time of delivery. Water breaking is the term that refers to the draining of the fluid through the vagina after the amniotic sac ruptures, this may occur before or at the time of labor.
  • High Amniotic fluid levels – Polyhydramnios refers to a condition in which there is an excess of the amniotic fluid during pregnancy. Edema, excessive weight gain and difficulty in breathing are some of the characteristic symptoms of such a condition. Possible causes of Polyhydramnios can be maternal diabetes, fetal abnormalities, high levels of fluid, infectious conditions, etc. The complications of Polyhydramnios during pregnancy are similar to the complications associated with oligohydramnios along with congenital problems like Down syndrome and Cleft palate. Weekly ultrasounds and karyotyping are some forms of treatment for this disorder.

Amniotic fluid Index chart:

To determine the well being of the fetus, the Amniotic fluid index (AFI) is used to estimate the level of the fluid in the uterus. Such observations are an essential part of the fetus’ biophysical profile. An ultrasound of the uterus determines the AFI which is measured in cm. The most common procedures to find out the AFI are through the four quadrant technique or by examining the single deepest pocket. The former technique involves measuring the length of the four separate fluid pockets, vertically in each quadrant to calculate the total volume of the fluid.

Tests and Analysis for Amniotic fluid:

  • Vaginal pH test Normally, the pH level for amniotic fluid ranges between 7.0 – 7.5 and 3.8 – 4.5 for the upper vaginal pH. Many fetal abnormalities can be uncovered through this test. Ph levels higher than 4.5 on the pH strip test indicate a rupture in the amniotic membrane. Other tests to check the fetal development, fluid leakage and fluid levels include regular fundal height measurement, nitrazine paper test, fern test, etc.
  • Amniotic fluid analysis – A process called amniocentesis that involves collecting a sample from the mother’s abdomen which helps to examine the baby’s health development. Risk of any genetic defects and gender determination are also possible due to the fetal cells present in the fluid.

Symptoms of leaking Amniotic fluid:

During any stage in the pregnancy, it is possible for women to experience leakage of amniotic fluid through the vagina which can cause severe complications during delivery. However, there are chances that people may confuse sweating, discharge of urine during the third trimester, etc. as leakage of the amniotic fluid. Following are the symptoms of leaking amniotic fluid –

  • Identifying the amniotic fluid is possible as it may have a yellowish, brownish, or greenish coloration with cloudy appearance. Blood in the fluid may cause it to have a red or pinkish coloration which is a sign of abnormality in the fetus. Some women may discharge amniotic fluid that is completely clear, thus making it difficult to identify.
  • The smell of urine is similar to ammonia, whereas amniotic fluid has a characteristic sweet smell. This odor makes it unique and easier to identify.

Complications related to Amniotic fluid:

Both, high and low levels of amniotic fluid can give rise to the following complications during pregnancy:

  • Amniotic Band Syndrome (ABS) – This syndrome refers to a defect that occurs within the womb. It is a condition in which certain body parts of the fetus get caught in bands or tiny strings. Such a case is only possible when the outer membrane of the placenta remains intact while the inner membrane ruptures, which results in the fluid containing stringy pieces that float in it. It is possible for some body parts like the toes and fingers of the growing baby to be deprived of blood supply as the strings may get entangled on certain parts of the body. Cleft palate, club foot, absent or short of fingers or toes, etc. are possible birth defects that may result due to amniotic band syndrome. The most effective and common treatment for such a complication is disentangling the strings by performing a surgery in-utero.
  • Meconium Aspiration Syndrome – Meconium is the first feces that a baby passes a short time before delivery. This meconium then mixes with the amniotic fluid. Various congenital conditions such as hearing loss, limpness as birth, hearing loss, etc. are possible outcomes of the baby inhaling the mixture into the lungs and it is known as meconium aspiration syndrome. If the condition is severe it could also lead to death of the infant.
  • Amniotic Fluid Embolism (AFE) – This is a rare condition that involves the triggering of allergic reactions when fetal cells, hair and other debris and other fetal material enter the mother’s bloodstream through the bed of the placenta. Symptoms of this condition include nausea, sudden decrease in blood pressure, shortness of breath, pulmonary edema, cardiovascular collapse, seizures, etc. Severe cases may lead to brain death, neurological damage and other life threatening complications.
  • Chorioamnionitis (Intra Amniotic Infection) – A bacterial infection of the amniotic fluid before or during labor and it is known as Chorioamnionitis or simply as, amnionitis. The most common groups of germs that cause this kind of a disorder are anaerobic bacteria, group B streptococci, E. coli, etc. Presence of bacteria in the blood of the baby and mother known as bacteremia, heavy blood loss during and after delivery of the baby, c – section delivery, etc. are possible complications associated with this condition.

Ways to increase the level of Amniotic fluids:

Following are certain medical methods used to temporarily increase the level of amniotic fluids –

  • Maternal Re-hydration – Use of oral and intra venous fluids to rehydrate the mother is involved in this procedure. Doctors often advise pregnant women to drink lots of water to maintain the correct level of amniotic fluids in the body and keep them hydrated.
  • Amnioinfusion – Involves instilling a saline solution into the amniotic sac to increase the quantity of amniotic fluid.

Stem cells and Amniotic fluids:

The presence of a considerable amount of stem cells in the amniotic fluids has recently been proved by experts. These pulripotent cells can be of great use in the future of medical applications, as they can differentiate in various tissues such as bone, skin, cartilage, muscles, etc.

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