Amniotic fluid has many jobs throughout pregnancy. It protects the foetus and helps it grow, and it also makes labour and delivery easier. For individuals seeking to become doctors, it’s crucial to understand what AFI does during pregnancy, its typical levels, and potential problems that can arise from it. 

DocTutorials has carefully crafted a NEET PG exam-based curriculum that makes it easier to understand complex topics, such as amniotic fluid. Read on to learn more about amniotic fluid, its roles, related illnesses, and other things. 

What is the Fluid in the Amniotic Sac?

The amniotic fluid is a transparent, watery material that protects the foetus in the amniotic sac during pregnancy. It was initially composed of maternal plasma, but approximately 20 weeks into the pregnancy, foetal urine slowly takes its place. Amniotic fluid helps the foetus grow by making it easier for the lungs, digestive system, and muscles to develop. 

It also has hormones, antibodies, and other important nutrients that keep the foetus from getting sick. It is essential to maintain the proper amount of amniotic fluid, as both too little (oligohydramnios) and too much (polyhydramnios) can lead to health concerns. 

What Does Amniotic Fluid Do?

During pregnancy, amniotic fluid performs many important functions to keep the foetus growing and safe. The AFI (Amniotic Fluid Index) keeps an eye on it all the time during pregnancy to make sure that the levels of amniotic fluid stay within the normal ranges on the amniotic fluid index chart. 

These are the main jobs of amniotic fluid:

Covering and Protecting 

Amniotic fluid acts as a natural shock absorber, keeping the foetus safe from outside harm or sudden movements of the mother, such as falling. The amniotic fluid protects the foetus by cushioning it inside the amniotic sac.

Keeping the Temperature Intact

The fluid keeps the foetus warm and stable by insulating it. Thermoregulation is necessary for the foetus to keep growing, especially in the last several weeks of pregnancy.

Infection Control Amniotic fluid contains important antibodies and other immunological components that help protect the foetus against infection. This helps keep the inside of the uterus safe, regardless of the amount of amniotic fluid present.

Building Muscle and Bone 

The fluid helps the bones and muscles grow by allowing them to move freely within the amniotic sac. It helps the foetus build strong bones and muscles by preventing problems like stiff joints or webbing of the fingers and toes, which can happen when there isn’t enough fluid (oligohydramnios).

Development of the Respiratory and Digestive Systems 

The foetus eats and “breathes in” amniotic fluid all the time. This procedure helps the baby’s lungs and digestive system develop, preparing them for life outside the womb.

Protection for the Umbilical Cord 

Amniotic fluid keeps the umbilical cord from being squeezed. Controlling the levels of amniotic fluid lowers the risk of blood flow being blocked. The baby can continue to grow properly since the flow of oxygenated and nutrient-rich blood is not blocked.

Helps Develop the Immune System 

Amniotic fluid helps the foetus and builds its immune system so that the infant can interact with the outside world when it is born.

Makes Labour and Delivery Easier 

When the amniotic sac breaks, which usually happens during the first stage of labour (sometimes called “water breaking”), the fluid starts to leak out through the vagina and cervix. This event indicates that the labour is still ongoing, and a medical professional needs to intervene immediately.

What Disorders Can Happen with Amniotic Fluid?

When the levels of amniotic fluid change or are not where they should be, it might cause problems. Ultrasound-based tests, such as the AFI (Amniotic Fluid Index), can detect these imbalances during pregnancy, which can be detrimental to both the mother and the baby. 

The following are the most common problems with amniotic fluid:

Oligohydramnios( means having low levels of amniotic fluid)

When the amniotic fluid volume falls below the normal AFI range, it is referred to as oligohydramnios. This happens when the pregnancy AFI is less than 5 cm or the maximum vertical pocket (MVP) is less than 2 cm. 

This problem can occur if the amniotic sac breaks and leaks, if the foetus doesn’t grow sufficiently, if the foetus doesn’t move about as much, or if the placenta isn’t functioning correctly. Maternal health problems like preeclampsia, high blood pressure, diabetes, lupus, or a history of having a baby with limited growth further raise the risk.

Polyhydramnios (too much amniotic fluid)

If the AFI pregnancy reading is more than 24 cm or the Maximum Vertical Pocket (MVP) is greater than 8 cm, the person has polyhydramnios, also known as hydramnios. 

Some of the most common causes of this condition are intrauterine growth restriction, foetal malformations (including oesophageal atresia and anencephaly), maternal diabetes, and Rh incompatibility.

Chorioamnionitis

Bacteria cause this infection in the amniotic fluid, membranes, or placenta. Bacteria that travel from the vagina to the uterus are frequently to blame. Chorioamnionitis that hasn’t been recognised yet can lead to serious problems like premature birth, infection in the newborn, or sepsis in the mother and baby.

Premature (Prelabor) Rupture of Membranes (PPROM) 

This condition develops when the amniotic sac breaks and fluid starts to leak before 37 weeks of pregnancy and before labour starts. If you don’t closely watch your pregnancy after PPROM, the danger of infection increases, which can lead to preterm labour or other problems for both the mother and the baby.

Why is Amniotic Fluid Important for the Foetus?

Here are the main ways that amniotic fluid helps the foetus grow, with a focus on its clinical importance and how AFI is used to monitor pregnancy:

Protects the Foetus

The fluid acts as a natural cushion, absorbing shocks and protecting the fetus from external damage, including falls or pressure on the abdomen. This function lowers the chance of harm in the womb, especially when the mother moves suddenly. So, it is very important for the protection of the foetus to keep the amniotic fluid at a normal level.

Allows Free Foetal Movement

The amniotic sac is filled with fluid, which provides the embryo with sufficient space to move about freely. This is helpful for the development of the bones and muscles. Without this space, the embryo would have problems with its growth. 

It also ensures that the umbilical cord isn’t pinched, allowing blood and nutrients to flow uninterrupted. Doctors use the AFI chart throughout pregnancy to make sure that the fetus has enough room to move about in the amniotic sac.

Prevents Foetal Infections

Antibodies and other immune components are also in amniotic fluid. These protect the embryo against infection. It is the first line of defence against harmful germs, which is especially crucial during the early stages of pregnancy when the baby’s immune system isn’t fully developed yet. 

Monitoring the AFI pregnancy value can help identify signs of infection, such as those associated with chorioamnionitis.

Keeps the Temperature Steady

The fluid keeps the womb at a constant temperature of approximately 37.5°C, which maintains the foetus’s warmth. This is particularly important for good growth, especially in areas where the weather fluctuates significantly. During routine thermal and overall health checkups, healthcare providers check the amounts of amniotic fluid.

Supports Lung Development

The foetus starts to “breathe” by taking in and letting out amniotic fluid as early as 10 to 11 weeks of pregnancy. This continues until roughly 36 weeks, when the lungs are fully developed. 

The AFI normal value at 32 weeks is significant, as this is when the lungs begin to mature. If the AFI value is abnormal, it may indicate that the lungs are not fully developed or that there are other underlying issues.

Aids Maturity of the Digestive System

The foetus swallows the amniotic fluid, which passes through its digestive system and is expelled as urine later. This procedure helps the gastrointestinal tract function more effectively. 

Too much amniotic fluid can also mean that there is a blockage or a problem with swallowing, like oesophageal atresia. This is typically determined by examining the AFI chart in centimetres during pregnancy.

FAQs About Amniotic Fluid Dynamics

1. What is the importance of AFI during pregnancy?

The Amniotic Fluid Index (AFI) is a test that measures how much amniotic fluid is around the fetus during pregnancy. It helps keep an eye on the health of the foetus and finds problems like oligohydramnios or polyhydramnios.

2. What is the usual AFI at 32 weeks in cm? 

A normal AFI (Amniotic Fluid Index) at 32 weeks of pregnancy is between 9 and 16 cm. This is normal, as the usual AFI range is 5-25 cm.

3. During pregnancy, how much amniotic fluid is normal in ml?

During a normal pregnancy, the amount of amniotic fluid typically peaks at approximately 800 ml between weeks 32 and 34, then gradually decreases to around 600 ml by week 40.

4. How do you measure amniotic fluid during pregnancy?

Ultrasound is used to measure AFI by summing up the largest vertical pockets of fluid in each quadrant of the uterus. The AFI chart displays the results in centimetres and compares them to normal values based on the stage of pregnancy.

5. What does it indicate if my AFI is lower than normal?

A low AFI value, less than 5 cm, implies oligohydramnios. This may need to be watched more closely or treated. Knowing the usual range for AFI during pregnancy can help identify this kind of problem early on.

Conclusion

Any medical student, but especially NEET PG students, needs to understand how amniotic fluid functions, its typical range, and potential problems associated with it. Being able to consistently check the AFI during pregnancy and understand what a normal amniotic fluid index means can help find problems early on. 

For learning in a planned manner, DocTutorials offers a wide range of NEET PG study materials. These include a structured curriculum, video lectures, and notes that help young medical students better understand complex concepts, such as amniotic fluid.

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