Amniotic Fluid: Its Role and Importance in Pregnancy

Author :-

Dr.Sreejaya

General Medicine & Diabetology

Introduction to Amniotic Fluid

What is amniotic fluid?

Developmentally, amniotic fluid has several roles. Amniotic fluid physically protects the fetus from maternal abdominal injuries. By cushioning the umbilical cord, it reduces the danger of uterine wall compression against the fetus. Antibacterial amniotic fluid protects the fetus from infectious agents. In addition, it stores proteins, electrolytes, immunoglobulins, and vitamins from the mother for the fetus.

How Amniotic Fluid Forms and Its Functions

The formation of amniotic fluid occurs early and late in pregnancy. Early gestation is from fertilisation until 8 weeks, while late gestation is from 8 weeks until birth. The composition of amniotic fluid varies between early and late gestation. During the embryonic era, amniotic fluid comes from maternal serum, coelomic fluid, and amniotic cavity fluid; during late gestation, fetal urine and lung secretions provide most of it.

Role of amniotic fluid in pregnancy

Cushioning and Protecting the Fetus

Amniotic fluid is a key gauge of pregnancy health and advancement. Clinicians can use the AFI, which stands for the single deepest pocket. The biophysical profile encompasses factors such as fetal tone, breathing patterns, and non-stress tests. Ultrasound estimates amniotic fluid volume (AFI) and SDP. Increased amniotic fluid is polyhydramnios, defined as an AFI or SDP over 24 cm or 8 cm. GI blockage, genetic abnormalities, musculoskeletal problems, and congenital diaphragmatic hernias can cause polyhydramnios. OLIGOhydramnios has an AFI or SDP ≤ 5 cm. IUGR, renal agenesis, and genitourinary tract blockage can result from oligohydramnios.

Supporting lung development and growth.

Liquid fills the foetal lungs. This fetal lung-produced liquid leaves the trachea, is ingested, or enters the amniotic sac. Fetal lung fluids keep the lungs swollen, promoting growth. Future airways must retain liquid to maintain the lungs' proper expansion rate, which drives development. Most diseases and abnormalities, which cause deficient fetal lung development, likely limit lung liquid volume and expansion.

Regulating temperature and movement for the baby

On the biophysiological level, temperature and amino acids play pivotal roles. The prominent capability is to regulate the body temperature, which gradually improves as the baby grows. Most babies start developing efficient mechanisms of thermoregulation. All their bodies become better equipped in terms of adaptability. Every baby has a different ability to regulate the body temperature; hence, paying attention to the baby is of utmost importance here.

Understanding Amniotic Fluid Levels

Normal vs. Abnormal Levels of Amniotic Fluid

Normalcy:

From amniotic fluid:

The fluid protects the foetus by absorbing external pressure.

Infant temperature control: The fluid insulates and warms the infant.

Infection control: antibodies in amniotic fluid.

As the newborn breathes and swallows amniotic fluid, its lung and digestive system muscles mature.

Development of muscles and bones: The infant's freedom of movement within the amniotic sac allows for the growth of muscles and bones.

Lubrication Amniotic fluid inhibits fingers and toes from developing together; low amounts can cause webbing.

Uterine fluid supports the umbilical cord. Through this channel, food and oxygen from the placenta reach the fetus.

Abnormalities

Amniotic fluid levels might vary due to certain circumstances.

Amniotic fluid levels might vary due to certain circumstances.
Insufficient amniotic fluid is oligohydramnios.
Polyhydramnios—hydrology or amniotic fluid disorder—is too much fluid.
Oligohydramnios
In 4% of pregnancies and 12% of post-date pregnancies, oligohydramnios occurs.
The maximum vertical pocket (MVP) is less than 2 cm and the amniotic fluid index (AFI) is less than 5 cm on ultrasound, indicating oligohydramnios.
This may be visible in situations where the amniotic membrane is torn, measures tiny for a given stage of pregnancy, or does not move as predicted.

Mothers with any of these medical disorders may also experience it:

previous growth-restrictional pregnancies
continuous hypertension
Abruption and placental issues
preeclampsia
Lupus and diabetes
Birth problems, such as kidney abnormalities, and late delivery can result from several pregnancies.
Unknown causes, called idiopathic

Polyhydramnios: High Amniotic Fluid Levels and Causes

Amniotic fluid production and resorption are in dynamic balance under physiological settings. Foetal urination and lung liquid production affect fluid levels. Foetal swallowing and intramembranous/intravascular absorption resorb amniotic fluid. Each mechanism's proportional importance changes throughout pregnancy. Swallowing problems or excessive urination might cause polyhydramnios.

Oligohydramnios: Low Amniotic Fluid Levels and Risks

Reduced amniotic fluid volume (AFV) for gestational age is oligohydramnios. After 34 to 36 weeks, the AFV levels off (about 400 mL) and remains steady until term. The AFV progressively decreases after 40 weeks, reducing post-term volume. The pattern permits fundal height measurements and ultrasound examination of AFV during pregnancy. [2] The differential diagnosis should include amniotic fluid abnormalities when fundal height and gestational age vary.

The Role of the Placenta in Regulating Amniotic Fluid

How Placenta Fluid Supports Fetal Development

After fertilisation, the blastocyst implants in the uterine wall and forms the placenta five to 10 days later. Inner cell mass creates the fetus and fetal membranes, while outside trophoblast cells form the placenta. Placental villi adhere to the uterine wall and remodel the spiral arteries to supply maternal blood, oxygen, and nutrients after implantation. Reshaping expands vessels and alters blood flow to be low-resistance and fast.

Placental Health and Its Impact on Amniotic Fluid Levels

Mesenchymal, hemotopoietic, trophoblastic, and possibly primitive stem cells are present in the amniotic fluid and placenta. Much of the amniotic cavity/fluid and placenta have an embryonic origin, although their stem cell origins are unknown. It's unclear if these two stem-cell subgroups are identical. We're still learning about the stem cell populations from these two sources' multilineage potential. The lack of clinical use of these cells is hardly surprising.

Monitor niotic fluid levels during pregnancy.

Importance of Regular Fetal Monitoring

Common disorders like oligohydramnios and polyhydramnios can harm pregnant women. Prenatal care providers should be aware of disorders that require heightened screening and aberrant results. Due to the high risk of foetal abnormalities, the treatment team should include anatomic ultrasound specialists. Paediatric radiologists and maternal-foetal medicine doctors are examples.

How Amniotic Fluid Index (AFI) is Measured

Ultrasound for amniotic fluid measurement. We measure the amniotic fluid index by dividing the uterus into four imaginary quadrants. The linea nigra divides the uterus in half. Lumbricus divides upper and lower parts.

We position the transducer parallel to the patient's longitudinal axis and perpendicular to the floor. In each quadrant, centimeters measure the deepest, unobstructed vertical fluid pocket. FIGURE 2. Next, we sum the four pocket measurements to compute AFI. AFI is usually 5–25 cm. The ACOG says that to diagnose oligohydramnios, the deepest vertical pocket of amniotic fluid with a volume of 2 cm or less should be used instead of an amniotic fluid index of 5 cm or less.

What Happens During Fetal Ultrasounds for Amniotic Fluid Assessment

Assessing amniotic fluid volume is crucial in basic obstetric ultrasonography exams. Usually, we estimate amniotic fluid using the single maximum vertical pocket, also known as the amniotic fluid index. The MVP approach selects the biggest amniotic fluid pocket on an ultrasound, free of cord and fetal components, and measures its maximum vertical size with the transducer perpendicular to the floor. The amniotic fluid index (AFI) approach involves dividing the uterus into four equal quadrants, measuring the deepest vertical pocket of fluid in each quadrant (similar to MVP), and combining the data. Sonologists and sonographers often assess MVPs and AFIs in amniotic fluid pockets that are at least 1 cm wide and free of cord and fetal components.

Fetal Growth and Amniotic Fluid Levels

How Amniotic Fluid Levels Affect Fetal Growth

Developed by Phelan and Rutherford, the amniotic fluid index is the sum of the vertical diameter of the biggest pocket in each quadrant with the maternal umbilicus as a reference. Orient the transducers longitudinally, ensuring that each pocket is one centimeter horizontal. Chamberlain recommended finding the deepest vertical pocket by detecting the greatest amniotic fluid pocket after a global evaluation and selecting the largest vertical measurement with a minimum horizontal measurement of one centimetre. Calculate a two-diameter pocket by doubling the depth and breadth of the largest single pocket.

Understanding Fetal Growth Restriction (FGR) and Potential Causes

Globally, fetal growth restriction (FGR) causes stillbirths, neonatal deaths, and morbidity. Pathologic causes, primarily placental malfunctions, lead to fetuses failing to reach their genetic development potential. The classification of fetuses and babies who do not meet population-based weight standards is uneven. Previously, we characterized FGR as estimated fetal weight (EFW) or belly circumference below the tenth percentile for gestational age reference standards. Some fundamentally tiny foetuses are not growth-restricted, whereas others relevant to gestational-age foetuses who have not reached their maximum development potential are.

Managing Fetal Growth Concerns and Low Amniotic Fluid

Factors such as growth limitation, estimated gestational age, and other clinical markers, including prenatal foetal monitoring data, determine the risk of foetal death and the optimal timing for delivery. Premature fetuses under 28 weeks' gestation are at higher risk for problems such as bronchopulmonary dysplasia, intraventricular haemorrhage, and surgically necrotizing enterocolitis. Prematurity chances drop from 35% at 30 weeks to <10% at 34 weeks. Pregnancies under 30 weeks are associated with a 3-fold increase in neurodevelopmental delay and an 8-fold increase in cerebral palsy. Therefore, if perinatal mortality surpasses preterm issues, physicians must decide whether to deliver.

Signs and Symptoms of Abnormal Amniotic Fluid Levels

How to Recognise Issues with Amniotic Fluid Levels

Women seldom have symptoms from amniotic fluid imbalance. The mother may notice the fetus moving less than before. Before their due date, women with high amniotic fluid may have trouble breathing or uncomfortable contractions. Symptoms may result from amniotic fluid disorders.

Symptoms Expecting Mothers Should Be Aware Of

Amniotic sacs resemble water balloons. A tiny hole in the sac may form if the water balloon breaks, creating a powerful burst of fluid. This can slow amniotic fluid leakage. Pregnancy might make your bladder fill quicker and leak pee. Your vaginal tissues may create additional fluid to assist your baby's exit. Urine, amniotic, and vaginal fluids might be difficult to distinguish.

Treatment Options for Abnormal Amniotic Fluid Levels

Medical and Lifestyle Approaches to Managing Polyhydramnios and Oligohydramnios

Treatment for mild or end-of-pregnancy polyhydramnios is rare. Providers may schedule extra appointments to check your condition. Most pregnancies should be properly monitored. You may need treatment for severe polyhydramnios. That may involve addressing polyhydramnios' underlying illness, such as diabetes.

Alternative treatments: draining amniotic fluid.

Before your due date (generally 37–39 weeks), induce labor.

Procedures to Increase or Decrease Amniotic Fluid as Needed

Increasing water intake

Increased water intake raises amniotic fluid levels most. If amniotic fluid is low, your doctor will advise drinking more. Increased water intake during pregnancy helps maintain amniotic fluid levels.

Fewer activities limit amniotic fluid leakage.

Angioinvasion introduces saline from the cervix into the amniotic sac. Improves amniotic fluid. Although it is not a permanent solution, it can enhance the visibility of ultrasonography and improve the environment within the uterus.

Medicine can manage low amniotic fluid and dehydration.

Post-dehydration IV fluids promptly replenish amniotic fluids. If morning sickness prevents eating and drinking, IV fluids can increase amniotic fluid.

Drugs replenish uterine fluid.

Discussing pre-existing conditions Diabetes and hypertension diminish amniotic fluid. Physicians will monitor pregnant women who have low amniotic fluid without therapy.

Rest

Avoiding tiredness, they will monitor hydration. This ensures early delivery despite low amniotic fluid levels.

Get more fluids by eating more water. Increase amniotic fluid with hydration.

If the doctor cannot witness the baby die due to low amniotic fluid during delivery or during a scan, they will inject fluid. A fleeting glimpse of the newborn helps them decide.

Low amniotic fluid benefits.

From 36–37 week delivery. The baby is mature and ready. We induce labor to prevent low amniotic fluid levels.

The importance of foetal monitoring and ultrasounds is paramount.

How Fetal Monitoring Detects Amniotic Fluid Issues Early

We conduct prenatal screening for birth abnormalities and other diseases.
You can monitor the heart rate and vital signs of your infant remotely.
Radiologists and maternal-foetal medicine experts.
Understand your options with genetic counselors.
We offer medical-grade 3D and 4D ultrasonography that includes motion.
Watching ultrasounds
Use ultrasound to track your pregnancy. We screen your baby during your pregnancy to detect issues early. You and your baby are safe.

Frequency and Types of Fetal Ultrasounds in Pregnancy

The safest radiological modality for pregnant women is 2D ultrasounds, but use them sparingly. Two ultrasounds are typical for healthy pregConclusionnant women.

It is preferable to establish the due date in the first trimester and confirm normal anatomy and baby sex at 18–22 weeks. Most ladies don't require anything more than normal ultrasounds and gestational abdomen measurements.

Conclusion

Amniotic fluid is one of the important factors for pregnancy. However, if someone is experiencing any problems or abnormalities, they should visit the Ovum Hospital for treatment. The Ovum Hospital offers a wide range of treatment amenities and is renowned for its expertise.

FAQs

1: How does the daily production of amniotic fluid occur?

Maternal plasma first produces amniotic fluid, but in the second part of pregnancy, fetal urine and food increase it. Amniotic fluid reaches 800 ml at 28 weeks, plateaus until near term, and then decreases.

2: From whom comes amniotic fluid?

The sac contains amniotic fluid. Osmotic and hydrostatic forces carry it through embryonic membranes from maternal plasma. The fluid includes fetal urine, and the kidneys begin to function around week 16.

3: What is typical amniotic fluid?

Standard evaluation technique amniotic fluid index is 5–25 cm. Oligohydramnios is under 5 cm, and Polyhydram is over 25 cm

4: What colour is the amniotic fluid?

Colorless, yellow amniotic fluids are normal. Sometimes fluid is green or brown. This happens when the kid has its first bowel movement in the womb, called meconium. Most babies have their first bowel movement after birth

5: What occurs with low amniotic fluid?

Pregnancy with low amniotic fluid implies your baby has too little fluid surrounding it. Low levels of this fluid might influence foetal growth. It might affect labour and deliveries. Amniotic fluid protects your baby from bumps and pain.